PARTVI. CARDIACREHABILITATION
CHARACTERISTICS OF POSTCORONARY MARATHON RUNNERS Terence Kavanagh, Roy J. Shephard, and Johanna Kennedy Toronto Rehabilitation Centre Toronto, M4C l R 7 , Ontario Canada Department of Preventive Medicine and Biostatistics University of Toronto Toronto, Ontario Canada
Previous papers from this laboratory discussed the participation of small groups of our “postcoronary” patients in marathon running events.l-O The main focus of these reports was upon the immediate problems of nutrition, fluid and mineral balance, and temperature homeostasis. Further analysis of the data seems warranted to determine to what extent we are dealing with an atypical subsample of the general population of patients with ischemic heart disease. Accordingly, we have now traced the course of training in 13 postcoronary patients who have each completed from one to eight marathon events, comparing results with those for 610 unselected cases of ischemic heart disease attending an exercise-based rehabilitation program. METHODS Subjects. The marathoners were all patients who had sustained a myocardial infarction; the larger unselected sample of 610 patients were also mainly uncomplicated infarcts, although 47 cases of angina and 24 by-pass operations were also included in the sample. Laboratory data were collected on enrollment at the Toronto Rehabilitation Centre, and at intervals of 3-6 months thereafter. In the larger sample, the training results were obtained after an average of 22 months conditioning. Personality Measurements. The Minnesota Multiphasic Personality Inventory was completed under the supervision of a psychologist 16-18 months postinfarction, with repetition of the test 2 years later. Body Composition. Height, weight, and skinfold thickness (triceps, subscapular and suprailiac folds) were measured by standard anthropometric technique^.^ Body fat and thus lean body mass were predicted using the equations of Durnin & Rahaman.” Exercise Tests. Maximal treadmill stress tests were carried out on all members of the marathon group from 1972. However, for comparative purposes they were also assessed at the same times as the general group by the following submaximal test. Exercise was performed on a Fleisch ergostat at a constant pedal speed of 60 rpm. A three-stage progressive test format was used, with three minutes of exercise at each stage, loadings being adjusted to bring subjects to a final 75% of aerobic power. The heart rate and electrocardiogram were monitored throughout, using standard chest leads (CM,). Expired gas was
455
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Annals New York Academy of Sciences
collected by a standard open-circuit technique during the final minute at each work load, with analysis of oxygen (paramagnetic method) and carbon dioxide (infrared analysis) for determination of oxygen consumption. The maximum oxygen intake was predicted from the oxygen scale of the Astrand nomogram;9 previous work has shown a good concordance between such estimates and direct measurements of aerobic power in our postcoronary patients.1° Systemic blood pressures were measured by a standard clinical cuff, with the subjects sitting at rest on the bicycle ergometer; readings were obtained prior to exercise and during the final 15 seconds at each work load; the exercise figure to be discussed is that obtained at the 75% loading. ST segmental sagging was determined using an analog computer to average 16 successive ECG complexes; the results to be discussed are again those obtained at the 75 % loading. RESULTS Clinical Status
In most respects, the marathoners were typical of patients attending the Toronto Rehabilitation Centre. The average period of hospital stay following infarction was 28 days. Complications were few, but one patient was found to have extensive 3 vessel disease that was unsuitable for an aortocoronary bypass and so a Vineberg procedure was carried out. Three of the 13 men had suffered two distinct infarctions, five had been troubled by dysrythmia at various times, and five had some degree of hypertension (diastolic pressure greater than 90 mmHg in two cases, and greater than 100 mmHg in three cases.) Almost all types of infarct were represented, five being posterior, five inferior, and six anterior in site; ten of the 16 episodes were transmural infarctions. We were unable to obtain quantitative estimates on infarct size; nevertheless, all episodes were accompanied by substantial elevations of SGOT levels, the average recorded peak being 172 units (TABLE 1). All of the marathoners had been heavy smokers prior to their attack. None of the group had any experience of distance running prior to their infarction. Personality
The personality, as assessed by the MMPI, showed somewhat lower depression (D) scores for the marathoners than in some of the postcoronary patients,'l average normalized scores amounting to 58 and 63 units, respectively. Nevertheless, the marathoners were significantly depressed relative to the general population. Compared with the 44 depressed postcoronary patients discussed elsewhere in this issue,15 the marathoners had low scores for hysteria (Hy) , hypochondriasis (Hs) , psychasthenia (Pt) , and social introversion (Si) . On the other hand, neither hypomania (Ma) nor masculinity (Mf) was very different from scores attained by the 44 depressed patients. Training did not produce large changes in personality scores for the inarathoners (TABLE 2). Average readings for hysteria, hypochondriasis, and social introversion all showed an insignificant decline, while psychopathic deviation (Pd), schizophrenia (Sc), and hypomania showed small and in-
M
L
K
I J
H
G
D E F
C
B
A
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
1st Non-TM posterior 2nd TM posterior Non-TM anterior T M anterior-septa1 Non-TM posterior-lateral TM inferior 1st TM posterior 2nd Non-TM inferior TM inferior 1st Non-TM anterior 2nd T M anterior non-TM anterior TM anterior-lateral TM inferior TM posterior-lateral TM inferior
* VP,Vineberg procedure.
