METABOLIC ADJUSTMENTS TO MARATHON RUNNING IN CORONARY PATIENTS* Rudolph H. Dressendorfer,? Jack H. Scaff, Jr., John 0. Wagner, and James D. Gallup Department of Physiology University of Hawaii School of Medicine Honolulu, Hawaii 96822 Honolulu Medical Group Honolulu, Hawaii 96813
How well do trained heart patients respond to the physiological demands of marathon running? As part of a long-range project investigating the efficacy of longdistance running ( 2 10 km) in the treatment and prevention of coronary artery disease, the present study was undertaken to quantify physiological adjustments of five trained coronary patients to running the 1974 Honolulu Marathon (42.2 km). The study provides supportive and additional data on the above question regarding the physiology and safety of marathon running by myocardial infarct patients.' Reported findings include cardiorespiratory, thermal, biochemical, and metabolic measurements made before, during, and after the marathon run. PATIENTS AND METHODS Subjects
Five moderately to well trained middle-aged men were selected from volunteers in a group of coronary patients who had undergone 6 months of marathon training. On the average, these subjects were quite typical of patients in our cardiac rehabilitation program who show improvement with physical conditioning. The selection was made to provide a range in type and severity of coronary artery disease on the basis of diagnostic tests made one year earlier. A description of subjects is presented in TABLE1. Subject 1 showed electrocardiographic signs of ischemia with chest pains during maximal treadmill stress testing and was presumed to have coronary artery disease. Subjects 2-5 had healed myocardial infarcts (MI), which occurred 1.5 to 4 years before the race. The MISwere diagnosed and quantified with electrocardiographic changes,
* This work was supported in part by a grant from the Honolulu Medical Group Research Foundation. t Present address: Human Performance Laboratory, Department of Physical Education, University of California at Davis, Davis, Calif. 95616. 466
Dressendorfer et al. : Effects on Coronary Patients
467
serum enzyme levels, angiograms, and vectorcardiography. Subject 5 underwent surgical bypass revascularization of three coronary arteries 1 year before the race. TABLE 1 also shows measurements of average skinfold thickness, resting pulse rate, and blood pressure. Percent body fat, predicted from triceps, subscapular, and umbilical skinfolds,2 averaged 18.7 % Subject 4, estimated as 32% fat, was classified obese despite a substantial weight loss during training. Subject 3 was a finisher in the 1973 Honolulu and 1974 Boston marathons. Smoking and alcohol consumption had been discontinued for about 1 year. TABLE 2 shows fasting serum levels for cholesterol, triglycerides, uric acid, glucose, sodium, and potassium as determined 2 weeks before the race. Mean values were within the clinical range of normal. Before exercise reconditioning, subject 5 had serum cholesterol and triglyceride levels of 344 and greater than 1200 mg/dl, respectively. In the month preceding the marathon race, training distance for the group averaged 60 to 75 km-wk-l at a mean velocity of about 150 m-min-l. Subject 1, however, consistently averaged 140 km.wk-1, whereas subjects 4 and 5 were bothered by minor leg injuries that prevented their training mileage from increasing beyond a level of 60 kmewk-l. Longest training runs before the race were 25 to 30 km. During these long runs no subject experienced angina pectoris.
.
Design of Experiment
(vo,)
Measurements of oxygen uptake and heart rate (HR) were made 1 to 3 weeks before the race during road running tests at various velocities to a maximum. The observed relationships between Po, and running velocity and to,and HR for each subject were subsequently used in estimating during the race. Fifteen days before the race, each subject performed a 15-minute treadmill run at 80%-85% of his highest observed HR (HR,,,) while respiratory metabolism and the electrocardiogram (ECG)were obtained. Determinations of systolic time intervals (STI) , measured in the supine position, were made before and approximately 5 minutes postexercise. In addition, rectal temperature (T,) was measured and blood and urine were collected before and 5 to 10 minutes after the treadmill run. Urine samples and body weights were taken within 10 minutes before the race. During the race each subject was accompanied by a cardiac nurse who bicycled alongside. Whenever the subject stopped to consume fluids, the nurse palpated his pulse and recorded time, place, and quantity of fluid consumed. Immediately after completing the race, the subject was escorted to an air-conditioned room located 100 m from the finish line where body weight, T,,, and blood and urine samples were obtained within 10 minutes. The subject then performed a second treadmill test at the target HR level obtained in the first treadmill test. Respiratory metabolism, ECG, and recovery STI were determined as before.
vo,
175
43
47
47
46
3*
4
5
Mean 65.1
62.1
77.9
60.4
62.1
56.9
Weight (kg)
59
68
54
64
60
~~
(>2 mm) during treadmill stress test; presumed coronary artery disease (1 yr) 3 4 cm antedor transmural MI with dyskinetic segment and presumed ventricular aneurism (4 Yr) 4-5 cm inferior transmural MI (2yr) 4-5 cm inferior transmural MI (2 yr) MI (1.5 yr); triple bipass aorto-coronary transplant (1 yr) 4 patients post-MI, 1 patient asymptomatic
S-Tsegment depression
History of Coronary Disease (years before marathon race)
thigh.
t Unweighted average skinfold thickness measured at seven sites: triceps, subscapular, suprailiac, umbilical, chest, axillary, and front
121/79
100/70
130/84
140/84
128/84
108/72
50
-
Sitting Blood Pressure (mmHg)
Sitting Pulse Rate (b m i d )
t Completed two previous marathon races (42.2 km) within preceding year.
