Journal of Gvrontoloi; v 1977. Vol. 32. No. I.' 25-32
Activity Patterns of Elderly Men and Women1 Kenneth H. Sidney2 and Roy J. Shephard3
HE description of habitual activity has at T least two purposes in the context ofcardiorespiratory training—it serves to relate the cur-
being 3000 and 2200 kCal/day for men, and 2400 and 1760 kCal/day for women (World health Organization, 1973). Energy expenditures rent fitness of an individual to his genetic po- during working hours change relatively little in tential, and it brings to light discrepancies the elderly (Asmussen & Poulsen, 1963; Cunbetween perceived and actual activity that may ningham, Montoye, Metzner, & Keller, 1969) be keeping a person from taking an adequate but studies from both sides of the Atlantic have amount of exercise. In a study of mainly youn- shown a decrease of active leisure. In the city ger age groups, the men had a fair perception of Tecumseh, Michigan, most occupational of their daily activity, but the women showed groups spent 15 min. less per day on vigorous a smaller gradient of aerobic power with self- leisure pursuits as they became older (Cunningratings of voluntary exercise (Bailey, Shep- ham et al., 1969). Durnin (1964; 1969) also hard, Mirwald & McBride, 1974). The typical noted a 165 kCal/day diminution in the energy young Canadian city-dweller is extremely in- usage of older housewives relative to their adult active, heart rates of more than 120/min. being daughters; neither group engaged in strenuous a rarity (Shephard, 1967). However, cross- recreation, and the difference arose mainly sectional studies suggest that the addition of from a 45-min. reduction in daily walking with four or five 30-min. sessions of vigorous exer- aging. Nevertheless, most authors have found cise per week may be sufficient to boost aerobic considerable individual variation within a given power by 33% in the men and 20% in the age category. A person who was active in his women (Bailey et al., 1974). youth tends to remain active (Zborowski, Daily energy requirements have been as- 1962), and such a subject can have a higher sumed to decline with aging. Thus, nutritional daily caloric expenditure than a relatively inallowances for international reference subjects active miner or forestry worker even after redecrease from 20 to 60 years, respective figures tirement (Durnin & Passmore, 1967). The present report describes the habitual activity patterns of a group of elderly men and women enrolled in a preretirement exercise 'Dept. Preventive Medicine and Biostatistics Faculty of Medicine, University of Toronto. This work was presented by one of us (K.S.) in part fulprogram. Perceived and objective measurefillment of the requirements for a PhD degree, Univ. of Toronto. The support of the Dept. of National Health & Welfare (grant 605-7-734) is ments of physical activity are related, and acknowledged with thanks. Present address: Dept. of Physical Education, Laurentian Univ., Sudbury, changes induced by twelve months of endurOntario. ance training are described. 'Correspondence: 150 College St., Toronto M5S, IAI, Ontario, Canada. 2
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The activity patterns of elderly men and women ( > 60 years) were examined by diaries, ECG taperecorders, and electro-chemical integrators. Although the subjects thought that they were active relative to others of their age, both activity measurements and initial assessments of fitness indicated an inactive life style. At different periods of the day, the heart rate averaged 70-90 beats per minute, and the physical training threshold was rarely approached. During the week, the women engaged in 90 min. more physical activity than the men. However, at the weekend the men added an average of 100 min. of physical activity, whereas the women carried out 30 min. less physical work. Introduction of a 1-hour physical activity class four times per week increased the average daily energy expenditure by 150-200 kCal, to 2500 kCal in the men and 2200 kCal in the women. The added activity was sufficient to augment aerobic power, to induce favorable changes in body composition and to initiate change in other areas of life style, including a diminished use of the car.
26
SIDNEY AND S HEP HARD
METHODS
other operating procedures were carried out as described by Wolff. The apparatus was worn concurrently with the keeping of the 24-hour diaries, at the end of the 12-mo. training period. Subjects reported to the laboratory at 8 a.m. for the fitting of the electrodes and were instructed to follow a normal daily routine. Six E-cells were given to each subject, with instructions as to when they should be interchanged. Tape-recordings of the ECG. — A proportion of the subjects also wore a small portable amplifier and tape-recorder (Avionics Research Corp.; Holter, 1961) simultaneously with the SAMI device. The tape-recorder allowed direct registration of the electrocardiogram. Tapes ran for about 10 hours. The recorder was started concurrently with the noon exercise period and continued through to 10 p.m. An accelerated playback device (Electrocardioscanner, Avionics Corp.) was coupled to a digital counter and printing mechanism (Hewlett Packard), yielding heart rates for alternate minutes of the 10-hour observation period. The tape speed was calibrated between runs, and individual tapes were checked to ensure that an appropriate number of "minutes" had been recorded. RESULTS
Previous activity patterns. — Thirteen of the 21 women and 8 of the 13 men volunteering for the program thought that they had been more active than an average person in'their younger life, although only one member of the group had held a job with potential physical demands (5 years as a soldier). While at school, the majority (19/21 F; 10/13M) had played one or more sports, although usually not at a competitive level. Many of the group (14/21F; 11/13M) had also played some sports since leaving school. However, the areas where activity was thought to have been above average were walking (11/21F; 10/13M) and general leisure activities (13/21F; 9/13M) rather than domestic chores, hobbies, and sports. Currently perceived activity. — On entry to the program, 13 of the 21 women and all 13 of the men were employed by the University. Their occupations were relatively sedentary (teachers, librarians, administrators, technicians, and secretaries). The majority of the group also reported sedentary recreational activities. An inclusive list of current active
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Subjects. — The subjects were 13 men and 21 women who volunteered for endurance training as part of their preparation for retirement. Some were members of the University community and others were attracted by newspaper publicity describing the program. All of the group had passed an initial medical examination and an exercise stress test. The average age of the men was 65.2 ± 4.0 years, while that of the women was 64.8 ± 4.3 years. Patterns of physical activity were assessed from both retrospective and prospective diaries, and objective measurements of heart rate were made by the SAMI monitor and a portable taperecorder. Activity diaries were repeated in 11 persons who completed 1 year of physical training. Activity history. — The self-administered questionnaire suggested by the International Biological Program (Weiner & Lourie, 1969) was adapted (Sidney, 1975) to assess previous participation in physical activity, at school, at work, and during leisure hours. Particular attention was directed to involvement in physical activity immediately prior to joining the program. Prospective diaries. — On entry to the study, subjects completed a 7-day prospective activity diary. This was printed on a pocket-sized card, and each day subjects were asked to mark the number of minutes spent performing each of various listed activities. On completion of their training, a 24-hour prospective diary was kept; this indicated through an activity code the way in which each two minute period of a selected week-day had been occupied (Sidney, 1975; Weiner & Lourie, 1969). Electro-chemical integrator. — The SAMI monitor (Baker, Humphrey, & Wolff, 1967; Wolff, 1966) is a device that totals heart beats over a predetermined interval of several hours. Two adhesive chest electrodes feed the ECG signal to a small amplifier carried in the subject's pocket. Each ECG complex generates a constant charge pulse that deposits a fixed quantity of silver onto a gold electrode. At the end of the chosen period, the sealed electroplating unit (E cell) is transferred to a replay machine; this applies an opposite charge to the cell until its initial condition is restored. At the same time, a digital read-out of the accumulated heart beats is generated. Preparation of the electrode site (skin impedance ~ 10 kOhms), calibration of the instrument, and
27
AGE AND ACTIVITY
Table 1. Relationship Between Perceived Level of Current Activity and Aerobic Power as Predicted by Astrand Nomogram. Mean± S.D. and (N). Perceived Level of Current Physical Activity
Less active than average Average More active than average
VO2 (max) Predicted (ml. kg"1 min" 1 STPD Men
Women
20.7 + 4.9 (5) 24.5 ± 6.2 (8)
27.2± 4.9 (3) 23.5 ± 4 . 5 (8) 21.8+ 4.9 (10)
Ten of the 21 women and 8 of the 13 men also thought that they were currently more active than others of their age. However, there was no obvious relationship between this judgment and the current endurance fitness, as assessed from predictions (Sidney, 1975) of aerobic power (Table 1). Prospective diaries. — A number of the subjects kept the 7-day diaries poorly, overestimating the time engaged in various activities to the point that the daily tally substantially exceeded 1440 min. In a few instances, there were also indications that data had been transcribed from one day's log to the next. Analysis (Table 2) is thus restricted to 20 subjects who seem to have completed their diary sheets conscientiously. During the working week, the women reported spending a greater total time than the men on activities that they regarded as requiring physical effort; specifically, they allocated more time to walking and light physical effort, and less to sitting, driving, and sleeping. Nevertheless, neither sex spent long at what they regarded as "heavy" physical effort. Over the weekend, the men increased the proportion of their day allocated to light effort at the expense of sitting; there was also a suggestion that more time was being allocated to sleeping, eating, and activities requiring moderate effort. The women increased the time spent sleeping and eating, apparently at the
Table 2. Seven-Day Diary Records on Entry to Program. Mean± S.E. (Total Minutes per Activity) for 9 Men and 11 Women. Women
Men Activity Sitting
Mon.toFri. 436 ± 29
Sat./Sun.