Enzymes Elevated
Electrocardiographic Findings Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
Characteristic Chest Pain at Infarction
Yes No No No Yes No No Yes No Yes No No No
Yes
No Yes
History of Angina
v p :* No No No No No No No No No No No No
No
No No
Pump Failure
OF MARATHON PATIENTS CLINICALCHARACTERISTICS
TABLE 1
No
No Yes No No No No No Yes No No No Yes Yes Yes No
Dysrhythmia
Complications
No No 150/110 160/90 160/90 No No No No No No 160/105 150/110 No No No
Hypertension
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Kavanagh et af.: Postcoronary Runners
459
significant increments. One subject who completed a full marathon in 1973 but was reduced to a half marathon in 1976 (H.B.) showed changes in the opposite direction to the remainder of the group for most of these variables. Body Composition
The body build of the marathoners was unremarkable and indeed in some instances unfavorable to distance running (TABLE 3). Stature was above the average for our postcoronary group, and the weight was also at least average, one of the marathoners weighing an initial 91.2 kg. However, initial skinfold readings (average 13.5 2 4.1 mm) were lower than in the general sample of postcoronary patients (15.6 2 5.0 mm). The percentage of body fat averaged 19.6% in the marathoners; this was similar to data for other postcoronary patients, and more typical.of a sedentary young man than a distance runner. TABLE3 A COMPARISON OF BODY COMPOSITION BETWEEN 13 MARATHON PARTICIPANTS AND 610 UNSELECTED MEN AITENDINGA POSTCORONARY REHABILITATION
* PROGRAM Marathon
Mean Age (yr) Height (cm) Weight (kg)
Excess weight (kg) Skinfold (mm) (average for 3 folds) Percent fat Lean body mass (kg ) Lean body mass per cm
45.5 176.0 75.1 4.8
SD
25.8 26.8 f 10.3 26.9
f4.1 13.4 19.2 f3.4 60.5 27.2 0.343 k0.030
Total Sample
Range 35-57 167.6-189.2 61.1-91.2 -4.5-+20.0 7.3-16.9 12.5-24.0 50.3-71.1 0.299-0.397
Mean 48.6 173.3 75.9 7.6 ~~
SD
~~
15.6 19.7 59.9 0.345
+7.8 2 6.9
28.4 27.2 25.0
23.4 k6.1
f0.028
* Data obtained on entry to the rehabilitation program. Lean mass per cm of standing height was also close to the anticipated figure for a sedentary young man. Training did not lead to significant changes of body composition in either the marathoners or the general postcoronary group (TABLE4). Exercise Tests The initial aerobic power of the marathoners (28.0 2 4.7 ml/kg.min) was slightly greater than in the unselected cases of ischemic heart disease (25.1 ml/kg*.min). Training of the marathon group led to a progressive increase of VO,mar to a peak of 43.5 2 10.4 ml/kg*min (155% of initial value, 125% of age-matched Toronto normal l*) over an average of 2 years of conditioning. Some of the subjects who were frequent marathon participants showed even larger changes (FIGURE 11, four of the group progressing from
Annals New York Academy of Sciences
460
TABLE4 CHANGES IN BODYCOMPOSITION WITH TRAINING. A COMPARISON BETWEEN 13 MARATHON RUNNERSAND 610 MEN ATTENDINGPOST-CORONARY PROGRAM. CHANGE FROM INITIAL TO MOST RECENTDATA Marathon
Body weight (kg) Excess weight (kg) Skinfold thickness (mm) Percentage fat Lean body mass (kg ) Lean body mass per cm
h
Total Sample
Mean
S.D.
Mean
+0.52 +0.58 +0.2 +0.16 +0.3 -0.002
24.8 k5.0 22.4 k3.4 k5.9 20.20
+0.19 +0.15 -0.20 -0.29 +0.3 +0.002
S.D. 23.73 k4.18 k4.62 k3.06 22.9 k0.059
-v
60
5.9
sa
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!
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C A
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okt 60
Di.2 69
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lbk
71
71
Data
of
JUM
71
Wr 73
DbC 73
DiC
S C
71
75
Or
76
masurnwit
FIGURE 1. Development of maximum oxygen intake in 13 postcoronary patients. Marathon participation indicated by 0.