15.8
18.7
26.2
8.4
11.7
14.2
Subcutaneous Fat t (mm)
* Measurements made two weeks before marathon race.
171
170
175
168
45
2
169
Height (cm)
48
Age (yr)
1
No.
Subject
TABLE 1 DESCRIPTION OF SUBJECTS*
P3
w
b
s
P
469
Dressendorfer et al. : Effects on Coronary Patients Measurement Techniques
Field testing to determine the energetics of road running was conducted along a flat, approximately 800 m circuit after the subjects had completed training runs of 10 to 15 km. The subject ran 1 m beside a car at self-paced running velocities up to a voluntary maximum. At each velocity, expired gas was collected in a 200-liter meteorological balloon over the second 400 m using portable respiratory equipment designed for this p ~ r p o s e Duplicate .~ gas samples were drawn in glass syringes and measured for 0, and CO, concentrations with a micro-gas analyzer (Scholander, Rutledge, Pa.). Gas volume and temperature were measured after each run in a gasmeter (Type CD4, ParkinsonCowan, Blue Bell, Pa.). Maximal 0, uptake (3,,1,,,,,)was defined as the highest Vo, observed, which typically leveled off at maximum velocities. Exercise HR was estimated by timing 15 carotid pulses in the immediate recovery. TABLE 2 FASTING SERUMLEVELS*
Uric Subject Cholesterol Triglycerides Acid No. (mg/dl) (mg/dl) (mg/dl) 1 2 3 4 5
Mean
215 185 250 305 205 232
90 196 83 100 273 150
8.2 6.7 5. I 5.9 8.8 6.9
Glucose (mg/dl)
Na (meq/l)
(meq/l)
109 120 103 122 105 112
142 146 147 145 143 145
4.1 4.6 4.8 5.0 5.3 4.8
K
'! Blood samples taken 2 weeks before marathon race, 12 to 16 hours after eating,
with the subjects being well rested.
Zero grade was used in both treadmill tests. Expired gas was collected and analyzed as discussed above. Heart rate was determined from the ECG obtained using bipolar chest leads placed in the V, and manubrium positions. STI values before and after exercise were measured according to the method and procedures described in detail by Maher et al:' Body weight was measured on a platform scale accurate to k 5 0 g. Sweat loss during the race was estimated from changes in body weight after correcting for fluid intake and respiratory weight losses.5 Fluid intake, which included water and sundry solutions of sugar and electrolytes, was measured by using containers of known volume. Rectal temperature was measured with a mercuryin-glass thermometer inserted 8 cm. Blood samples were drawn by syringe from an antecubital forearm vein at rest before and then 8 to 10 minutes following the first treadmill test, and also 8 to 10 minutes after the race. Technical difficulties precluded blood sampling before the race. All determinations were made on serum except for
470
Annals New York Academy of Sciences
hematocrit (Hct), hemoglobin (Hb), and lactate, which were made on whole blood. Analysis for total protein, albumin, cholesterol, calcium, inorganic phosphorous, glucose, creatinine, uric acid, total bilirubin, alkaline phosphatase (Enzyme Code 3.1.3.1), lactate dehydrogenase (LDH, E.C. 1.1.1.27), and aspartate minotransferase (GOT, E.C. 2.6.1.1 ) were performed on a sequential multiple automatic analyzer (Type 12/60, Technicon Instruments Corp., Tarrytown, N.Y.). Hct, calculated as mean corpuscular volume times red blood cell count, and Hb were determined with a cell counter (Model S, Coulter, Hialeah, Fla.). Lactate was analyzed by the enzymatic method using a commercially available test kit (Sigma Chemical Co., St. Louis, Mo.). Osmolality was determined by freezing point depression. Triglycerides were measured by a fluorometric procedure.6 Sodium, potassium, and magnesium were determined by atomic absorption. Alphahydroxybutyrate dehydrogenase (a-HBDH, E.C. 1.1.1.27) was determined with a commercial test kit (Boehringer, Indianapolis, Ind.). Creatine phosphokmase (CPK, E.C. 2.7.3.2) was analyzed according to Rosalki.7 AU serum enzyme determinations were done spectrophotometrically at 25°C by measuring either the appearance or disappearance of NADH or NADPH. A full report on the methods and results of urine analysis will be published elsewhere. Marathon Race The subjects were among 19 cardiovascular patients who completed the 1974 Honolulu Marathon, a certified road course measuring 42,195 m. Most of the course was flat, but a hill 38 m in vertical elevation had to be climbed at 8.4 km (average grade of 2.4% for 1400 m) and again at 36.9 km (average grade of 1.0% for 3000 m). Thus, hill-running on two gradual slopes comprised 20% of the race. The course record as of 1975 was 2:17.24 (J. Foster, New Zealand). Ambient conditions at the start (6:30 AM) to when the last subject finished (12:40 PM) ranged as follows: T,,,22" to 28°C; RH, 79% to 58%; wind velocity, 3.6 to 6.7 m-sec-l; cloud cover, about 50%. Runners were resisted by an average 4.0 m-sec-l headwind for 7.5 km and aided by an equally strong tailwind for 3 km. Physicians and nurses were available at 11 first aid and refreshment stations along the course beginning at 5 km. RESULTS Subjects were numbered according to their sequence of finishing the race. 0, Uptake during Road Running
vo,
FIGURE 1 shows curves relating (mlekg-l mmin-l) to running velocity (mamin-1) for each subject. Oxygen uptake was a linear function of velocity before plateauing at an apparent mar, which averaged 2.66 litersmin-l (41.3
v0,
Dressendorfer et al.: Effects on Coronary Patients
47 1
ml*kgl*min-l). Regression analysis of grouped data excluding points after po2began leveling off resulted in the least squares best fit equation: Po?= 0.158 (velocity) 6.0. This relationship had a highly significant correlation coefficient of 0.97. Although resting Vozwas not used in the linear regression analysis, the value of 6.0 ml-kg1.min-1 at the y intercept approximated standing Po, prior to running. Individual curves relating HR to Voa are shown in FIGURE 2. Peak values for HR averaged 176 b.min-l. For subjects 1, 3, and 4 only, ~ O z m n rwas also measured during uphill treadmill running and results were within +3 ml.kg1.rnin-1 of their road running values.
