Journal

c~f Psvchowmarir

Rexwrch.

Vol.

35.

1991.

No. 415. pp. 437-449,

0521-3999191

THE EFFECTS PSYCHOLOGICAL SYLVIA (Received

.$3.00+

00

% 1991 Pergamon Press plc

Prmted in Great Bntam

R.

OF MODERATE EXERCISE TRAINING ON WELL-BEING AND MOOD STATE IN WOMEN CRAMER,

29 March

DAVID

C.

1990; accepted

NIEMAN

and JERRY W.

in revised form

6 November

LEE 1990)

Abstract-The relationship between moderate exercise training (five 45 min sessions/week, brisk well-being and mood state was investigated walking at 62 R f 2 % VO,,,, for 15 weeks, psychological in a group of 35 sedentary, mildly obese women. A 2 (exercise (EX) (N = 18), and nonexercise (NEX) (N = 17) groups) x 3 (baseline, 6-week, 15.week testing sessions) factorial design was used with data analyzed using repeated measures ANGVA. Four psychological tests were administered: Daily Hassles Scale (DHS), General Well-being Schedule (GWB), Spielberger State Anxiety Inventory (S-Anxiety), and Profile of Mood States (POMS). The EX and NEX groups had significantly different patterns of change over time for GWB total scores [F(2,66) = 5.72,~ = 0.0051 and the GWB subscales ‘energy level’ and ‘freedom from health concern or worry’. Scores for the EX group were elevated at both 6 and 15 weeks. General well-being total scores and subscale ‘energy level’ scores were significantly correlated with improvement in submaximal cardiorespiratory fitness (r = -0.41,~ = 0.014; r = -0.40,~ = 0.017, respectively). Exercise training also had a significant effect on frequency but not intensity of DHS scores, and S-Anxiety, with a significant decrease seen in the EX group at 6 weeks but not 15 weeks. Profile of Mood States scores were not significantly related to exercise training. These data support the results of other studies that have reported improvement in general psychological wellbeing with exercise training.

INTRODUCTION RELATIONSHIP between exercise and psychological health has been widely researched with several reviews available [l-61. In general, reviewers have concluded that although poor study design often makes interpretation difficult, results suggest improvement in mood state with exercise training. Results from most cross-sectional 17-l 11 and quasi-experimental 112-161 studies suggest that exercise training enhances mood state. Among the principle findings concerning the relationship of physical activity to mental health are reduced symptoms of anxiety 110, 12, 14-161 and depression 17, 8, 10, 12, 13, 15, 161, and increased well-being [ 10, 111. A recent review of four independent national surveys 1111 from the general non-institutionalized population revealed that physical activity was positively associated with general well-being in all age and gender subgroups measured. This relationship was particularly evident in women. Results from another crosssectional community survey 1101 also showed that participation in exercise, sports and physical activities was associated with improved psychological well-being. However, findings from randomized studies are less impressive 117-241. One critical review 133 of 12 randomized controlled experiments failed to find support for the role of exercise training in improvement of anxiety, depression, body image, personality or cognition. However, subjects from nearly all of the studies included THE

Department of Health Science, School of Public Health, Loma Linda University. Author to whom correspondence should be addressed: David C. Nieman, DHSc, MPH, FACSM, Department of Health, Leisure, and Exercise Science, Appalachian State University, Boone, NC 28608, U.S.A. Supported by a grant from the Steele Foundation. 437

438

S. R. CRAMER et nl.

in this review came from clinical or non-adult populations. In a randomized, crossover trial utilizing psychologically healthy, sedentary men, 12 weeks of treadmill walking and stair climbing failed to improve mood state [20]. Blumenthal et al. [24] were also unable to demonstrate that four months of aerobic activity by elderly subjects significantly improved psychological measures in comparison to control groups (yoga and flexibility, or a waiting list). On the other hand, Long [211 concluded that both aerobic training and stressinoculation training were effective in reducing self-reported anxiety relative to a waiting list control group among community residents who felt they needed help in coping with stress. Moses ef al. t221 and Steptoe et al. [23] have reported that tension-anxiety measures were reduced in adult community volunteers (primarily women) who engaged in moderate aerobic exercise (walk-jog) for 10 weeks relative to an attention-placebo condition (flexibility-strength calisthenics). However, changes over time were modest, and no significant differences were apparent for most other mood state measures. Thus data from randomized trials on the effects of exercise training on mood and mental well-being are not consistent, and further research is warranted. Moses et al. [221 have reported that moderate exercise (30-40 mitt, 60% maximal heart rate, three sessions/week) is preferable to higher intensity exercise (70-75% maximal heart rate) in reducing tension-anxiety, and is not accounted for by nonspecific factors such as selection, expectations, or attention. These researchers also concluded that psychological benefits may not be directly related to improvements in maximal aerobic capacity per se. Brisk walking for exercise is now one of the fastest growing activities in the United States [251. Walking, a low- to moderateintensity physical activity, has been found to have a higher compliance rate than other activities, because it can easily be incorporated into a busy time schedule, does not require any special skills, equipment, or facility, is convivial, and is much less apt to cause injuries. The purpose of the present study was to investigate whether a relationship between psychological mood state and moderate exercise training would emerge in mildly obese women undergoing a 15-week walking program, when a randomized design was employed with an assessment-only control condition. METHODS Subjects