Kavanagh et al. : Postcoronary Runners
46 1
an initial average of 26.6 ml/kg.min to 56.0 ml/kg.min over 2 to 4 years; two of the four realized almost a half of their gains in the first 6 months of training, but one took a year to attain 50% of his final gain, and the fourth runner (with a final score of 54.4 ml/kg*min) showed almost no improvement until the fourth year of training. Two of the 13 who ceased vigorous conditioning showed substantial losses of aerobic power (8-10 ml/kg.min) over the following year of observation. Hernodynamic Variables
When first seen, the marathoners had a larger resting systolic pressure and a larger pulse pressure than the general sample (TABLE5 ) . With training, the large pulse pressure remained, but there were significant diminutions of TABLE5 HEMODYNAMIC RESPONSES TO EFFORT.A COMPARISON BETWEEN 13 MARATHON PARTICIPANTS AND 610 MEN ATTENDINGTHE POSTCORONARY PROGRAM * Marathon Mean
Total Sample
SD
Range
Mean
SD
Resf blood presstire ( r r t ~ r i H g ) Systolic 138.5 Diastolic 87.5 Exercise blood pressrirr ( I I I I I I H ~ ) Systolic 174.6 Diastolic 90. I
k 13.3 &10.5
120- I60 70- I00
128.6 87.7
216.8 29.0
k22.2 2 12.5
140-210 70-125
167.9 96.4
225.2 f14.4
ST segr~iei~tnl depression Voltage, at 75% load (heart rate 133.928.8)1 -0.1 I6
&0.15
-0.10
20.13
-0.47-+0.03
* Data obtained on entry to the program. i- The nctunl heart rate attained was closer to 70% load. resting systolic and diastolic pressures (TABLE 6). In contrast, conditioning of the general postcoronary group led to a widening of the resting pulse pressure, with a small but significant increase of systolic pressure, and a small but significant decrement of diastolic pressure. During initial exercise at the 75% loading, the marathon runners again developed a higher systolic pressure and a wider pulse pressure than the general postcoronary population (TABLE 4). With training, both groups improved the systolic pressure that they could sustain at the 75% loading (TABLE 5). The extent of the initial ST segmental sagging was rather comparable in the two groups (Table 4). In six of the 13 marathoners, the initial response to the 75% loading was an ST sagging of more than 0.1 mV. With training, both groups tended towards less negative ST segmental voltages, although there was a suggestion of a somewhat greater improvement in the marathon participants. At the final testing, only two of this group had an ST depression
Annals New York Academy of Sciences
462
of more than 0.1 mV, and in one of these two (J.R.) there had nevertheless been a very large improvement, from -0.47 to -0.12 mV. Part of the explanation in this patient was that he had been a heavy smoker. With marathon participation, he was persuaded to stop smoking; however, he later resumed the habit, to die during his sleep and two years after his last marathon; postmortem did not reveal any evidence of recent coronary occlusion or myocardial infarction and the cause of death was termed “electrical failure.”
TABLE6 HEMODYNAMIC RESPONSE WITH TRAINING. COMPARISON BETWEEN 13 MARATHONPARTICIPANTS AND 610 MEN ATTENDING THE POSTCORONARY PROGRAM. CHANGE FROM INITIAL TO MOST RECENTDATA
CHANGES IN
Marathon Mean
SD
Total Sample Mean
SD ~~
Resting blood pressure (mmHg)
Systolic Diastolic
-8.9 -9.1
214.9 212.6
+3.9 -1.0
220.8 29.2
+13.4 -2.5
221.3 214.0
+14.8 +l.5
224.9 214.2
+0.08
20.17
+0.03
f0.16
Exercise blood pressure (mmHg)
Systolic Diastolic ST segmental depression (mmHg) Voltage, at 75% load (heart rate 132.8+9.8)*
* The actual heart rate attained was closer to 70%
load.
DISCUSSION Specificity of Sample
In terms of their clinical history and previous experience of running, there is little evidence that the marathon team of the Toronto Rehabilitation Centre differs from our general postcoronary population. However, the marathon runners show less evidence of depression and development of the neurotic triad (hysteria, hypochondriasis, and psychasthenia) than is the case for our general sample. Since changes of personality scores in response to marathon preparation and participation were quite limited, we must conclude that relative to the average infarct victim the marathoners had either a less drastic psychological reaction to the acute episode or a more favorable response to early rehabilitation. None of the distance competitors had a D score higher than 23 ( a STEN value of 65 units). If this is indeed the maximum depression compatible with successful preparation for a
Kavanagh et al. : Postcoronary Runners
463
marathon contest, we would conclude that about a half of the patients with myocardial infarction could not undertake such activity. The physiological data supports the idea that the marathoners were in some respects a selected segment of our postcoronary population. The initial estimated percentage of body fat and lean mass were much as in the general sample, but the marathoners had some advantage with respect to pulse pressure, maximum tolerated systolic pressure, and aerobic power. The poorest scores found in the marathon team were an initial body fat of 24%, a lean body mass of 0.299 kg/cm, and an aerobic power of 21.7 ml/kg.min. On each of these criteria, a proportion of our general sample would have been eliminated.
Gains from Marathon Running
Granted that the marathon sample had some initial advantages of mood and physiological status relative to the general postcoronary population, it is still plain that the long distance runners made enormous physiological gains over their period of training. The most striking change was in aerobic power, the improvement in this variable averaging 5 5 % , compared with a gain of only 20% in the general postcoronary population. The infarct victim does not die of a low maximum oxygen intake as such. However, if he can improve his physical condition, then the heart rate and thus the cardiac workload for a given task is reduced. This in turn lessens the occurrence of myocardial ischemia and thus the risk of sudden death from cardiac arrest or ventricular fibrillation. The data also suggests that in marathoners conditioning lessens ST segmental sagging during exercise at 75% loadings, despite an associated increase of systolic blood pressure and an unchanged heart rate. However, this is not categoric proof that exercise has improved the myocardial blood supply through the development of collateral blood channels-other possibilities include an improvement of coronary flow secondary to the cessation of smoking, and a reduction in cardiac workload through myocardial hypertrophy or an alteration of ventricular dimensions. The favorable influence of distance running upon other “risk factors” is well established.13 The decision to engage in distance running can be a significant factor in a successful smoking withdrawal program. It is debatable whether there is much advantage in correcting abnormal blood lipids after a heart attack has occurred; however, if a patient is helped to give up smoking, this can have a major impact on the likelihood that his infarct will recur. There is no doubt that participation in the long distance contests gave these men a tremendous psychological boost. However, this is not reflected in large differences of personality scores between the marathoners and other participants in our program. This is partly because it is easier to reduce the D score in a grossly depressed patient than to change the same variable in a person whose score is only a little above the population average. Another important consideration is that the runners have seen their marathon participation as a triumph for the Centre’s program as well as for themselves; because of their unselfish attitudes, the happy experience has been shared with other more disabled patients, to the point where all have enjoyed a vicarious elevation of mood.