+
55
-
1
I
I
cz
X
-.
40-
E
u
X
g
35-
3 E 0
5
30-
0
25
1
4
3
120
I60 Road
200 Running
240
280
320
Velocity, m.min-'
FIGURE 1 . Relationship between road running velocity and Oa uptake in five coronary patients. Subject numbers are shown in parentheses. Arrows indicate average velocity during the marathon race. Observations during the Marathon Race
Observed and derived data for each subject are presented in TABLE3. Finishing times averaged 299 minutes and ranged from 205 to 370 minutes. Estimation of V ,
Running velocity was determined at 7 to 10 locations on the course and averaged 147 m-min-l. For descriptive purposes, the race was arbitrarily subdivided into the following three stages: start to 16 km, 16 to 32 km, and 32
Annals New York Academy of Sciences
472
3.0
2.5
-
-E C
X 0
0 c
3 2.0 C
V
F
0
1.5 //
I
130
,
I
I40 Heart
150
I
I60
I
I70
, 180
R a t e , barnin-'
FIGURE 2. Relationship between heart rate and the O1 uptake during road running 1. Arrows indicate average heart rate for each subject during the shown in FIGURE marathon race.
voz,
km to finish. FIGURE 3 shows velocity, HR, and % Po2mnx for each stage. Average velocity for each stage was 156, 149, and 129 m-min-', respectively. From the start to 16 km, to,was 30.7 ml.kg'.min-l and H R averaged 150 b-min-l. The hill climb at 8.4 km increased HR to 163 b-min-l, which predicted a of 2.53 liter.min-' (39.2 ml.kg1.min-') or 95% of If we assume the runners maintained their velocity, the predicted is very similar to that observed in treadmill studies.* Uphill running, therefore, increased the average Po, for this stage to 31.4 ml.kg-l.min-l. From 16 to 32 km, was 29.5 ml*kg-'.min-l while H R was 141 barnin-'. During this part of the race, however, the subjects were confronted by a steady 4.0 m.sec-l headwind for 7.5 km, which according to Pugh@should have increased 3, by 0.14 liter-min-' to about 31.6 ml-kg-min-'. Thus, the adjusted average for this stage was 30.4 ml.kgl.min-l. Except for subject 2 who maintained his pace, average velocity decreased
coz
vo2mnx. voz
co2
vo2
Dressendorfer et al.: Effects on Coronary Patients
473
15% in the last 10.2 km. Subject 3 developed severe leg cramps and was forced to walk several km. Subjects 4 and 5 fatigued considerably and could only manage a fast walk alternating with brief periods of jogging. estimated from velocity dropped to 26.4 ml.kgl.min-l while HR remained at 140 bemin-l. No attempt was made to correct for the 3 km uphill portion of this stage since the grade was slight (1.0%) and subjects 3, 4, and 5 walked much of the way. The overall adjusted was 29.8 ml-kg-'*min-' (about 1.92 literamin-') or 72% of Po*max (TABLE3 ) . It should be noted that this method of estimating 3, did not consider downhill running for 4.4 km, nor running with an aiding wind (-4.0 masec-') for about 3 km. Had HR been used to estimate throughout the race, predicted 3 , would have averaged 2.10 literemin-' (79% of Po,max).However, the value of 1.92 literemin-l is believed more accurate because HR tends to rise during prolonged exercise.
voz
vo2
vo2
vo,
Energy Expenditure
The calculated mean energy cost was 2770 kcal (TABLE 3). This value can also be expressed as 1.0 kcal.kg-l.km-l, which is identical to that found by Margaria er aLIO for brief bouts of treadmill running.