Mon. to Fri.
Sat./Sun.
284 ± 39*
369 ± 40
339±4I
Standing
96± 14
80± 21
160± 37
145± 37
Walking
I I 8 ± 19
91 ± 18
135± 20
Driving
62 ± 12
65± 12
151 ± 24 7 ± 7"
Riding (car/bus/subway)
43± 15
40 ± 40
36± 14
68 ± 15
Dressing/bathing Eating
6
56 ± 53
99± 14
I13± 17
58± 7 89 ± 13
108+ 16^
467+ 18
5 I 3 ± 23
439± I I
474+ 17*
Sleeping
5I±
3 ± 2" 55± 4
Light physical effort
21± 10
109± 86 /;
63 ± 18
72+ 21
Moderate physical effort Heavy physical effort
4 I ± 10
109± 86 /; 10± 7
63 ± 18 ll± 8
72± 21 7± 4
Total Total min. active (walking & light to heavy effort)
7± 4 1440 187 ± 24
1440 288 ± 56
1440 282 ± 32
1440 248 ± 28
"Significant difference from men. "Significant difference from weekday. In 22 of the 140 days analyzed, the total number of minutes per day showed small discrepancies from 1440 (maximum 8%). All activities for these days have been scaled proportionally. A comparison of untreated and scaled data yields essentially similar conclusions.
c
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pursuits included gardening (4F; 3M), contemporary dance (IF), square-dancing (1M), golf (2M), figure skating and cycling (1M), and gliding (1M). With the possible exception of the square-dancer, detailed questioning did not suggest that these activities were pursued with unusual vigor or frequency. The majority of the group (13/21F; 7/13M) considered that they were currently less active than as a younger adult. The reason usually cited was a lack of opportunity, this judgment encompassing not only a lack of time but also an absence of facilities and program geared to their age group. Two women and 1 man commented that aging had reduced "energy" and increased their liability to fatigue, and 1 woman specifically blamed her reduction of activity upon aging. Nevertheless, 6 women and 2 men thought that they were more active than when they were younger, attributing this to a greater availability of time.
SIDNEY AND S HEPHARD
28
Table 3. Distribution of Activity Between Employment and Leisure Hours (Data for 7 Days, 9 Employed Men, 6 Employed Women, 5 Retired Women; Mean ± S.E.).
Activity
Employed* Men
Employed" Women
I37O± 182 3IO± 60 343± 82
1453 + 194 299± 112 222± 59
79 ± 34
183= 107
Retired Women
Occupational Sitting Standing Walking Moderate physical effort Heavy physical effort
Walking Driving Riding (car/bus/subway) Bathing/dressing Eating Sleeping Light physical effort Moderate physical effort Heavy physical effort Total minutes Total minutes active occupation" Total minutes active leisure"
13± 13
1376* 93
1551 ± 226 573 ±216 642 ± 167 79 ± 65 216± 58 386± 50 717± 160
332± 89 426+ 63 437± 71 295 ± 365 ± 720 ± 3361± 324± 284 ± 56 ±
135 40 100 122 81 91 35
1941 ± 247 1 3 4 4 * 401
1213 ±258 0 443* 416± 595 ± 3I87± 548 ± 264+ I29±
3108± 130 385 ± 143 244 ± 77 I3±
13
10,080
10.080 423 ± 97
418+ 136
1090* 135
1284 ± 128
168 69 97 136 229 96 98
10,080 2154 ± 346
"Sum of minutes spent walking and engaged in light to heavy effort. "Men worked an average of 5.2 days/week, employed women 5.0 days/week.
expense of a reduction in tasks requiring moderate effort. They also showed insignificant reductions in sitting, standing, and walking. Table 3 divided the 7-day diary results between occupational and leisure activities. Since some of the subjects worked on weekends, the periods spent on each activity has been totalled over the entire week. During working hours, the subjects spent less than 20% of their time in any form of activity (walking, or light to heavy effort); the most vigorous of the individual tasks reported was the stacking of books in the University library. During their leisure hours, the employed women devoted 61 min. per week more than the men to light physical effort, this presumably representing traditional female domestic chores. On the other hand, the men performed rather more heavy tasks. One interesting feature of the analysis was the increased proportion of the day that the recently retired women devoted to active tasks. Relative to those still employed, active pursuits occupied 65 more min. per day. The time spent travelling in vehicles also increased by some 20 min. per day. None of the retired women had taken up any formal sport or health-related activity, and these changes seem to have been "makework" projects aimed at occupying their day. Activity after training. — Eleven subjects who gave reliable 7-day diaries also filled out
Table 4. Reported Habitual Activity after 12 Months' Participation in Endurance Training Program (M= 5, F= 6). Summary of 24-Hour Daily Records Compared with Initial Data for 7-Day Period, Expressed as Min. per Day. Initial
Final
A ± S.D.
Sleeping
Activity
450
438
12+ 20
Sitting'' Standing
496 144
496
0+ 53
153
-9 ±48 32± 13"
36
4
135
129
Dressing/bathing
56
48
8±
Light physical effort
88
-42 ±43
Moderate physical effort
46 42
70
- 2 8 ± 37
Heavy physical effort
13
0
13± 8
235
301
- 6 6 ± 48
Driving Walking^
Total min. active (sum of walking plus light to heavy effort)
6+33 9
"Significant difference between initial and final assessment. * Includes also running and stair climbing. c Includes also eating and riding as a passenger.
the 24-hour diary sheets after completing 12 mo. of endurance training. Comparison of the two sets of data (Table 4) suggests that after training less time was spent driving cars (particularly by the men) and performing ablutions (particularly by the women), with corresponding increments in the time allocated to active pursuits.
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Leisure Sitting Standing
0
29
AGE AND ACTIVITY
for the exercise class were more satisfactory, the average figures coinciding well with palpated readings (average of 56 manual counts on 18 men and women, 110 ± 16 beats/min). The frequency distribution of the taperecorded heart rate data shows that even during the exercise hour, a substantial part of the allocated time was spent at heart rates lower than 120/min. (Table 6). During work and leisure hours, readings of more than 120/min. were few, and related to emotional disturbances or isometric effort as often as to aerobic stress. Nevertheless, there were suggestive, but statistically insignificant correlations between the sleeping heart rate and aerobic power (ml./kg. min), amounting to —0.53 in the men and -0.14 in the women. DISCUSSION
Activity patterns of volunteers. — The subjects examined were all volunteers for an endurance training program and thus may have had an above average interest infitnessand health.4 They were drawn mainly from white-collar categories, who are traditionally more inclined than manual workers to take deliberate leisure "Elderly volunteers for clinical examination seem less healthy than the general population of the same age (Milne, Maule, & Williamson, 1971); however, we suspect that the exercise emphasis of our program tended to attract those with above average health.