464
Annals New York Academy of Sciences Dangers of Marathon Participation
Since it is well established that unusual, unaccustomed, and prolonged activity can increase the immediate risks of a heart attack,“ it is most important that intending marathon participants prepare themselves thoroughly, undertaking systematic, gradual, medically supervised, and progressive long slow distance training for a number of years before considering formal competition. Each time that a substantial training distance is to be covered, a brief check must be made for warning signs such as increasing angina or unusual dysrhythmia. In our program, a complete physical examination, including a 12-lead electrocardiogram and maximal treadmill stress test is mandatory before and after a formal marathon. During the run itself, the runners must keep to a predetermined pace that has been ascertained to be within safe limits. Individual participants must be advised to compete only against themselves, stopping if there are any unusual symptoms or sensations. To date, 22 of our patients have participated in marathon events in Boston, Hawaii, and Toronto, some with times as good as 190 minutes for the 26% mile course. Happily, over 50 races have been completed without complications, either immediate or late. However, this record will be maintained only by scrupulous attention to the precautions outlined above. The one occasional disadvantage encountered by our distance runners is domestic. A wife put it in these terms: “I married a man who would spend each night in front of the television with a six-pack of beer. Now I find myself living with a running enthusiast, and I’m not sure I like it.” This woman is perhaps the exception. The majority of the wives are proud of the new achievements of their husbands. Nevertheless, the case cited does stress the importance of involving other members of the family in any program of treatment that has major social implications. Compliance with long periods of prescribed exercise is much more likely if this can be pursued as a family.
SUMMARY The characteristics of 13 postcoronary patients who have each completed one to eight marathon events were compared with data obtained on a larger sample of 610 infarct victims attending the Toronto Rehabilitation Centre. In clinical terms, the marathon group was composed of typical postcoronary patients, but personality assessments by the Minnesota Multiphasic Personality Inventory showed less depression than in many of our general sample (average normalized D scores 58 and 63, respectively). None of the marathoners had previous experience of running before their infarction, and body build was not particularly advantageous for distance events [stature ( 176.0 f 6.8 cm) was above average and body weight (75.1 10.3 kg) was average although skinfolds (13.5 & 4.1 mm) were lower than the 15.6 -t 5.0 mm found in the larger sample]. The initial aerobic power (28.0 f 4.7 ml/kg.min) of the marathoners was marginally higher than that of th? larger sample (25.1 ml/kg.min). Training led to a progressive increase of VOIlllnS, so that after 2 years the marathoners attained an average of 43.5 ml/kg.min, a 55% increase over their initial value and a 25% increase over the age-matched sedentary Toronto normal. In con-
Kavanagh et af.: Postcoronary Runners trast, the main sample of pstcoronary patients increased their
465
1,
by only
20% with training. Both at rest and during exercise at 75% of aerobic power, the initial systolic blood pressure and pulse pressure were some 1 0 mmHg larger in the marathoners than in the general sample. Training induced a 9 m m H g fall of resting pressure in the marathoners, but both the marathoners and the larger sample showed an increase of the exercise systolic pressure. ST segmental sagging was reduced in both groups over the training period, although the change in the marathoners (0.08 0.17 m V ) was somewhat larger than in the main sample (0.03 & 0.16 m V ) . Marathon participation did not induce any large changes in personality scores.
*
REFERENCES
R. J. SHEPHARD & V. PANDIT.1974. Marathon running after myocardial infarction. J. Amer. Med. Assoc. 229(12): 1602-1605. SHEPHARD, R. J. & T. KAVANAGH. 1975. Biochemical changes with marathon running-Observations on post-coronary patients. In Metabolic Adaptations to Prolonged Physical Activity. H. Howald & J. Poortmans, Eds. Birkhauser Verlag. Basel, Switzerland. KAVANAGH, T. & R. J. SHEPHARD. 1975. Maintenance of hydration in post-coronary marathon runners. Brit. J. Sports Med. 9: 130-135. KAVANAGH, T. & R. J. SHEPHARD. Hydration of middle-aged marathon runners. Brit. J. Sports Med. In press. 1976. Fluid and mineral balance on postSHEPHARD, R. J. & T. KAVANAGH. coronary distance runners. Studies on the 1975 Boston Marathon. Proceedings, International Conference on Nutrition, Dietetics and Sport, Bordighera. SHEPHARD, R. J., T. KAVANAGH, S. CONWAY, M. THOMSON & G. H. ANDERSON. 1975. Nutritional demands of sub-maximum work: marathon and TransCanadian events. In Proceedings of International Symposium on Athletic Nutrition, Warsaw. WEINER,J. S. & J. A. LOURIE.1975. Human Biology: A Guide to Field Methods. Blackwell Scientific Publishers. Oxford, England. 1967. The assessment of the amount J. V. G. A. & M. M. RAHAMAN. DURNIN, of fat in the human body from measurements of skinfold thickness. Brit. J. Nutrit. 21: 681-689. ASTRAND, I. 1960. Aerobic work capacity in men and women with special reference to age. Acta Physiol. Scand. 49 (Suppl. 169): 1-92. KAVANAGH, T. & R. J. SHEPHARD.1976. Maximum exercise tests on postcoronary patients. J. Appl. Physiol. 4 0 611-618. KAVANAGH, T., R. J. SHEPHARD & J. A. TUCK.1975. Depression after myocardial infarction. Canad. Med. Assoc. J. 113: 23-27. SHEPHARD, R. J. 1977. Endurance Fitness. 2nd edit. University of Toronto Press. Toronto, Canada. & G. W. WRIGHT. 1976. Smoking reduction in adults MORGAN, P., M. GILDINER who take up exercise: A survey of a running club for adults. Canad. Assoc. Health. Phys. Ed. Recreat. J. 42: 39-43. SHEPHARD, R. J. 1974. Sudden death-A significant hazard of exercise? Brit. J. Sports Med. 8: 101-110. KAVANAGH, T., R. J. SHEPHARD & J. A. TUCK.1977. The effects of long distance running program on depression and psychological profile. Ann. N.Y. Acad. Sci. This volume.