TABLE3 OBSERVATIONS ON FIVE CORONARY PATIENTS DURING ROADRUNNING AND A MARATHON RACE(42.2 km) Subject No. 1
2
3
4
5
Mean
3.03 53.2 176
2.33 37.4 175
2.67 44.2 180
2.91 37.3 165
2.35 34.5 174
2.66 41.3 174
Road Running VO,,,.
liter .min-' ml .kg-l-min-' HR,,. b.min-' Marathon Race Finishing Time, min Velocity, m.min-' O2uptake, ml-kg-'.min-' * Osuptake., 1iter.min-' * % of VOZmsr Energy expenditure, kcal Mean heart rate, barnin-' % of HR,.. Peak heart rate, b.min-' Fluid intake, ml Rectal temp., ' C Weight loss, kg
299 205 335 370 285 302 205 148 126 114 147 140 37.6 33.1 23.0 29.8 29.6 25.7 2.19 1.85 1.98 1.97 1.60 1.92 74 68 68 72 72 79 2200 2584 2930 3234 2901 2770 139 161 147 141 133 144 79 92 82 85 78 83 160 164 164 160 168 163 840 1400 1540 850 2140 1350 39.0 38.5 38.6 38.6 38.4 38.6 1.8 2.4 2.2 2.6 1.4 2.1
* Estimated from running velocity
(FIGURE 1).
Annals New York Academy of Sciences
474 Fluid Exchange
Fluid intake during the race averaged 1350 ml and the observed weight loss
was 2.1 kg, or 3.1 % of prerace body weight (TABLE 3). Thus, the total weight loss was 3.45 kg, of which 0.45 kg (13%) represented respiratory losses, and the remaining 3.0 kg was sweat. The calculated rate of sweating was 0.6 kg.hrl (340 ml*m-2-hr1).
1S-TAGE
I
STAGE
z
1%
'Sk
3 g w E
' *-
,!: I
130
,
12
s
5
,
,
10
15
2 4 % qrode I )
-
-
STAGE 1 3
,
,
,
, ,
25
30
35
4 O F
40m , redheadwind x)
I+--
DISTANCE, k m
FIQ- 3. Observations of running velocity, estimated 0%uptake, and heart rate during the marathon race. Rectal Temperature
Postrace T, averaged 38.6" C (TABLE 3) under ambient conditions that can be considered thermally stressful for long distance running. Subjective Responses The major source of discomfort during the race was leg fatigue in the last 10 km. Following the race, subjects 1 and 2 were seemingly well recovered after only 10 minutes. On the other hand,'subjects 3, 4, and 5 complained of
Dressendorfer et af.: Effects on Coronary Patients
475
leg cramps and stiffness. Aside from the leg cramps, there were no symptoms related to heat exhaustion. There were also no symptoms of dypsnea or angina. Treadmill Testing
The results of treadmill tests held two weeks before and immediately after the race are compared in TABLE 4. Cardiorespiratory Responses
Heart rates were not significantly different since the HR obtained in the prerace test was used as a target level for the test after the race. At a mean HR of 139 b-min-l there was a 17% reduction in treadmill speed and a significantly lower 90,by 0.1 1 litermin-l during the postrace test. Predictions of using treadmill speed in the equation derived from measurements of to,during road running were close to observed values in the prerace test but underestimated after the race by 10%. The predicted for the postrace treadmill test was, however, in agreement with findings by Jankowski et al.” Thus, it appears that muscular fatigue from the race resulted in decreased mechanical efficiency for treadmill exercise and an elevated H R for a given V0,. Mean H R values for both tests were similar to mean HR during the race (TABLE3).
vo2
vo2
vo2
Electrocardiogram
Subjects 1 and 3 had normal records for both tests. Subject 2 had >2 mm S-T segment depression with occasional premature ventricular beats during and after the prerace treadmill test. His S-T depression was 1 to 2 mm after the race and also during the postrace test he had fewer premature beats. Subjects 4 and 5 had minimal (0 to 1 mm) S-T depression during the first test but no depression after the race. Systolic Time Intervals
Recovery HR was significantly higher after the race. Comparisons against normalized STI values corrected for HR were therefore required (TABLE 4). Subjects 1, 2, and 5 had normal left ventricular ejection time (LVET) and pre-ejection period (PEP) for both tests. Subjects 3 and 4 had prolonged LVET that were borderline normal for both tests. Biochemical Results
FIGURES 4 through 8 show the results of blood analysis. Hct, Hb, and total protein, which may be used to indicate changes in hemoconcentration,12 were
Annals New York Academy of Sciences
476
not significantly different from resting values either after the prerace treadmill run or after the marathon race (FIGURE4). Compared to treadmill running the 205 to 370 minute marathon for 15 minutes at a similar percent of Go, run had no statistically significant effects on Hct, Hb, total protein, and albumin (FIGURE4), triglycerides, cholesterol, and glucose (FIGURE51, sodium, potassium, magnesium, and phosphorus (FIGURE6) ; alkaline phosphatase and GOT (FIGURE7), and total bilirubin (not shown).