Table 5. Intensity of Habitual Activity (Mean Heart Rates, Beats/Min., for Specified Periods. Data Obtained Using a SAMI Electro-Chemical Pulse Integrator (M = 8, F= 10) and Tape-Recordings of ECG (M= 6, F= 8). Mean ± S.E. Tape ECG Values
SAMI Values Men
Women
78.4 ± 6.4 92.0 ± 7.8
II5.O± 2.7
107.0+ 5.1
4.4
81.4= 4.4
90.5 ± 5.6
Evening leisure
80.9 ± 4.1
82.6± 3.2
87.6± 3.1
79.9 ± 4.4 81.0± 3.4
Sleep
62.6 ±
8.5
64.0± 1.0 90.9 ± 4.0
84.4+ 3.1
Men
Women
89.1 ± 6.8 72.3 ± 5.2 84.0 ± 11.3
88.8 ± 4.9
80.5 ±
Period of Day Before work Morning work Exercise " h o u r " " Afternoon work
10-hr, average
8I.4±
3.1
85.6± 2.9
Daytime average
80.8 ±
3.5
83.5 ± 2 . 7
24-hr, average
76. l ±
2.2
78.6 ± 2.1
"Satisfactory data obtained on only 5 men and 4 women using SAMI & 5 men, 5 women using tape-recorder.
Table 6. Frequency Distribution of Heart-Rate for Specified Periods of the Day. Data Obtained from Tape-Recordings of the ECG (Minutes in Specified Frequency Range, Mean± S.E.).
Period of day
120 Beats/Min
M
F
M
F
3
28 ± 5
17± 6
30±5
8± 5
Afternoon workt
175 ± 21
222± 10
35 ± 10
29 ± 9
15±6
ll±6
Evening leisure!
2I2± 31
262 ± 18
42± 16
27 ± 10
10±2
9±5
Exercise "hour"*
•M=5, F=5 tM= 6. F= 8
I9±
7
9±
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Somewhat surprisingly, there was a negative correlation between the reported minutes active per day and the directly measured aerobic power (r = -0.68 for the men (N= 11), -0.63 for the women (N = 10): Heart rate measurements. — Average SAMI heart rate readings (Table 5) were remarkably low for all segments of the day, including the "exercise hour." Among the female subjects, there was a fair concordance of SAMI and taperecorded data for afternoon work and evening leisure. However, the SAMI cells necessarily included in their average time spent in travelling to and from the sports field, changing, and sitting awaiting the commencement of formal instruction. In the male subjects, the SAMI apparatus yielded consistently lower heart rates than the tape-recorded values. The discrepancy is rather large to attribute to a few differences in the subjects tested by the two methods and probably reflects undetected faults of electrode contact during use of the SAMI equipment; obvious contact problems led to rejection of electro-chemical integrations for three of the 12 subjects during the exercise session. However, if the apparent heart rate falls within a plausible range, there is no basis for rejecting data (Edholm, Humphrey, Lourie, Tredre, & Brotherhood, 1973). The tape-recorded rates
30
SIDNEY AND SHEPHARD their fitness prior to entry into the exercise program, what is the situation of other groups such as senior citizens clubs, homes for the aged, and geriatric wards? Comparisons may be made in terms of total caloric expenditures, reported activities, and heart rate measurements. The over-all caloric expenditures of our volunteers can be calculated from Tables 2 and 3, using standard values for the energy cost of the various tasks listed (Durnin & Passmore, 1967; Sidney, 1975). The data show that relative to other elderly groups, the augmentation of daily energy expenditure (150-200 kCal/day) at least equalled the net cost of the exercise "hour." In the men, the average daily total (2500 kCal) was comparable with the young office-worker (2520 kCal, Durnin & Passmore, 1967), not much less than the figure for older men in light industry (2684 kCal, Durnin, Blake, Allan, Shaw, Wilson, Blair, & Yuill, 1961), and substantially greater than that commonly encountered in retired (2330 kCal, Durnin & Passmore, 1967)and institutionalized men (2116 kCal, Salvosa, Payne, & Wheeler, 1971). Among the women, our daily totals were similar for the employed (2264 kCal) and those recently retired (2212 kCal). Figures were comparable with those for young University students in Scotland (2290 kCal, Durnin & Passmore, 1967) and young salesgirls (2255 kCal, Durnin, Blake, & Brockway, 1960), but substantially greater than data for elderly housewives with families (2113 kCal, Durnin, 1966), elderly housewives living alone (1987 kCal, Durnin, 1966), retired women living at home (1700 kCal, Salvosa et al., 1971), and institutionalized women (1566 kCal, Salvosa et al., 1971). We may thus conclude that if our subjects were initially taking insufficient physical activity to sustain fitness, this is even more true of other segments of the elderly population. The results also suggest that an exercise hour sufficient to induce cardio-respiratory training can be added to the day without bringing about compensatory decreases in other forms of vigorous activity; indeed, over the year of observation, our subjects apparently initiated some beneficial changes in activity patterns at other times during the day, including a decreased use of their cars. Few previous studies give detailed descriptions of daily activities in the elderly. Relative to young men (Edholm, 1967; Shephard, 1967), our old subjects spent more time on walking
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activity (Durnin, 1967; Cunningham et al., 1969). The individuals concerned also thought that they were more active than the general population of their age. Nevertheless, the data for cardio-respiratory fitness (Sidney, 1975) suggest that on entry to the program activity levels were far from sufficient to realize their genetic potential. At the initial appraisal, maximum oxygen intake (23.5 ml/kg/min in the men, 23.4 ml/kg/min in the women), excess weight (9.3 kg in the men, 8.1 kg in the women) and average skinfold thickness (16.2 mm in the men, 21.1 mm in the women) were no better than in other Canadian city-dwellers of the same age (Bailey et al., 1974; Shephard, 1969). Further, 3 mo. of endurance training sufficed to increase aerobic power by as much as 30%. The paradox of perceived activity but low fitness levels can be explained in several ways. It may be that a person who is unfit takes longer to perform a physical task and finds it fatiguing, thus convincing himself that he is working hard; in support of this view, we found the rating of perceived exertion (Borg, 1971) to be 3 to 4 units higher at any given heart rate than would be the case in young (Sidney, 1975; Skinner, Hutsler, Berg^ y , g steinova & Buskirk, 1973). Societal expectations also diminish with aging; a recent survey from the USA showed that while few old people were taking any deliberate exercise, 71% of those over the age of 60 considered that they took sufficient activity (Clarke, 1974). The base-line for comparison is extreme inactivity. Statistics Canada (1972) reported that people over the age of 65 years led the rest of the nation in watching more than 4 hours of television per day, with less than 9% of those over the age of 55 taking any deliberate exercise. Any activity that is undertaken is typically gentle walking rather than vigorous sport, and the vigor is rarely sufficient to reach the threshold where a training effect could be anticipated (Cunningham et al., 1969). Even in the elderly, cardio-respiratory training is unlikely unless a heart rate of 120/min is surpassed for several minutes (Shephard, 1968). It is thus not surprising that there was no relationship between the initial perceived activity of our exercise volunteers and objective measurements of their endurance fitness. Activity patterns of other elderly populations. — Given that our sample of volunteers were not taking enough activity to maintain
AGE AND ACTIVITY
Table 7. Previously Reported Average Heart Rates.