T., 1. KAVANAGH, 2.
3.
4. 5. 6.
7. 8. 9. 10. 11. 12. 13. 14.
15.
CHARACTERISTICS OF POSTCORONARY MARATHON RUNNERS Terence Kavanagh, Roy J. Shephard, and Johanna Kennedy Toronto Rehabilitation Centre Toronto, M4C l R 7 , Ontario Canada Department of Preventive Medicine and Biostatistics University of Toronto Toronto, Ontario Canada
Previous papers from this laboratory discussed the participation of small groups of our “postcoronary” patients in marathon running events.l-O The main focus of these reports was upon the immediate problems of nutrition, fluid and mineral balance, and temperature homeostasis. Further analysis of the data seems warranted to determine to what extent we are dealing with an atypical subsample of the general population of patients with ischemic heart disease. Accordingly, we have now traced the course of training in 13 postcoronary patients who have each completed from one to eight marathon events, comparing results with those for 610 unselected cases of ischemic heart disease attending an exercise-based rehabilitation program. METHODS Subjects. The marathoners were all patients who had sustained a myocardial infarction; the larger unselected sample of 610 patients were also mainly uncomplicated infarcts, although 47 cases of angina and 24 by-pass operations were also included in the sample. Laboratory data were collected on enrollment at the Toronto Rehabilitation Centre, and at intervals of 3-6 months thereafter. In the larger sample, the training results were obtained after an average of 22 months conditioning. Personality Measurements. The Minnesota Multiphasic Personality Inventory was completed under the supervision of a psychologist 16-18 months postinfarction, with repetition of the test 2 years later. Body Composition. Height, weight, and skinfold thickness (triceps, subscapular and suprailiac folds) were measured by standard anthropometric technique^.^ Body fat and thus lean body mass were predicted using the equations of Durnin & Rahaman.” Exercise Tests. Maximal treadmill stress tests were carried out on all members of the marathon group from 1972. However, for comparative purposes they were also assessed at the same times as the general group by the following submaximal test. Exercise was performed on a Fleisch ergostat at a constant pedal speed of 60 rpm. A three-stage progressive test format was used, with three minutes of exercise at each stage, loadings being adjusted to bring subjects to a final 75% of aerobic power. The heart rate and electrocardiogram were monitored throughout, using standard chest leads (CM,). Expired gas was
455
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Annals New York Academy of Sciences
collected by a standard open-circuit technique during the final minute at each work load, with analysis of oxygen (paramagnetic method) and carbon dioxide (infrared analysis) for determination of oxygen consumption. The maximum oxygen intake was predicted from the oxygen scale of the Astrand nomogram;9 previous work has shown a good concordance between such estimates and direct measurements of aerobic power in our postcoronary patients.1° Systemic blood pressures were measured by a standard clinical cuff, with the subjects sitting at rest on the bicycle ergometer; readings were obtained prior to exercise and during the final 15 seconds at each work load; the exercise figure to be discussed is that obtained at the 75% loading. ST segmental sagging was determined using an analog computer to average 16 successive ECG complexes; the results to be discussed are again those obtained at the 75 % loading. RESULTS Clinical Status
In most respects, the marathoners were typical of patients attending the Toronto Rehabilitation Centre. The average period of hospital stay following infarction was 28 days. Complications were few, but one patient was found to have extensive 3 vessel disease that was unsuitable for an aortocoronary bypass and so a Vineberg procedure was carried out. Three of the 13 men had suffered two distinct infarctions, five had been troubled by dysrythmia at various times, and five had some degree of hypertension (diastolic pressure greater than 90 mmHg in two cases, and greater than 100 mmHg in three cases.) Almost all types of infarct were represented, five being posterior, five inferior, and six anterior in site; ten of the 16 episodes were transmural infarctions. We were unable to obtain quantitative estimates on infarct size; nevertheless, all episodes were accompanied by substantial elevations of SGOT levels, the average recorded peak being 172 units (TABLE 1). All of the marathoners had been heavy smokers prior to their attack. None of the group had any experience of distance running prior to their infarction. Personality
The personality, as assessed by the MMPI, showed somewhat lower depression (D) scores for the marathoners than in some of the postcoronary patients,'l average normalized scores amounting to 58 and 63 units, respectively. Nevertheless, the marathoners were significantly depressed relative to the general population. Compared with the 44 depressed postcoronary patients discussed elsewhere in this issue,15 the marathoners had low scores for hysteria (Hy) , hypochondriasis (Hs) , psychasthenia (Pt) , and social introversion (Si) . On the other hand, neither hypomania (Ma) nor masculinity (Mf) was very different from scores attained by the 44 depressed patients. Training did not produce large changes in personality scores for the inarathoners (TABLE 2). Average readings for hysteria, hypochondriasis, and social introversion all showed an insignificant decline, while psychopathic deviation (Pd), schizophrenia (Sc), and hypomania showed small and in-
M
L
K
I J
H
G
D E F
C
B
A
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
1st Non-TM posterior 2nd TM posterior Non-TM anterior T M anterior-septa1 Non-TM posterior-lateral TM inferior 1st TM posterior 2nd Non-TM inferior TM inferior 1st Non-TM anterior 2nd T M anterior non-TM anterior TM anterior-lateral TM inferior TM posterior-lateral TM inferior
* VP,Vineberg procedure.