TABLE4 CARDIORESPIRATORY RESPONSESTO TREADMILL RUNNNINC IN FIVETRAINED CORONARY PATIENTS BEFORE AND AFTER A MARATHONRACE (42.2 km)* 15 Days before Race
Weight, kg Treadmill speed, m min-' Heart Rate, b-min-' % of HR,,. 0,uptake liter emin-' mi * kg-.' min-' % of VOlrn.x Expired min vol, liter.min-' (BTPS) COz output, litersmin-' Resp. exchange ratio Rectal temp, C Blood pressure, mmHg Systolic time intervals 5 HR, b. min-' LVET, msec PEP, msec 9
-
15 Minutes
after Race
Pt
65.1 k 8 . 2 142226 14229 81 2 4
64427.6 118217 13927 8023
NS NS NS NS
1.8420.10 28.323.6 70f7
1.73f 0 . 1 6 27.2k4.4 6626
How well do trained heart patients respond to the physiological demands of marathon running? As part of a long-range project investigating the efficacy of longdistance running ( 2 10 km) in the treatment and prevention of coronary artery disease, the present study was undertaken to quantify physiological adjustments of five trained coronary patients to running the 1974 Honolulu Marathon (42.2 km). The study provides supportive and additional data on the above question regarding the physiology and safety of marathon running by myocardial infarct patients.' Reported findings include cardiorespiratory, thermal, biochemical, and metabolic measurements made before, during, and after the marathon run. PATIENTS AND METHODS Subjects
Five moderately to well trained middle-aged men were selected from volunteers in a group of coronary patients who had undergone 6 months of marathon training. On the average, these subjects were quite typical of patients in our cardiac rehabilitation program who show improvement with physical conditioning. The selection was made to provide a range in type and severity of coronary artery disease on the basis of diagnostic tests made one year earlier. A description of subjects is presented in TABLE1. Subject 1 showed electrocardiographic signs of ischemia with chest pains during maximal treadmill stress testing and was presumed to have coronary artery disease. Subjects 2-5 had healed myocardial infarcts (MI), which occurred 1.5 to 4 years before the race. The MISwere diagnosed and quantified with electrocardiographic changes,
* This work was supported in part by a grant from the Honolulu Medical Group Research Foundation. t Present address: Human Performance Laboratory, Department of Physical Education, University of California at Davis, Davis, Calif. 95616. 466
Dressendorfer et al. : Effects on Coronary Patients
467
serum enzyme levels, angiograms, and vectorcardiography. Subject 5 underwent surgical bypass revascularization of three coronary arteries 1 year before the race. TABLE 1 also shows measurements of average skinfold thickness, resting pulse rate, and blood pressure. Percent body fat, predicted from triceps, subscapular, and umbilical skinfolds,2 averaged 18.7 % Subject 4, estimated as 32% fat, was classified obese despite a substantial weight loss during training. Subject 3 was a finisher in the 1973 Honolulu and 1974 Boston marathons. Smoking and alcohol consumption had been discontinued for about 1 year. TABLE 2 shows fasting serum levels for cholesterol, triglycerides, uric acid, glucose, sodium, and potassium as determined 2 weeks before the race. Mean values were within the clinical range of normal. Before exercise reconditioning, subject 5 had serum cholesterol and triglyceride levels of 344 and greater than 1200 mg/dl, respectively. In the month preceding the marathon race, training distance for the group averaged 60 to 75 km-wk-l at a mean velocity of about 150 m-min-l. Subject 1, however, consistently averaged 140 km.wk-1, whereas subjects 4 and 5 were bothered by minor leg injuries that prevented their training mileage from increasing beyond a level of 60 kmewk-l. Longest training runs before the race were 25 to 30 km. During these long runs no subject experienced angina pectoris.
.
Design of Experiment
(vo,)
Measurements of oxygen uptake and heart rate (HR) were made 1 to 3 weeks before the race during road running tests at various velocities to a maximum. The observed relationships between Po, and running velocity and to,and HR for each subject were subsequently used in estimating during the race. Fifteen days before the race, each subject performed a 15-minute treadmill run at 80%-85% of his highest observed HR (HR,,,) while respiratory metabolism and the electrocardiogram (ECG)were obtained. Determinations of systolic time intervals (STI) , measured in the supine position, were made before and approximately 5 minutes postexercise. In addition, rectal temperature (T,) was measured and blood and urine were collected before and 5 to 10 minutes after the treadmill run. Urine samples and body weights were taken within 10 minutes before the race. During the race each subject was accompanied by a cardiac nurse who bicycled alongside. Whenever the subject stopped to consume fluids, the nurse palpated his pulse and recorded time, place, and quantity of fluid consumed. Immediately after completing the race, the subject was escorted to an air-conditioned room located 100 m from the finish line where body weight, T,,, and blood and urine samples were obtained within 10 minutes. The subject then performed a second treadmill test at the target HR level obtained in the first treadmill test. Respiratory metabolism, ECG, and recovery STI were determined as before.
vo,
175
43
47
47
46
3*
4
5
Mean 65.1
62.1
77.9
60.4
62.1
56.9
Weight (kg)
59
68
54
64
60
~~
(>2 mm) during treadmill stress test; presumed coronary artery disease (1 yr) 3 4 cm antedor transmural MI with dyskinetic segment and presumed ventricular aneurism (4 Yr) 4-5 cm inferior transmural MI (2yr) 4-5 cm inferior transmural MI (2 yr) MI (1.5 yr); triple bipass aorto-coronary transplant (1 yr) 4 patients post-MI, 1 patient asymptomatic
S-Tsegment depression
History of Coronary Disease (years before marathon race)
thigh.
t Unweighted average skinfold thickness measured at seven sites: triceps, subscapular, suprailiac, umbilical, chest, axillary, and front
121/79
100/70
130/84
140/84
128/84
108/72
50
-
Sitting Blood Pressure (mmHg)
Sitting Pulse Rate (b m i d )
t Completed two previous marathon races (42.2 km) within preceding year.