Subjects Middle-aged men Policemen Men aged 16-70 (no age differences) Men Type A Men Type B
Work
Active Leisure
Sleep
84
85
67
86-94 71-106
83-85 71-106
64-68 48-80
86 85
83 79
71 66
Note: Authors: Richardson (1971); Goldsmith & Hale (1971); Glagov et al. (1970); Friedman et al. (1963).
to 1.38 per 100. Those following good health practices including regular physical activity had a health status (measured in terms of hospital admissions and medical consultations) equivalent to the general population who were 30 years younger (Belloc & Breslow, 1972). A similar study by Palmore (1970) showed that more than four times as many inactive subjects reported poor health as those who were engaged in regular physical activities. While all of these studies are suggestive of a health benefit from an increase of physical activity, they do not exclude the possibility that poor health may have influenced the initial decision not to take physical activity in at least a proportion of those who were inactive. The longitudinal experience with our sample of elderly subjects showed significant gains in perceived health in response to training (Sidney & Shephard, 1976a). However, a categorical answer to the question of health benefits must await a much larger longitudinal study in which fitness and activity levels are correlated with objective measures of health experience. SUMMARY
Questionnaires on past and current participation in physical activity were given to 13 men and 21 women aged 60 years and over who had volunteered for a program of endurance training. Additional information was collected by 7-day and 24-hour prospective diaries, along with measurements of heart rate made by SAMI electrochemical integrator and taperecorder. Volunteers were either retired or engaged in sedentary occupations and their leisure pursuits also were initially inactive, data from the diary records and heart rate counts being confirmed by objective measures of physical fitness. Nevertheless, the subjects thought that they were more active than others of their age. Explanations of this paradox are discussed. Outside of the exercise hour, activity patterns were much as reported in previous surveys of elderly working subjects. During the week, the women engaged in 90 min. more activity than the men, but at the weekend the men added an average of 100 min. of physical activity, while the women engaged in 30 min. less physical activity than on weekdays. At different periods of the day, the heart rate averaged 70 to 90 beats/min., and heart rates where cardio-respiratory training might be anticipated were rarely encountered. The exercise hour apparently augmented the daily caloric expen-
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and less on sitting. The women spend substantially less time lying than previous samples of Scottish ladies (509, 510, and 581 min., Durnin etal., 1960, 1961; Durnin, Blake, Brockway, & Drury, 1961). Our employed ladies also spent less time on housework than the Scottish sample, but this reflects their career rather than the . availability of domestic appliances, since figures for our retired women were comparable with those seen by Durnin and his associates. In contrast to our data, Durnin's elderly women spent relatively little time walking (66, 66, and 45 min.), and he comments (Durnin, 1964; 1969) that the main effect of aging was a 45-min. diminution in walking per day. Our experience with the two methods of heart-rate counting confirms the general conclusion of International Biological Programme Investigators (Shephard, 1976) that the taperecorder is more satisfactory than the SAMI equipment. Nevertheless, SAMI figures for periods other than the exercise hour seem generally comparable with those reported in the literature (Table 7). If the training threshold at this age is a heart rate of 120/min., our subjects were getting a maximum stimulation of 30-40 min. per day, excluding their exercise hour; much of this time could of course be discounted, since the tachycardia was commonly caused by emotion or isometric effort rather than by aerobic stress. In agreement with Glagov, Rowley, Gramer, & Page (1970), 80% of waking values were less than 10 beats per minute higher than those encountered during sleep! Health significance of activity. — How important is it to health that the elderly become more active, realizing their fitness potential? Hammond (1964) found death rates to show a gradation with activity; in men aged 60-64 years, the range was from 4.9 per 100 in those taking no exercise to 0.92 in those taking regular heavy exercise, while in those aged 65-69 years the gradient was even steeper, from 10.33
31
32
SIDNEY AND S HEP HARD
diture by 150-200 kCal, totals (2500 kCal for the men, 2200 kCal for the women) being substantially larger than in previous studies of elderly desk workers. The added exercise was sufficient to improve both aerobic power and body composition over the year of observation. Further, the program of endurance activity apparently had some carry-over into other areas of life style, notably a diminished use of the car by the men.
134, 1214-1200.
Milne, J. S., Maule, M. M., & Williamson, J. Method of sampling in a study of older people with a comparison of respondents and non-respondents. British Journal of Preventive or Social Medicine, 1971, 25, 37-41. Palmore, E. Health practices and illnesses among the aged. Gerontologist, 1970,70, 313-316. Salvosa, C. B., Payne, P. R., & Wheeler, E. F. Energy expenditure of elderly people living alone or in local authority homes. American Journal of Clinical Nutrition, 1971,24, 1467-1470. Shephard, R. J. Normal levels of activity in Canadian city dwellers. Canadian Medical Association Journal, 1967, 97, 313-318. Shephard, R. J. Working capacity of selected populations. In J. Weiner (Ed.), /. B. P. Synthesis, Vol. 4, Human Adaptability Project. University Press, Cambridge, 1976. Shephard, R. J. Intensity, duration and frequency of exercise as determinants of the response to a training regimen. Internationale Zeitschrift fur angewandte physiologie, 1968, 26, 272-278. Shephard, R. J. Endurance fitness. University Press, Toronto, 1969. Sidney, K. H. Responses of elderly subjects to a program of progressive exercise training. PhD Thesis, Univ. Toronto, 1975. Sidney, K. H., & Shephard, R. J. Attitudes towards health and physical training programme. Medicine & Science in Sports, 1976. (in press) Skinner, J. S., Hutsler, R., Bergsteinova, V., & Buskirk, E. R. Perception of effort under different types of exercise and under different environmental conditions. Medicine & Science in Sports, 1973,5, 110-115. Statistics Canada. Survey of physical activity, 1971. Preliminary findings reported in Medical Post, July, 1972. Weiner, J., & Lourie, J. A. Human biology. A guide to field methods. Blackwell, Oxford, 1969. Wolff, H. S. Physiological measurements on human subjects in the field, with special reference to a new approach to data storage. In H. Yoshimura & J. S. Weiner (Eds.), Human adaptability and its methodology. Society for the Promotion of Sciences, Tokyo, 1966. World Health Organization. Energy and Protein Requirements. Report of a joint FAO/WHO ad hoc expert committee. Technical Report. 522, (Geneva), 1973. Zborowski, M. Aging and recreation. Journal of Gerontology, 1962, 17, 302-309.
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REFERENCES
Asmussen, E., & Poulsen, E. Energy expenditure in light industry. Its relation to age, sex and aerobic capacity. Communications from Danish National Association for Infantile Paralysis, 1963, 13: 3-13. Bailey, D. A., Shephard, R. J., Mirwald, R. L., & McBride, G. A. A current view of cardiorespiratory fitness levels of Canadians. Canadian Medical Association Journal, 1974, 777, 25-30. Baker, J. A., Humphrey, S. J. E., & Wolff, H. S. Socially monitoring instruments (SAMI. Journal of Physiology (Lond.), 1967, 188, 4p. Belloc, N. B., & Breslow, L. Relationship of physical status and health practices. Preventive Medicine, 1972, /, 409-421. Borg, G. Perception of physical performance. In. R. J. Shephard (Ed), Frontiers of fitness. Charles C Thomas, Springfield, IL, 1971. Clarke, H. H. Circulatory-respiratory endurance improvement. Physical Fitness Research Digest, 1974, 4, 1-16. Cunningham, D. A., Montoye, H. J., Metzner, H. L., & Keller, J. B. Physical activity at work and active leisure as related to occupation. Medicine & Science in Sports, 1969, /, 165-170. Durnin, J. V. G. A. The dietary intake of the elderly. In W. F. Anderson & B. Isaacs (Eds.), Current achievements in geriatrics. Cassel, London, 1964. Durnin, J. V. G. A. Age, physical activity and energy expenditure. Proceedings of Nutrition Society, 1966, 25, 107-113. Durnin, J. V. G. A. Activity patterns in the community. In: Proceedings of International Symposium on Physical Activity and Health. Canadian Medical Association Journal, 1967, 96, 882-886. Durnin, J. V. G. A. Energy expenditure in relation to age, sex, body weight, and physical activity. Excerpta Medica International Congress Series, 213, Proceedings of 8th International Congress on Nutrition, Prague, 1969. Durnin, J. V. G. A., Blake, E. C , & Brockway, J. M. The energy expenditure and food intake of middle-aged Glasgow housewives and their adult daughters. British Journal of Nutrition, 1960,77, 85-94. Durnin, J. V. G. A. Blake, E. C , Allan, M. K., Shaw, E. J., Wilson, E. A., Blair, S., & Yuill, S. A. The food intake and energy expenditure of some elderly men working in heavy and light engineering. British Journal of Nutrition, 1961,75, 587-591. Durnin, J. V. G. A., Blake, E. C , Brockway, J. M., & Drury, E. A. The food intake and energy expenditure of elderly women living alone. British Journal of Nutrition, 1961,75, 499-506.