Enzymes Elevated
Electrocardiographic Findings Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
Characteristic Chest Pain at Infarction
Yes No No No Yes No No Yes No Yes No No No
Yes
No Yes
History of Angina
v p :* No No No No No No No No No No No No
No
No No
Pump Failure
OF MARATHON PATIENTS CLINICALCHARACTERISTICS
TABLE 1
No
No Yes No No No No No Yes No No No Yes Yes Yes No
Dysrhythmia
Complications
No No 150/110 160/90 160/90 No No No No No No 160/105 150/110 No No No
Hypertension
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Kavanagh et af.: Postcoronary Runners
459
significant increments. One subject who completed a full marathon in 1973 but was reduced to a half marathon in 1976 (H.B.) showed changes in the opposite direction to the remainder of the group for most of these variables. Body Composition
The body build of the marathoners was unremarkable and indeed in some instances unfavorable to distance running (TABLE 3). Stature was above the average for our postcoronary group, and the weight was also at least average, one of the marathoners weighing an initial 91.2 kg. However, initial skinfold readings (average 13.5 2 4.1 mm) were lower than in the general sample of postcoronary patients (15.6 2 5.0 mm). The percentage of body fat averaged 19.6% in the marathoners; this was similar to data for other postcoronary patients, and more typical.of a sedentary young man than a distance runner. TABLE3 A COMPARISON OF BODY COMPOSITION BETWEEN 13 MARATHON PARTICIPANTS AND 610 UNSELECTED MEN AITENDINGA POSTCORONARY REHABILITATION
* PROGRAM Marathon
Mean Age (yr) Height (cm) Weight (kg)
Excess weight (kg) Skinfold (mm) (average for 3 folds) Percent fat Lean body mass (kg ) Lean body mass per cm
45.5 176.0 75.1 4.8
SD
25.8 26.8 f 10.3 26.9
f4.1 13.4 19.2 f3.4 60.5 27.2 0.343 k0.030
Total Sample
Range 35-57 167.6-189.2 61.1-91.2 -4.5-+20.0 7.3-16.9 12.5-24.0 50.3-71.1 0.299-0.397
Mean 48.6 173.3 75.9 7.6 ~~
SD
~~
15.6 19.7 59.9 0.345
+7.8 2 6.9
28.4 27.2 25.0
23.4 k6.1
f0.028
* Data obtained on entry to the rehabilitation program. Lean mass per cm of standing height was also close to the anticipated figure for a sedentary young man. Training did not lead to significant changes of body composition in either the marathoners or the general postcoronary group (TABLE4). Exercise Tests The initial aerobic power of the marathoners (28.0 2 4.7 ml/kg.min) was slightly greater than in the unselected cases of ischemic heart disease (25.1 ml/kg*.min). Training of the marathon group led to a progressive increase of VO,mar to a peak of 43.5 2 10.4 ml/kg*min (155% of initial value, 125% of age-matched Toronto normal l*) over an average of 2 years of conditioning. Some of the subjects who were frequent marathon participants showed even larger changes (FIGURE 11, four of the group progressing from
Annals New York Academy of Sciences
460
TABLE4 CHANGES IN BODYCOMPOSITION WITH TRAINING. A COMPARISON BETWEEN 13 MARATHON RUNNERSAND 610 MEN ATTENDINGPOST-CORONARY PROGRAM. CHANGE FROM INITIAL TO MOST RECENTDATA Marathon
Body weight (kg) Excess weight (kg) Skinfold thickness (mm) Percentage fat Lean body mass (kg ) Lean body mass per cm
h
Total Sample
Mean
S.D.
Mean
+0.52 +0.58 +0.2 +0.16 +0.3 -0.002
24.8 k5.0 22.4 k3.4 k5.9 20.20
+0.19 +0.15 -0.20 -0.29 +0.3 +0.002
S.D. 23.73 k4.18 k4.62 k3.06 22.9 k0.059
-v
60
5.9
sa
.E
!
u
1
C A
n 20
okt 60
Di.2 69
Jin
lbk
71
71
Data
of
JUM
71
Wr 73
DbC 73
DiC
S C
71
75
Or
76
masurnwit
FIGURE 1. Development of maximum oxygen intake in 13 postcoronary patients. Marathon participation indicated by 0.