15.8
18.7
26.2
8.4
11.7
14.2
Subcutaneous Fat t (mm)
* Measurements made two weeks before marathon race.
171
170
175
168
45
2
169
Height (cm)
48
Age (yr)
1
No.
Subject
TABLE 1 DESCRIPTION OF SUBJECTS*
P3
w
b
s
P
469
Dressendorfer et al. : Effects on Coronary Patients Measurement Techniques
Field testing to determine the energetics of road running was conducted along a flat, approximately 800 m circuit after the subjects had completed training runs of 10 to 15 km. The subject ran 1 m beside a car at self-paced running velocities up to a voluntary maximum. At each velocity, expired gas was collected in a 200-liter meteorological balloon over the second 400 m using portable respiratory equipment designed for this p ~ r p o s e Duplicate .~ gas samples were drawn in glass syringes and measured for 0, and CO, concentrations with a micro-gas analyzer (Scholander, Rutledge, Pa.). Gas volume and temperature were measured after each run in a gasmeter (Type CD4, ParkinsonCowan, Blue Bell, Pa.). Maximal 0, uptake (3,,1,,,,,)was defined as the highest Vo, observed, which typically leveled off at maximum velocities. Exercise HR was estimated by timing 15 carotid pulses in the immediate recovery. TABLE 2 FASTING SERUMLEVELS*
Uric Subject Cholesterol Triglycerides Acid No. (mg/dl) (mg/dl) (mg/dl) 1 2 3 4 5
Mean
215 185 250 305 205 232
90 196 83 100 273 150
8.2 6.7 5. I 5.9 8.8 6.9
Glucose (mg/dl)
Na (meq/l)
(meq/l)
109 120 103 122 105 112
142 146 147 145 143 145
4.1 4.6 4.8 5.0 5.3 4.8
K
'! Blood samples taken 2 weeks before marathon race, 12 to 16 hours after eating,
with the subjects being well rested.
Zero grade was used in both treadmill tests. Expired gas was collected and analyzed as discussed above. Heart rate was determined from the ECG obtained using bipolar chest leads placed in the V, and manubrium positions. STI values before and after exercise were measured according to the method and procedures described in detail by Maher et al:' Body weight was measured on a platform scale accurate to k 5 0 g. Sweat loss during the race was estimated from changes in body weight after correcting for fluid intake and respiratory weight losses.5 Fluid intake, which included water and sundry solutions of sugar and electrolytes, was measured by using containers of known volume. Rectal temperature was measured with a mercuryin-glass thermometer inserted 8 cm. Blood samples were drawn by syringe from an antecubital forearm vein at rest before and then 8 to 10 minutes following the first treadmill test, and also 8 to 10 minutes after the race. Technical difficulties precluded blood sampling before the race. All determinations were made on serum except for
470
Annals New York Academy of Sciences
hematocrit (Hct), hemoglobin (Hb), and lactate, which were made on whole blood. Analysis for total protein, albumin, cholesterol, calcium, inorganic phosphorous, glucose, creatinine, uric acid, total bilirubin, alkaline phosphatase (Enzyme Code 3.1.3.1), lactate dehydrogenase (LDH, E.C. 1.1.1.27), and aspartate minotransferase (GOT, E.C. 2.6.1.1 ) were performed on a sequential multiple automatic analyzer (Type 12/60, Technicon Instruments Corp., Tarrytown, N.Y.). Hct, calculated as mean corpuscular volume times red blood cell count, and Hb were determined with a cell counter (Model S, Coulter, Hialeah, Fla.). Lactate was analyzed by the enzymatic method using a commercially available test kit (Sigma Chemical Co., St. Louis, Mo.). Osmolality was determined by freezing point depression. Triglycerides were measured by a fluorometric procedure.6 Sodium, potassium, and magnesium were determined by atomic absorption. Alphahydroxybutyrate dehydrogenase (a-HBDH, E.C. 1.1.1.27) was determined with a commercial test kit (Boehringer, Indianapolis, Ind.). Creatine phosphokmase (CPK, E.C. 2.7.3.2) was analyzed according to Rosalki.7 AU serum enzyme determinations were done spectrophotometrically at 25°C by measuring either the appearance or disappearance of NADH or NADPH. A full report on the methods and results of urine analysis will be published elsewhere. Marathon Race The subjects were among 19 cardiovascular patients who completed the 1974 Honolulu Marathon, a certified road course measuring 42,195 m. Most of the course was flat, but a hill 38 m in vertical elevation had to be climbed at 8.4 km (average grade of 2.4% for 1400 m) and again at 36.9 km (average grade of 1.0% for 3000 m). Thus, hill-running on two gradual slopes comprised 20% of the race. The course record as of 1975 was 2:17.24 (J. Foster, New Zealand). Ambient conditions at the start (6:30 AM) to when the last subject finished (12:40 PM) ranged as follows: T,,,22" to 28°C; RH, 79% to 58%; wind velocity, 3.6 to 6.7 m-sec-l; cloud cover, about 50%. Runners were resisted by an average 4.0 m-sec-l headwind for 7.5 km and aided by an equally strong tailwind for 3 km. Physicians and nurses were available at 11 first aid and refreshment stations along the course beginning at 5 km. RESULTS Subjects were numbered according to their sequence of finishing the race. 0, Uptake during Road Running
vo,
FIGURE 1 shows curves relating (mlekg-l mmin-l) to running velocity (mamin-1) for each subject. Oxygen uptake was a linear function of velocity before plateauing at an apparent mar, which averaged 2.66 litersmin-l (41.3
v0,
Dressendorfer et al.: Effects on Coronary Patients
47 1
ml*kgl*min-l). Regression analysis of grouped data excluding points after po2began leveling off resulted in the least squares best fit equation: Po?= 0.158 (velocity) 6.0. This relationship had a highly significant correlation coefficient of 0.97. Although resting Vozwas not used in the linear regression analysis, the value of 6.0 ml-kg1.min-1 at the y intercept approximated standing Po, prior to running. Individual curves relating HR to Voa are shown in FIGURE 2. Peak values for HR averaged 176 b.min-l. For subjects 1, 3, and 4 only, ~ O z m n rwas also measured during uphill treadmill running and results were within +3 ml.kg1.rnin-1 of their road running values.