Durnin, J. V. G. A. & Passmore, R. Energy, work and leisure. Heinemann, London, 1967. Edholm, O. G. The biology of work. McGraw Hill, New York, 1967. Edholm, O. G., Humphrey, S., Lourie, J. A., Tredre, B. E., & Brotherhood, J. Energy expenditure and climatic exposure of Yemenite and Kurdish Jews in Israel. Philosophical Transactions of the Royal Society of London, Biological Sciences, 1973, B 266, 127-140. Glagov, S., Rowley, D. A., Gramer, D. B., & Page, R. G. Heart rates during 24 hours of usual activity for 100 normal men. Journal of Applied Physiology, 1970, 29, 799-805. Hammond, E. C. Smoking in relation to mortality & morbidity. Findings in first thirty-four months of follow-up in a prospective study started in 1959. Journal of the National Cancer Institute, 1964, 32, 1161-1188. Holter, N. J. New method for heart studies. Science, 1961,
Activity Patterns of Elderly Men and Women1 Kenneth H. Sidney2 and Roy J. Shephard3
HE description of habitual activity has at T least two purposes in the context ofcardiorespiratory training—it serves to relate the cur-
being 3000 and 2200 kCal/day for men, and 2400 and 1760 kCal/day for women (World health Organization, 1973). Energy expenditures rent fitness of an individual to his genetic po- during working hours change relatively little in tential, and it brings to light discrepancies the elderly (Asmussen & Poulsen, 1963; Cunbetween perceived and actual activity that may ningham, Montoye, Metzner, & Keller, 1969) be keeping a person from taking an adequate but studies from both sides of the Atlantic have amount of exercise. In a study of mainly youn- shown a decrease of active leisure. In the city ger age groups, the men had a fair perception of Tecumseh, Michigan, most occupational of their daily activity, but the women showed groups spent 15 min. less per day on vigorous a smaller gradient of aerobic power with self- leisure pursuits as they became older (Cunningratings of voluntary exercise (Bailey, Shep- ham et al., 1969). Durnin (1964; 1969) also hard, Mirwald & McBride, 1974). The typical noted a 165 kCal/day diminution in the energy young Canadian city-dweller is extremely in- usage of older housewives relative to their adult active, heart rates of more than 120/min. being daughters; neither group engaged in strenuous a rarity (Shephard, 1967). However, cross- recreation, and the difference arose mainly sectional studies suggest that the addition of from a 45-min. reduction in daily walking with four or five 30-min. sessions of vigorous exer- aging. Nevertheless, most authors have found cise per week may be sufficient to boost aerobic considerable individual variation within a given power by 33% in the men and 20% in the age category. A person who was active in his women (Bailey et al., 1974). youth tends to remain active (Zborowski, Daily energy requirements have been as- 1962), and such a subject can have a higher sumed to decline with aging. Thus, nutritional daily caloric expenditure than a relatively inallowances for international reference subjects active miner or forestry worker even after redecrease from 20 to 60 years, respective figures tirement (Durnin & Passmore, 1967). The present report describes the habitual activity patterns of a group of elderly men and women enrolled in a preretirement exercise 'Dept. Preventive Medicine and Biostatistics Faculty of Medicine, University of Toronto. This work was presented by one of us (K.S.) in part fulprogram. Perceived and objective measurefillment of the requirements for a PhD degree, Univ. of Toronto. The support of the Dept. of National Health & Welfare (grant 605-7-734) is ments of physical activity are related, and acknowledged with thanks. Present address: Dept. of Physical Education, Laurentian Univ., Sudbury, changes induced by twelve months of endurOntario. ance training are described. 'Correspondence: 150 College St., Toronto M5S, IAI, Ontario, Canada. 2
25
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The activity patterns of elderly men and women ( > 60 years) were examined by diaries, ECG taperecorders, and electro-chemical integrators. Although the subjects thought that they were active relative to others of their age, both activity measurements and initial assessments of fitness indicated an inactive life style. At different periods of the day, the heart rate averaged 70-90 beats per minute, and the physical training threshold was rarely approached. During the week, the women engaged in 90 min. more physical activity than the men. However, at the weekend the men added an average of 100 min. of physical activity, whereas the women carried out 30 min. less physical work. Introduction of a 1-hour physical activity class four times per week increased the average daily energy expenditure by 150-200 kCal, to 2500 kCal in the men and 2200 kCal in the women. The added activity was sufficient to augment aerobic power, to induce favorable changes in body composition and to initiate change in other areas of life style, including a diminished use of the car.
26
SIDNEY AND S HEP HARD
METHODS
other operating procedures were carried out as described by Wolff. The apparatus was worn concurrently with the keeping of the 24-hour diaries, at the end of the 12-mo. training period. Subjects reported to the laboratory at 8 a.m. for the fitting of the electrodes and were instructed to follow a normal daily routine. Six E-cells were given to each subject, with instructions as to when they should be interchanged. Tape-recordings of the ECG. — A proportion of the subjects also wore a small portable amplifier and tape-recorder (Avionics Research Corp.; Holter, 1961) simultaneously with the SAMI device. The tape-recorder allowed direct registration of the electrocardiogram. Tapes ran for about 10 hours. The recorder was started concurrently with the noon exercise period and continued through to 10 p.m. An accelerated playback device (Electrocardioscanner, Avionics Corp.) was coupled to a digital counter and printing mechanism (Hewlett Packard), yielding heart rates for alternate minutes of the 10-hour observation period. The tape speed was calibrated between runs, and individual tapes were checked to ensure that an appropriate number of "minutes" had been recorded. RESULTS
Previous activity patterns. — Thirteen of the 21 women and 8 of the 13 men volunteering for the program thought that they had been more active than an average person in'their younger life, although only one member of the group had held a job with potential physical demands (5 years as a soldier). While at school, the majority (19/21 F; 10/13M) had played one or more sports, although usually not at a competitive level. Many of the group (14/21F; 11/13M) had also played some sports since leaving school. However, the areas where activity was thought to have been above average were walking (11/21F; 10/13M) and general leisure activities (13/21F; 9/13M) rather than domestic chores, hobbies, and sports. Currently perceived activity. — On entry to the program, 13 of the 21 women and all 13 of the men were employed by the University. Their occupations were relatively sedentary (teachers, librarians, administrators, technicians, and secretaries). The majority of the group also reported sedentary recreational activities. An inclusive list of current active