Kavanagh et al. : Postcoronary Runners
46 1
an initial average of 26.6 ml/kg.min to 56.0 ml/kg.min over 2 to 4 years; two of the four realized almost a half of their gains in the first 6 months of training, but one took a year to attain 50% of his final gain, and the fourth runner (with a final score of 54.4 ml/kg*min) showed almost no improvement until the fourth year of training. Two of the 13 who ceased vigorous conditioning showed substantial losses of aerobic power (8-10 ml/kg.min) over the following year of observation. Hernodynamic Variables
When first seen, the marathoners had a larger resting systolic pressure and a larger pulse pressure than the general sample (TABLE5 ) . With training, the large pulse pressure remained, but there were significant diminutions of TABLE5 HEMODYNAMIC RESPONSES TO EFFORT.A COMPARISON BETWEEN 13 MARATHON PARTICIPANTS AND 610 MEN ATTENDINGTHE POSTCORONARY PROGRAM * Marathon Mean
Total Sample
SD
Range
Mean
SD
Resf blood presstire ( r r t ~ r i H g ) Systolic 138.5 Diastolic 87.5 Exercise blood pressrirr ( I I I I I I H ~ ) Systolic 174.6 Diastolic 90. I
k 13.3 &10.5
120- I60 70- I00
128.6 87.7
216.8 29.0
k22.2 2 12.5
140-210 70-125
167.9 96.4
225.2 f14.4
ST segr~iei~tnl depression Voltage, at 75% load (heart rate 133.928.8)1 -0.1 I6
&0.15
-0.10
20.13
-0.47-+0.03
* Data obtained on entry to the program. i- The nctunl heart rate attained was closer to 70% load. resting systolic and diastolic pressures (TABLE 6). In contrast, conditioning of the general postcoronary group led to a widening of the resting pulse pressure, with a small but significant increase of systolic pressure, and a small but significant decrement of diastolic pressure. During initial exercise at the 75% loading, the marathon runners again developed a higher systolic pressure and a wider pulse pressure than the general postcoronary population (TABLE 4). With training, both groups improved the systolic pressure that they could sustain at the 75% loading (TABLE 5). The extent of the initial ST segmental sagging was rather comparable in the two groups (Table 4). In six of the 13 marathoners, the initial response to the 75% loading was an ST sagging of more than 0.1 mV. With training, both groups tended towards less negative ST segmental voltages, although there was a suggestion of a somewhat greater improvement in the marathon participants. At the final testing, only two of this group had an ST depression
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462
of more than 0.1 mV, and in one of these two (J.R.) there had nevertheless been a very large improvement, from -0.47 to -0.12 mV. Part of the explanation in this patient was that he had been a heavy smoker. With marathon participation, he was persuaded to stop smoking; however, he later resumed the habit, to die during his sleep and two years after his last marathon; postmortem did not reveal any evidence of recent coronary occlusion or myocardial infarction and the cause of death was termed “electrical failure.”
TABLE6 HEMODYNAMIC RESPONSE WITH TRAINING. COMPARISON BETWEEN 13 MARATHONPARTICIPANTS AND 610 MEN ATTENDING THE POSTCORONARY PROGRAM. CHANGE FROM INITIAL TO MOST RECENTDATA
CHANGES IN
Marathon Mean
SD
Total Sample Mean
SD ~~
Resting blood pressure (mmHg)
Systolic Diastolic
-8.9 -9.1
214.9 212.6
+3.9 -1.0
220.8 29.2
+13.4 -2.5
221.3 214.0
+14.8 +l.5
224.9 214.2
+0.08
20.17
+0.03
f0.16
Exercise blood pressure (mmHg)
Systolic Diastolic ST segmental depression (mmHg) Voltage, at 75% load (heart rate 132.8+9.8)*
* The actual heart rate attained was closer to 70%
load.
DISCUSSION Specificity of Sample
In terms of their clinical history and previous experience of running, there is little evidence that the marathon team of the Toronto Rehabilitation Centre differs from our general postcoronary population. However, the marathon runners show less evidence of depression and development of the neurotic triad (hysteria, hypochondriasis, and psychasthenia) than is the case for our general sample. Since changes of personality scores in response to marathon preparation and participation were quite limited, we must conclude that relative to the average infarct victim the marathoners had either a less drastic psychological reaction to the acute episode or a more favorable response to early rehabilitation. None of the distance competitors had a D score higher than 23 ( a STEN value of 65 units). If this is indeed the maximum depression compatible with successful preparation for a
Kavanagh et al. : Postcoronary Runners
463
marathon contest, we would conclude that about a half of the patients with myocardial infarction could not undertake such activity. The physiological data supports the idea that the marathoners were in some respects a selected segment of our postcoronary population. The initial estimated percentage of body fat and lean mass were much as in the general sample, but the marathoners had some advantage with respect to pulse pressure, maximum tolerated systolic pressure, and aerobic power. The poorest scores found in the marathon team were an initial body fat of 24%, a lean body mass of 0.299 kg/cm, and an aerobic power of 21.7 ml/kg.min. On each of these criteria, a proportion of our general sample would have been eliminated.