+
55
-
1
I
I
cz
X
-.
40-
E
u
X
g
35-
3 E 0
5
30-
0
25
1
4
3
120
I60 Road
200 Running
240
280
320
Velocity, m.min-'
FIGURE 1 . Relationship between road running velocity and Oa uptake in five coronary patients. Subject numbers are shown in parentheses. Arrows indicate average velocity during the marathon race. Observations during the Marathon Race
Observed and derived data for each subject are presented in TABLE3. Finishing times averaged 299 minutes and ranged from 205 to 370 minutes. Estimation of V ,
Running velocity was determined at 7 to 10 locations on the course and averaged 147 m-min-l. For descriptive purposes, the race was arbitrarily subdivided into the following three stages: start to 16 km, 16 to 32 km, and 32
Annals New York Academy of Sciences
472
3.0
2.5
-
-E C
X 0
0 c
3 2.0 C
V
F
0
1.5 //
I
130
,
I
I40 Heart
150
I
I60
I
I70
, 180
R a t e , barnin-'
FIGURE 2. Relationship between heart rate and the O1 uptake during road running 1. Arrows indicate average heart rate for each subject during the shown in FIGURE marathon race.
voz,
km to finish. FIGURE 3 shows velocity, HR, and % Po2mnx for each stage. Average velocity for each stage was 156, 149, and 129 m-min-', respectively. From the start to 16 km, to,was 30.7 ml.kg'.min-l and H R averaged 150 b-min-l. The hill climb at 8.4 km increased HR to 163 b-min-l, which predicted a of 2.53 liter.min-' (39.2 ml.kg1.min-') or 95% of If we assume the runners maintained their velocity, the predicted is very similar to that observed in treadmill studies.* Uphill running, therefore, increased the average Po, for this stage to 31.4 ml.kg-l.min-l. From 16 to 32 km, was 29.5 ml*kg-'.min-l while H R was 141 barnin-'. During this part of the race, however, the subjects were confronted by a steady 4.0 m.sec-l headwind for 7.5 km, which according to Pugh@should have increased 3, by 0.14 liter-min-' to about 31.6 ml-kg-min-'. Thus, the adjusted average for this stage was 30.4 ml.kgl.min-l. Except for subject 2 who maintained his pace, average velocity decreased
coz
vo2mnx. voz
co2
vo2
Dressendorfer et al.: Effects on Coronary Patients
473
15% in the last 10.2 km. Subject 3 developed severe leg cramps and was forced to walk several km. Subjects 4 and 5 fatigued considerably and could only manage a fast walk alternating with brief periods of jogging. estimated from velocity dropped to 26.4 ml.kgl.min-l while HR remained at 140 bemin-l. No attempt was made to correct for the 3 km uphill portion of this stage since the grade was slight (1.0%) and subjects 3, 4, and 5 walked much of the way. The overall adjusted was 29.8 ml-kg-'*min-' (about 1.92 literamin-') or 72% of Po*max (TABLE3 ) . It should be noted that this method of estimating 3, did not consider downhill running for 4.4 km, nor running with an aiding wind (-4.0 masec-') for about 3 km. Had HR been used to estimate throughout the race, predicted 3 , would have averaged 2.10 literemin-' (79% of Po,max).However, the value of 1.92 literemin-l is believed more accurate because HR tends to rise during prolonged exercise.
voz
vo2
vo2
vo,
Energy Expenditure
The calculated mean energy cost was 2770 kcal (TABLE 3). This value can also be expressed as 1.0 kcal.kg-l.km-l, which is identical to that found by Margaria er aLIO for brief bouts of treadmill running.
TABLE3 OBSERVATIONS ON FIVE CORONARY PATIENTS DURING ROADRUNNING AND A MARATHON RACE(42.2 km) Subject No. 1
2
3
4
5
Mean
3.03 53.2 176
2.33 37.4 175
2.67 44.2 180
2.91 37.3 165
2.35 34.5 174
2.66 41.3 174
Road Running VO,,,.
liter .min-' ml .kg-l-min-' HR,,. b.min-' Marathon Race Finishing Time, min Velocity, m.min-' O2uptake, ml-kg-'.min-' * Osuptake., 1iter.min-' * % of VOZmsr Energy expenditure, kcal Mean heart rate, barnin-' % of HR,.. Peak heart rate, b.min-' Fluid intake, ml Rectal temp., ' C Weight loss, kg
299 205 335 370 285 302 205 148 126 114 147 140 37.6 33.1 23.0 29.8 29.6 25.7 2.19 1.85 1.98 1.97 1.60 1.92 74 68 68 72 72 79 2200 2584 2930 3234 2901 2770 139 161 147 141 133 144 79 92 82 85 78 83 160 164 164 160 168 163 840 1400 1540 850 2140 1350 39.0 38.5 38.6 38.6 38.4 38.6 1.8 2.4 2.2 2.6 1.4 2.1
* Estimated from running velocity
(FIGURE 1).