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Subjects. — The subjects were 13 men and 21 women who volunteered for endurance training as part of their preparation for retirement. Some were members of the University community and others were attracted by newspaper publicity describing the program. All of the group had passed an initial medical examination and an exercise stress test. The average age of the men was 65.2 ± 4.0 years, while that of the women was 64.8 ± 4.3 years. Patterns of physical activity were assessed from both retrospective and prospective diaries, and objective measurements of heart rate were made by the SAMI monitor and a portable taperecorder. Activity diaries were repeated in 11 persons who completed 1 year of physical training. Activity history. — The self-administered questionnaire suggested by the International Biological Program (Weiner & Lourie, 1969) was adapted (Sidney, 1975) to assess previous participation in physical activity, at school, at work, and during leisure hours. Particular attention was directed to involvement in physical activity immediately prior to joining the program. Prospective diaries. — On entry to the study, subjects completed a 7-day prospective activity diary. This was printed on a pocket-sized card, and each day subjects were asked to mark the number of minutes spent performing each of various listed activities. On completion of their training, a 24-hour prospective diary was kept; this indicated through an activity code the way in which each two minute period of a selected week-day had been occupied (Sidney, 1975; Weiner & Lourie, 1969). Electro-chemical integrator. — The SAMI monitor (Baker, Humphrey, & Wolff, 1967; Wolff, 1966) is a device that totals heart beats over a predetermined interval of several hours. Two adhesive chest electrodes feed the ECG signal to a small amplifier carried in the subject's pocket. Each ECG complex generates a constant charge pulse that deposits a fixed quantity of silver onto a gold electrode. At the end of the chosen period, the sealed electroplating unit (E cell) is transferred to a replay machine; this applies an opposite charge to the cell until its initial condition is restored. At the same time, a digital read-out of the accumulated heart beats is generated. Preparation of the electrode site (skin impedance ~ 10 kOhms), calibration of the instrument, and
27
AGE AND ACTIVITY
Table 1. Relationship Between Perceived Level of Current Activity and Aerobic Power as Predicted by Astrand Nomogram. Mean± S.D. and (N). Perceived Level of Current Physical Activity
Less active than average Average More active than average
VO2 (max) Predicted (ml. kg"1 min" 1 STPD Men
Women
20.7 + 4.9 (5) 24.5 ± 6.2 (8)
27.2± 4.9 (3) 23.5 ± 4 . 5 (8) 21.8+ 4.9 (10)
Ten of the 21 women and 8 of the 13 men also thought that they were currently more active than others of their age. However, there was no obvious relationship between this judgment and the current endurance fitness, as assessed from predictions (Sidney, 1975) of aerobic power (Table 1). Prospective diaries. — A number of the subjects kept the 7-day diaries poorly, overestimating the time engaged in various activities to the point that the daily tally substantially exceeded 1440 min. In a few instances, there were also indications that data had been transcribed from one day's log to the next. Analysis (Table 2) is thus restricted to 20 subjects who seem to have completed their diary sheets conscientiously. During the working week, the women reported spending a greater total time than the men on activities that they regarded as requiring physical effort; specifically, they allocated more time to walking and light physical effort, and less to sitting, driving, and sleeping. Nevertheless, neither sex spent long at what they regarded as "heavy" physical effort. Over the weekend, the men increased the proportion of their day allocated to light effort at the expense of sitting; there was also a suggestion that more time was being allocated to sleeping, eating, and activities requiring moderate effort. The women increased the time spent sleeping and eating, apparently at the
Table 2. Seven-Day Diary Records on Entry to Program. Mean± S.E. (Total Minutes per Activity) for 9 Men and 11 Women. Women
Men Activity Sitting
Mon.toFri. 436 ± 29
Sat./Sun.
Mon. to Fri.
Sat./Sun.
284 ± 39*
369 ± 40
339±4I
Standing
96± 14
80± 21
160± 37
145± 37
Walking
I I 8 ± 19
91 ± 18
135± 20
Driving
62 ± 12
65± 12
151 ± 24 7 ± 7"
Riding (car/bus/subway)
43± 15
40 ± 40
36± 14
68 ± 15
Dressing/bathing Eating
6
56 ± 53
99± 14
I13± 17
58± 7 89 ± 13
108+ 16^
467+ 18
5 I 3 ± 23
439± I I
474+ 17*
Sleeping
5I±
3 ± 2" 55± 4
Light physical effort
21± 10
109± 86 /;
63 ± 18
72+ 21
Moderate physical effort Heavy physical effort
4 I ± 10
109± 86 /; 10± 7
63 ± 18 ll± 8
72± 21 7± 4
Total Total min. active (walking & light to heavy effort)
7± 4 1440 187 ± 24
1440 288 ± 56
1440 282 ± 32
1440 248 ± 28
"Significant difference from men. "Significant difference from weekday. In 22 of the 140 days analyzed, the total number of minutes per day showed small discrepancies from 1440 (maximum 8%). All activities for these days have been scaled proportionally. A comparison of untreated and scaled data yields essentially similar conclusions.
c
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pursuits included gardening (4F; 3M), contemporary dance (IF), square-dancing (1M), golf (2M), figure skating and cycling (1M), and gliding (1M). With the possible exception of the square-dancer, detailed questioning did not suggest that these activities were pursued with unusual vigor or frequency. The majority of the group (13/21F; 7/13M) considered that they were currently less active than as a younger adult. The reason usually cited was a lack of opportunity, this judgment encompassing not only a lack of time but also an absence of facilities and program geared to their age group. Two women and 1 man commented that aging had reduced "energy" and increased their liability to fatigue, and 1 woman specifically blamed her reduction of activity upon aging. Nevertheless, 6 women and 2 men thought that they were more active than when they were younger, attributing this to a greater availability of time.
SIDNEY AND S HEPHARD
28
Table 3. Distribution of Activity Between Employment and Leisure Hours (Data for 7 Days, 9 Employed Men, 6 Employed Women, 5 Retired Women; Mean ± S.E.).
Activity
Employed* Men
Employed" Women
I37O± 182 3IO± 60 343± 82
1453 + 194 299± 112 222± 59
79 ± 34
183= 107
Retired Women
Occupational Sitting Standing Walking Moderate physical effort Heavy physical effort
Walking Driving Riding (car/bus/subway) Bathing/dressing Eating Sleeping Light physical effort Moderate physical effort Heavy physical effort Total minutes Total minutes active occupation" Total minutes active leisure"
13± 13
1376* 93
1551 ± 226 573 ±216 642 ± 167 79 ± 65 216± 58 386± 50 717± 160
332± 89 426+ 63 437± 71 295 ± 365 ± 720 ± 3361± 324± 284 ± 56 ±
135 40 100 122 81 91 35
1941 ± 247 1 3 4 4 * 401
1213 ±258 0 443* 416± 595 ± 3I87± 548 ± 264+ I29±
3108± 130 385 ± 143 244 ± 77 I3±
13
10,080
10.080 423 ± 97
418+ 136
1090* 135
1284 ± 128
168 69 97 136 229 96 98
10,080 2154 ± 346
"Sum of minutes spent walking and engaged in light to heavy effort. "Men worked an average of 5.2 days/week, employed women 5.0 days/week.
expense of a reduction in tasks requiring moderate effort. They also showed insignificant reductions in sitting, standing, and walking. Table 3 divided the 7-day diary results between occupational and leisure activities. Since some of the subjects worked on weekends, the periods spent on each activity has been totalled over the entire week. During working hours, the subjects spent less than 20% of their time in any form of activity (walking, or light to heavy effort); the most vigorous of the individual tasks reported was the stacking of books in the University library. During their leisure hours, the employed women devoted 61 min. per week more than the men to light physical effort, this presumably representing traditional female domestic chores. On the other hand, the men performed rather more heavy tasks. One interesting feature of the analysis was the increased proportion of the day that the recently retired women devoted to active tasks. Relative to those still employed, active pursuits occupied 65 more min. per day. The time spent travelling in vehicles also increased by some 20 min. per day. None of the retired women had taken up any formal sport or health-related activity, and these changes seem to have been "makework" projects aimed at occupying their day. Activity after training. — Eleven subjects who gave reliable 7-day diaries also filled out
Table 4. Reported Habitual Activity after 12 Months' Participation in Endurance Training Program (M= 5, F= 6). Summary of 24-Hour Daily Records Compared with Initial Data for 7-Day Period, Expressed as Min. per Day. Initial
Final
A ± S.D.