Subjects were recruited from the local community within a 15 mile radius from the School of Public Health at Loma Linda University. Flyers and newspaper advertisements in the surrounding area generated over 800 inquiries for the research study. Selection criteria for the inclusion of subjects were: 25-45 yr of age, female, mildly obese (lo-40% overweight), premenopausal, 1.57-l .73 m in height, not presently on an exercise program or reducing diet, non-smoker without a history of alcohol or drug abuse, presently not taking medications (except for oral contraceptives), and the absence of hypertension, diabetes or other known metabolic disease. Subjects additionally agreed to accept random assignment to either the experimental or control group and voluntarily signed an informed consent statement approved by the Loma Linda University Review Board for Human Studies.

Experimentuidesign A two (EX and NEX) by three (three testing sessions) factorial design was used for this investigation. Fifty subjects selected for the research study were randomly assigned to the EX or NEX group. The testing schedule consisted of baseline, 6-week and 15.week measurements. The EX group was tested one week prior to the NEX group at each time point. Testing started in mid-January and was concluded in May 1989. The psychological testing was conducted on the Wednesday evening before the Sunday testing, which included the body composition and metabolic tests.

Exercise

training

and psychological

states

439

A general orientation meeting was held for the subjects 11 days prior to the beginning of the study. At this time, four psychological tests were administered in the following order: Daily Hassles Scale (DHS); General Well-being Schedule (GWB); Spielberger State Anxiety Inventory (S-Anxiety); and the Profile of Mood States (POMS). An investigator read each set of directions aloud while subjects read silently. Subjects were informed their responses would be confidential and test results given at the completion of the study. This baseline data was collected prior to the disclosure of the group each subject was randomly assigned. Subjects were not informed as to the purpose of the psychological tests, nor were expectations regarding the effect of aerobic training on tests scores explained or verbalized. Personal daily logbooks were given to each subject for recording exercise type, duration and distance and any health problems encountered throughout the 15week study. All subjects were instructed not to go on a reducing diet during the 15-week study and NEX subjects were told to remain sedentary. For the Sunday testing, all subjects reported to the Human Performance Laboratory for anthropometric measurements and graded exercise testing. Body density was determined by hydrostatic weighing, as outlined by Pollock ef al. [261, using the formula of Siri [271 to determine percentage of body fat. Residual lung volume was determined with the Jaeger constant volume, variable pressure plethysmograph (Erich Jaeger GmbH. and Co., Wurzburg, F.R.G.). A 12-lead EKG was recorded at rest and throughout the treadmill test. The graded exercise test was carried out utilizing the protocol by Bruce et al. [281 with the Quinton Q4000 stress test system and Q55 treadmill (Quinton Instrument Co., Seattle, WA, U.S.A.). Oxygen uptake and ventilation were measured using the Sensor Medics MMC Horizon System 4400 metabolic cart (Sensor Medics, Anaheim, CA, U.S.A.). Heart rate, ventilation and oxygen uptake were recorded during the last 15 set of each stage. Stage 2 heart rate was used as a measure of improvement in submaximal cardiorespiratory fitness. Psychological data was additionally obtained at 6.week and 15-week intervals, four days before the treadmill and body composition testing, and was administered as previously described for the baseline procedure. No morning exercise session was held on the day of the psychological testing so that a minimum of 23 hr had elapsed since the last exercise session for the EX group. All participants in the EX group walked after the evening psychological testing session. Body composition and metabolic data was also obtained at 6. and 15.weeks on Sunday as described above.