Gains from Marathon Running
Granted that the marathon sample had some initial advantages of mood and physiological status relative to the general postcoronary population, it is still plain that the long distance runners made enormous physiological gains over their period of training. The most striking change was in aerobic power, the improvement in this variable averaging 5 5 % , compared with a gain of only 20% in the general postcoronary population. The infarct victim does not die of a low maximum oxygen intake as such. However, if he can improve his physical condition, then the heart rate and thus the cardiac workload for a given task is reduced. This in turn lessens the occurrence of myocardial ischemia and thus the risk of sudden death from cardiac arrest or ventricular fibrillation. The data also suggests that in marathoners conditioning lessens ST segmental sagging during exercise at 75% loadings, despite an associated increase of systolic blood pressure and an unchanged heart rate. However, this is not categoric proof that exercise has improved the myocardial blood supply through the development of collateral blood channels-other possibilities include an improvement of coronary flow secondary to the cessation of smoking, and a reduction in cardiac workload through myocardial hypertrophy or an alteration of ventricular dimensions. The favorable influence of distance running upon other “risk factors” is well established.13 The decision to engage in distance running can be a significant factor in a successful smoking withdrawal program. It is debatable whether there is much advantage in correcting abnormal blood lipids after a heart attack has occurred; however, if a patient is helped to give up smoking, this can have a major impact on the likelihood that his infarct will recur. There is no doubt that participation in the long distance contests gave these men a tremendous psychological boost. However, this is not reflected in large differences of personality scores between the marathoners and other participants in our program. This is partly because it is easier to reduce the D score in a grossly depressed patient than to change the same variable in a person whose score is only a little above the population average. Another important consideration is that the runners have seen their marathon participation as a triumph for the Centre’s program as well as for themselves; because of their unselfish attitudes, the happy experience has been shared with other more disabled patients, to the point where all have enjoyed a vicarious elevation of mood.
464
Annals New York Academy of Sciences Dangers of Marathon Participation
Since it is well established that unusual, unaccustomed, and prolonged activity can increase the immediate risks of a heart attack,“ it is most important that intending marathon participants prepare themselves thoroughly, undertaking systematic, gradual, medically supervised, and progressive long slow distance training for a number of years before considering formal competition. Each time that a substantial training distance is to be covered, a brief check must be made for warning signs such as increasing angina or unusual dysrhythmia. In our program, a complete physical examination, including a 12-lead electrocardiogram and maximal treadmill stress test is mandatory before and after a formal marathon. During the run itself, the runners must keep to a predetermined pace that has been ascertained to be within safe limits. Individual participants must be advised to compete only against themselves, stopping if there are any unusual symptoms or sensations. To date, 22 of our patients have participated in marathon events in Boston, Hawaii, and Toronto, some with times as good as 190 minutes for the 26% mile course. Happily, over 50 races have been completed without complications, either immediate or late. However, this record will be maintained only by scrupulous attention to the precautions outlined above. The one occasional disadvantage encountered by our distance runners is domestic. A wife put it in these terms: “I married a man who would spend each night in front of the television with a six-pack of beer. Now I find myself living with a running enthusiast, and I’m not sure I like it.” This woman is perhaps the exception. The majority of the wives are proud of the new achievements of their husbands. Nevertheless, the case cited does stress the importance of involving other members of the family in any program of treatment that has major social implications. Compliance with long periods of prescribed exercise is much more likely if this can be pursued as a family.
SUMMARY The characteristics of 13 postcoronary patients who have each completed one to eight marathon events were compared with data obtained on a larger sample of 610 infarct victims attending the Toronto Rehabilitation Centre. In clinical terms, the marathon group was composed of typical postcoronary patients, but personality assessments by the Minnesota Multiphasic Personality Inventory showed less depression than in many of our general sample (average normalized D scores 58 and 63, respectively). None of the marathoners had previous experience of running before their infarction, and body build was not particularly advantageous for distance events [stature ( 176.0 f 6.8 cm) was above average and body weight (75.1 10.3 kg) was average although skinfolds (13.5 & 4.1 mm) were lower than the 15.6 -t 5.0 mm found in the larger sample]. The initial aerobic power (28.0 f 4.7 ml/kg.min) of the marathoners was marginally higher than that of th? larger sample (25.1 ml/kg.min). Training led to a progressive increase of VOIlllnS, so that after 2 years the marathoners attained an average of 43.5 ml/kg.min, a 55% increase over their initial value and a 25% increase over the age-matched sedentary Toronto normal. In con-
Kavanagh et af.: Postcoronary Runners trast, the main sample of pstcoronary patients increased their
465
1,
by only
20% with training. Both at rest and during exercise at 75% of aerobic power, the initial systolic blood pressure and pulse pressure were some 1 0 mmHg larger in the marathoners than in the general sample. Training induced a 9 m m H g fall of resting pressure in the marathoners, but both the marathoners and the larger sample showed an increase of the exercise systolic pressure. ST segmental sagging was reduced in both groups over the training period, although the change in the marathoners (0.08 0.17 m V ) was somewhat larger than in the main sample (0.03 & 0.16 m V ) . Marathon participation did not induce any large changes in personality scores.
*
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