Sleeping
Activity
450
438
12+ 20
Sitting'' Standing
496 144
496
0+ 53
153
-9 ±48 32± 13"
36
4
135
129
Dressing/bathing
56
48
8±
Light physical effort
88
-42 ±43
Moderate physical effort
46 42
70
- 2 8 ± 37
Heavy physical effort
13
0
13± 8
235
301
- 6 6 ± 48
Driving Walking^
Total min. active (sum of walking plus light to heavy effort)
6+33 9
"Significant difference between initial and final assessment. * Includes also running and stair climbing. c Includes also eating and riding as a passenger.
the 24-hour diary sheets after completing 12 mo. of endurance training. Comparison of the two sets of data (Table 4) suggests that after training less time was spent driving cars (particularly by the men) and performing ablutions (particularly by the women), with corresponding increments in the time allocated to active pursuits.
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Leisure Sitting Standing
0
29
AGE AND ACTIVITY
for the exercise class were more satisfactory, the average figures coinciding well with palpated readings (average of 56 manual counts on 18 men and women, 110 ± 16 beats/min). The frequency distribution of the taperecorded heart rate data shows that even during the exercise hour, a substantial part of the allocated time was spent at heart rates lower than 120/min. (Table 6). During work and leisure hours, readings of more than 120/min. were few, and related to emotional disturbances or isometric effort as often as to aerobic stress. Nevertheless, there were suggestive, but statistically insignificant correlations between the sleeping heart rate and aerobic power (ml./kg. min), amounting to —0.53 in the men and -0.14 in the women. DISCUSSION
Activity patterns of volunteers. — The subjects examined were all volunteers for an endurance training program and thus may have had an above average interest infitnessand health.4 They were drawn mainly from white-collar categories, who are traditionally more inclined than manual workers to take deliberate leisure "Elderly volunteers for clinical examination seem less healthy than the general population of the same age (Milne, Maule, & Williamson, 1971); however, we suspect that the exercise emphasis of our program tended to attract those with above average health.
Table 5. Intensity of Habitual Activity (Mean Heart Rates, Beats/Min., for Specified Periods. Data Obtained Using a SAMI Electro-Chemical Pulse Integrator (M = 8, F= 10) and Tape-Recordings of ECG (M= 6, F= 8). Mean ± S.E. Tape ECG Values
SAMI Values Men
Women
78.4 ± 6.4 92.0 ± 7.8
II5.O± 2.7
107.0+ 5.1
4.4
81.4= 4.4
90.5 ± 5.6
Evening leisure
80.9 ± 4.1
82.6± 3.2
87.6± 3.1
79.9 ± 4.4 81.0± 3.4
Sleep
62.6 ±
8.5
64.0± 1.0 90.9 ± 4.0
84.4+ 3.1
Men
Women
89.1 ± 6.8 72.3 ± 5.2 84.0 ± 11.3
88.8 ± 4.9
80.5 ±
Period of Day Before work Morning work Exercise " h o u r " " Afternoon work
10-hr, average
8I.4±
3.1
85.6± 2.9
Daytime average
80.8 ±
3.5
83.5 ± 2 . 7
24-hr, average
76. l ±
2.2
78.6 ± 2.1
"Satisfactory data obtained on only 5 men and 4 women using SAMI & 5 men, 5 women using tape-recorder.
Table 6. Frequency Distribution of Heart-Rate for Specified Periods of the Day. Data Obtained from Tape-Recordings of the ECG (Minutes in Specified Frequency Range, Mean± S.E.).
Period of day
120 Beats/Min
M
F
M
F
3
28 ± 5
17± 6
30±5
8± 5
Afternoon workt
175 ± 21
222± 10
35 ± 10
29 ± 9
15±6
ll±6
Evening leisure!
2I2± 31
262 ± 18
42± 16
27 ± 10
10±2
9±5
Exercise "hour"*
•M=5, F=5 tM= 6. F= 8
I9±
7
9±
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Somewhat surprisingly, there was a negative correlation between the reported minutes active per day and the directly measured aerobic power (r = -0.68 for the men (N= 11), -0.63 for the women (N = 10): Heart rate measurements. — Average SAMI heart rate readings (Table 5) were remarkably low for all segments of the day, including the "exercise hour." Among the female subjects, there was a fair concordance of SAMI and taperecorded data for afternoon work and evening leisure. However, the SAMI cells necessarily included in their average time spent in travelling to and from the sports field, changing, and sitting awaiting the commencement of formal instruction. In the male subjects, the SAMI apparatus yielded consistently lower heart rates than the tape-recorded values. The discrepancy is rather large to attribute to a few differences in the subjects tested by the two methods and probably reflects undetected faults of electrode contact during use of the SAMI equipment; obvious contact problems led to rejection of electro-chemical integrations for three of the 12 subjects during the exercise session. However, if the apparent heart rate falls within a plausible range, there is no basis for rejecting data (Edholm, Humphrey, Lourie, Tredre, & Brotherhood, 1973). The tape-recorded rates
30
SIDNEY AND SHEPHARD their fitness prior to entry into the exercise program, what is the situation of other groups such as senior citizens clubs, homes for the aged, and geriatric wards? Comparisons may be made in terms of total caloric expenditures, reported activities, and heart rate measurements. The over-all caloric expenditures of our volunteers can be calculated from Tables 2 and 3, using standard values for the energy cost of the various tasks listed (Durnin & Passmore, 1967; Sidney, 1975). The data show that relative to other elderly groups, the augmentation of daily energy expenditure (150-200 kCal/day) at least equalled the net cost of the exercise "hour." In the men, the average daily total (2500 kCal) was comparable with the young office-worker (2520 kCal, Durnin & Passmore, 1967), not much less than the figure for older men in light industry (2684 kCal, Durnin, Blake, Allan, Shaw, Wilson, Blair, & Yuill, 1961), and substantially greater than that commonly encountered in retired (2330 kCal, Durnin & Passmore, 1967)and institutionalized men (2116 kCal, Salvosa, Payne, & Wheeler, 1971). Among the women, our daily totals were similar for the employed (2264 kCal) and those recently retired (2212 kCal). Figures were comparable with those for young University students in Scotland (2290 kCal, Durnin & Passmore, 1967) and young salesgirls (2255 kCal, Durnin, Blake, & Brockway, 1960), but substantially greater than data for elderly housewives with families (2113 kCal, Durnin, 1966), elderly housewives living alone (1987 kCal, Durnin, 1966), retired women living at home (1700 kCal, Salvosa et al., 1971), and institutionalized women (1566 kCal, Salvosa et al., 1971). We may thus conclude that if our subjects were initially taking insufficient physical activity to sustain fitness, this is even more true of other segments of the elderly population. The results also suggest that an exercise hour sufficient to induce cardio-respiratory training can be added to the day without bringing about compensatory decreases in other forms of vigorous activity; indeed, over the year of observation, our subjects apparently initiated some beneficial changes in activity patterns at other times during the day, including a decreased use of their cars. Few previous studies give detailed descriptions of daily activities in the elderly. Relative to young men (Edholm, 1967; Shephard, 1967), our old subjects spent more time on walking
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activity (Durnin, 1967; Cunningham et al., 1969). The individuals concerned also thought that they were more active than the general population of their age. Nevertheless, the data for cardio-respiratory fitness (Sidney, 1975) suggest that on entry to the program activity levels were far from sufficient to realize their genetic potential. At the initial appraisal, maximum oxygen intake (23.5 ml/kg/min in the men, 23.4 ml/kg/min in the women), excess weight (9.3 kg in the men, 8.1 kg in the women) and average skinfold thickness (16.2 mm in the men, 21.1 mm in the women) were no better than in other Canadian city-dwellers of the same age (Bailey et al., 1974; Shephard, 1969). Further, 3 mo. of endurance training sufficed to increase aerobic power by as much as 30%. The paradox of perceived activity but low fitness levels can be explained in several ways. It may be that a person who is unfit takes longer to perform a physical task and finds it fatiguing, thus convincing himself that he is working hard; in support of this view, we found the rating of perceived exertion (Borg, 1971) to be 3 to 4 units higher at any given heart rate than would be the case in young (Sidney, 1975; Skinner, Hutsler, Berg^ y , g steinova & Buskirk, 1973). Societal expectations also diminish with aging; a recent survey from the USA showed that while few old people were taking any deliberate exercise, 71% of those over the age of 60 considered that they took sufficient activity (Clarke, 1974). The base-line for comparison is extreme inactivity. Statistics Canada (1972) reported that people over the age of 65 years led the rest of the nation in watching more than 4 hours of television per day, with less than 9% of those over the age of 55 taking any deliberate exercise. Any activity that is undertaken is typically gentle walking rather than vigorous sport, and the vigor is rarely sufficient to reach the threshold where a training effect could be anticipated (Cunningham et al., 1969). Even in the elderly, cardio-respiratory training is unlikely unless a heart rate of 120/min is surpassed for several minutes (Shephard, 1968). It is thus not surprising that there was no relationship between the initial perceived activity of our exercise volunteers and objective measurements of their endurance fitness. Activity patterns of other elderly populations. — Given that our sample of volunteers were not taking enough activity to maintain
AGE AND ACTIVITY
Table 7. Previously Reported Average Heart Rates.