Subjects in the EX group walked 5 days/week, 45 minIsession for 15 consecutive weeks. Training heart rates were calculated based on 60% of the heart rate reserve measured at the baseline testing and were recalculated based on each subject’s performance at the 6-week treadmill testing. Exercise sessions took place on a measured course near the research testing facility. To accommodate daily schedules, subjects selected either a morning (6.30-7.15 a.m.) or an evening (5.45-6.30 p.m.) exercise session. Each exercise session was conducted by an exercise supervisor who monitored and recorded each subject’s heart rate and distance traveled. Ten-second pulse counts or heart rate monitors were utilized to ensure that each subject trained at the appropriate calculated training heart rate. In the event of minor injuries, subjects continued to exercise using the stationary bicycle ergometer. When subjects missed training sessions due to illness, injury or vacation additional sessions were supervised during the weekend by the exercise leader.

The Daily Hassles Scale [291 consists of 117 items designed to measure the frequency and intensity of a person’s transactions with the environment that are considered by the individual to be stressful events. Subjects indicated the occurrence of each hassle in the previous month and rated each hassle on a three-point scale as having been ‘somewhat. ‘moderately’ or ‘extremely’ severe. The General Well-being Schedule (GWB) [301 consists of I8 items which generates a total GWB score and six subscale scores which include freedom from health concern, energy level, satisfying life, cheerful-depression, tension-relaxation and emotional stability. Subjects answered each question based on how they generally felt during the past month. A high score on the GWB represents an expression of positive well-being and the absence of bad feelings. The Spielberger S-Anxiety Inventory L3 11 consists of 20 items designed to assess state anxiety. The test directions were modified to evaluate how the subjects felt during the past week, rather than ‘right now’. The POMS [321 consists of 65 adjectives rated on a five-point scale designed to assess the following six mood or affective states during the previous week: tension-anxiety; depression-dejection; angerhostility; vigor-activity; fatigue-inertia; and confusion-bewilderment. In addition, the POMS global (total mood disturbance) score was used to obtain an overall measure of affective state. The global score

440

S. R. CRAMER er al.

was calculated from the raw scores by subtracting the vigor score from the sum of the negative of affect and adding a constant of 100 to eliminate negative values.

measures

Statistical analysis

Results are expressed as mean I3+ SE. A 2 x 3 repeated measures ANOVA with one between-subjects factor (EX vs NEX) and one within subjects factor (time of measurement) was used to analyse the data. When Box’s M suggested that the assumptions necessary for the univariate approach were not tenable the multivariate approach to repeated measures ANOVA was used [331. In the latter case Pillais’ trace statistic was used as the test statistic, since it seems most robust when assumptions are violated [341. With regard to comparison among specific means only seven comparisons were of interest to us. These were the contrast of the baseline measures with the 6-week and the 15.week measurements within the EX and NEX groups and the contrast between the EX and NEX groups at each of the three measurement points. The Dunn-Sidak procedure I341 was used to test these comparisons. Pearson correlations were used to determine the association between changes in psychologic and metabolic measurements.

RESULTS

Subjects Thirty-five of the 50 women originally selected for the study complied with all phases of testing and intervention. There were seven dropouts from the EX group, eight from the NEX group. Four (two from each group) did not attend the orientation meeting, four others (one EX and three NEX) for personal reasons dropped out prior to baseline testing, and seven others (four EX and three NEX subjects) started but failed to complete all phases of the study. Evaluation of baseline psychological tests revealed no significant differences between study participants and dropouts nor were subjects remaining in the EX group significantly different from subjects remaining in the NEX group. Dropouts did not differ from study participants in body mass index (BMI) (kg/m*) but were significantly younger (30.6 + 1.2 and 34.2 +_ 1.1 yr respectively, p < 0.05). Age averaged 36.0 + 1.6 and 32.4 + 1.5 yr for EX and NEX groups respectively; BMI averaged 28.3 + 0.7 and 27.8 + 0.9 for EX and NEX groups respectively (NS). Training program Each of the 18 subjects in the EX group complied completely with the exercise regimen as previously outlined. All NEX subjects remained sedentary for the duration of the study as verified through evaluation of data recorded in their personal daily logbooks. Ninety percent of all exercise sessions for EX subjects were supervised. During the first six weeks, EX subjects averaged 5.0 f 0.1 km/session, and during the remainder of the study, 5.1 k 0.1 km/session. Measured exercise heart rates averaged 138 _+ 1 bpm which corresponded to 60% heart rate reserve or 62 + 2 % V02max. Body composition

and metabolic

parameters

Table I summarizes the metabolic and body composition values for both EX and NEX groups at baseline, 6, and 15 weeks. The pattern of change in total body weight but not body fat percentage, was significantly different between EX and NEX groups, with NEX subjects experiencing a 2.3 + 0.7% gain in weight. The body composition data are being presented elsewhere. Data from the graded exercise testing revealed significant improvement in both heart rate and ventilation measurements during stage 2 for EX subjects. The majority

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