Annals New York Academy of Sciences
474 Fluid Exchange
Fluid intake during the race averaged 1350 ml and the observed weight loss
was 2.1 kg, or 3.1 % of prerace body weight (TABLE 3). Thus, the total weight loss was 3.45 kg, of which 0.45 kg (13%) represented respiratory losses, and the remaining 3.0 kg was sweat. The calculated rate of sweating was 0.6 kg.hrl (340 ml*m-2-hr1).
1S-TAGE
I
STAGE
z
1%
'Sk
3 g w E
' *-
,!: I
130
,
12
s
5
,
,
10
15
2 4 % qrode I )
-
-
STAGE 1 3
,
,
,
, ,
25
30
35
4 O F
40m , redheadwind x)
I+--
DISTANCE, k m
FIQ- 3. Observations of running velocity, estimated 0%uptake, and heart rate during the marathon race. Rectal Temperature
Postrace T, averaged 38.6" C (TABLE 3) under ambient conditions that can be considered thermally stressful for long distance running. Subjective Responses The major source of discomfort during the race was leg fatigue in the last 10 km. Following the race, subjects 1 and 2 were seemingly well recovered after only 10 minutes. On the other hand,'subjects 3, 4, and 5 complained of
Dressendorfer et af.: Effects on Coronary Patients
475
leg cramps and stiffness. Aside from the leg cramps, there were no symptoms related to heat exhaustion. There were also no symptoms of dypsnea or angina. Treadmill Testing
The results of treadmill tests held two weeks before and immediately after the race are compared in TABLE 4. Cardiorespiratory Responses
Heart rates were not significantly different since the HR obtained in the prerace test was used as a target level for the test after the race. At a mean HR of 139 b-min-l there was a 17% reduction in treadmill speed and a significantly lower 90,by 0.1 1 litermin-l during the postrace test. Predictions of using treadmill speed in the equation derived from measurements of to,during road running were close to observed values in the prerace test but underestimated after the race by 10%. The predicted for the postrace treadmill test was, however, in agreement with findings by Jankowski et al.” Thus, it appears that muscular fatigue from the race resulted in decreased mechanical efficiency for treadmill exercise and an elevated H R for a given V0,. Mean H R values for both tests were similar to mean HR during the race (TABLE3).
vo2
vo2
vo2
Electrocardiogram
Subjects 1 and 3 had normal records for both tests. Subject 2 had >2 mm S-T segment depression with occasional premature ventricular beats during and after the prerace treadmill test. His S-T depression was 1 to 2 mm after the race and also during the postrace test he had fewer premature beats. Subjects 4 and 5 had minimal (0 to 1 mm) S-T depression during the first test but no depression after the race. Systolic Time Intervals
Recovery HR was significantly higher after the race. Comparisons against normalized STI values corrected for HR were therefore required (TABLE 4). Subjects 1, 2, and 5 had normal left ventricular ejection time (LVET) and pre-ejection period (PEP) for both tests. Subjects 3 and 4 had prolonged LVET that were borderline normal for both tests. Biochemical Results
FIGURES 4 through 8 show the results of blood analysis. Hct, Hb, and total protein, which may be used to indicate changes in hemoconcentration,12 were
Annals New York Academy of Sciences
476
not significantly different from resting values either after the prerace treadmill run or after the marathon race (FIGURE4). Compared to treadmill running the 205 to 370 minute marathon for 15 minutes at a similar percent of Go, run had no statistically significant effects on Hct, Hb, total protein, and albumin (FIGURE4), triglycerides, cholesterol, and glucose (FIGURE51, sodium, potassium, magnesium, and phosphorus (FIGURE6) ; alkaline phosphatase and GOT (FIGURE7), and total bilirubin (not shown).
TABLE4 CARDIORESPIRATORY RESPONSESTO TREADMILL RUNNNINC IN FIVETRAINED CORONARY PATIENTS BEFORE AND AFTER A MARATHONRACE (42.2 km)* 15 Days before Race
Weight, kg Treadmill speed, m min-' Heart Rate, b-min-' % of HR,,. 0,uptake liter emin-' mi * kg-.' min-' % of VOlrn.x Expired min vol, liter.min-' (BTPS) COz output, litersmin-' Resp. exchange ratio Rectal temp, C Blood pressure, mmHg Systolic time intervals 5 HR, b. min-' LVET, msec PEP, msec 9
-
15 Minutes
after Race
Pt
65.1 k 8 . 2 142226 14229 81 2 4
64427.6 118217 13927 8023
NS NS NS NS
1.8420.10 28.323.6 70f7
1.73f 0 . 1 6 27.2k4.4 6626