Subjects Middle-aged men Policemen Men aged 16-70 (no age differences) Men Type A Men Type B
Work
Active Leisure
Sleep
84
85
67
86-94 71-106
83-85 71-106
64-68 48-80
86 85
83 79
71 66
Note: Authors: Richardson (1971); Goldsmith & Hale (1971); Glagov et al. (1970); Friedman et al. (1963).
to 1.38 per 100. Those following good health practices including regular physical activity had a health status (measured in terms of hospital admissions and medical consultations) equivalent to the general population who were 30 years younger (Belloc & Breslow, 1972). A similar study by Palmore (1970) showed that more than four times as many inactive subjects reported poor health as those who were engaged in regular physical activities. While all of these studies are suggestive of a health benefit from an increase of physical activity, they do not exclude the possibility that poor health may have influenced the initial decision not to take physical activity in at least a proportion of those who were inactive. The longitudinal experience with our sample of elderly subjects showed significant gains in perceived health in response to training (Sidney & Shephard, 1976a). However, a categorical answer to the question of health benefits must await a much larger longitudinal study in which fitness and activity levels are correlated with objective measures of health experience. SUMMARY
Questionnaires on past and current participation in physical activity were given to 13 men and 21 women aged 60 years and over who had volunteered for a program of endurance training. Additional information was collected by 7-day and 24-hour prospective diaries, along with measurements of heart rate made by SAMI electrochemical integrator and taperecorder. Volunteers were either retired or engaged in sedentary occupations and their leisure pursuits also were initially inactive, data from the diary records and heart rate counts being confirmed by objective measures of physical fitness. Nevertheless, the subjects thought that they were more active than others of their age. Explanations of this paradox are discussed. Outside of the exercise hour, activity patterns were much as reported in previous surveys of elderly working subjects. During the week, the women engaged in 90 min. more activity than the men, but at the weekend the men added an average of 100 min. of physical activity, while the women engaged in 30 min. less physical activity than on weekdays. At different periods of the day, the heart rate averaged 70 to 90 beats/min., and heart rates where cardio-respiratory training might be anticipated were rarely encountered. The exercise hour apparently augmented the daily caloric expen-
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and less on sitting. The women spend substantially less time lying than previous samples of Scottish ladies (509, 510, and 581 min., Durnin etal., 1960, 1961; Durnin, Blake, Brockway, & Drury, 1961). Our employed ladies also spent less time on housework than the Scottish sample, but this reflects their career rather than the . availability of domestic appliances, since figures for our retired women were comparable with those seen by Durnin and his associates. In contrast to our data, Durnin's elderly women spent relatively little time walking (66, 66, and 45 min.), and he comments (Durnin, 1964; 1969) that the main effect of aging was a 45-min. diminution in walking per day. Our experience with the two methods of heart-rate counting confirms the general conclusion of International Biological Programme Investigators (Shephard, 1976) that the taperecorder is more satisfactory than the SAMI equipment. Nevertheless, SAMI figures for periods other than the exercise hour seem generally comparable with those reported in the literature (Table 7). If the training threshold at this age is a heart rate of 120/min., our subjects were getting a maximum stimulation of 30-40 min. per day, excluding their exercise hour; much of this time could of course be discounted, since the tachycardia was commonly caused by emotion or isometric effort rather than by aerobic stress. In agreement with Glagov, Rowley, Gramer, & Page (1970), 80% of waking values were less than 10 beats per minute higher than those encountered during sleep! Health significance of activity. — How important is it to health that the elderly become more active, realizing their fitness potential? Hammond (1964) found death rates to show a gradation with activity; in men aged 60-64 years, the range was from 4.9 per 100 in those taking no exercise to 0.92 in those taking regular heavy exercise, while in those aged 65-69 years the gradient was even steeper, from 10.33
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diture by 150-200 kCal, totals (2500 kCal for the men, 2200 kCal for the women) being substantially larger than in previous studies of elderly desk workers. The added exercise was sufficient to improve both aerobic power and body composition over the year of observation. Further, the program of endurance activity apparently had some carry-over into other areas of life style, notably a diminished use of the car by the men.
134, 1214-1200.
Milne, J. S., Maule, M. M., & Williamson, J. Method of sampling in a study of older people with a comparison of respondents and non-respondents. British Journal of Preventive or Social Medicine, 1971, 25, 37-41. Palmore, E. Health practices and illnesses among the aged. Gerontologist, 1970,70, 313-316. Salvosa, C. B., Payne, P. R., & Wheeler, E. F. Energy expenditure of elderly people living alone or in local authority homes. American Journal of Clinical Nutrition, 1971,24, 1467-1470. Shephard, R. J. Normal levels of activity in Canadian city dwellers. Canadian Medical Association Journal, 1967, 97, 313-318. Shephard, R. J. Working capacity of selected populations. In J. Weiner (Ed.), /. B. P. Synthesis, Vol. 4, Human Adaptability Project. University Press, Cambridge, 1976. Shephard, R. J. Intensity, duration and frequency of exercise as determinants of the response to a training regimen. Internationale Zeitschrift fur angewandte physiologie, 1968, 26, 272-278. Shephard, R. J. Endurance fitness. University Press, Toronto, 1969. Sidney, K. H. Responses of elderly subjects to a program of progressive exercise training. PhD Thesis, Univ. Toronto, 1975. Sidney, K. H., & Shephard, R. J. Attitudes towards health and physical training programme. Medicine & Science in Sports, 1976. (in press) Skinner, J. S., Hutsler, R., Bergsteinova, V., & Buskirk, E. R. Perception of effort under different types of exercise and under different environmental conditions. Medicine & Science in Sports, 1973,5, 110-115. Statistics Canada. Survey of physical activity, 1971. Preliminary findings reported in Medical Post, July, 1972. Weiner, J., & Lourie, J. A. Human biology. A guide to field methods. Blackwell, Oxford, 1969. Wolff, H. S. Physiological measurements on human subjects in the field, with special reference to a new approach to data storage. In H. Yoshimura & J. S. Weiner (Eds.), Human adaptability and its methodology. Society for the Promotion of Sciences, Tokyo, 1966. World Health Organization. Energy and Protein Requirements. Report of a joint FAO/WHO ad hoc expert committee. Technical Report. 522, (Geneva), 1973. Zborowski, M. Aging and recreation. Journal of Gerontology, 1962, 17, 302-309.
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