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Comparison of treadmill and bicycle ergometer exercise in middle-aged males
Annotations Comparison of treadmill and bicycle ergometer exercise in middle-aged males
Comparisons of bicycle and treadmill exercise tests are available in young adults but not for 40 to 65-year-olds who are most frequently given exercise stress tests in clinical practice. Claims of advantages of one type of test over another are often made without direct evidence, a common one being that North Americans cannot be maximally stressed with the bicycle. We have compared the results of maximal bicycle and treadmill tests in 305 normal males 42 to 70 years of age {mean age 56). The Bruce protocol was used on the treadmill, and on the calibrated electric bicycle ergometer, subjects worked at about 450 kpm/minute for 6 minutes immediately followed by 600 to 900 kpm/minute for six minutes, after which the load was increased by 300 kpm/minute each minute, with considerable encouragement, until severe fatigue. Mean maximal heart rates at ages 40 to 49, 50 to 59, and 60 to 69 were 179, 169, and 157 beats/minute, respectively, and were identical for each exercise. Two minutes after completion of the exercise, sitting heart rates were 3 per cent higher after bicycle exercise (p < .01). Predicted maximal oxygen uptakes for treadmill exercise were 37, 34, and 31 ml./Kg./minute for the three age groups, and directly determined mean values were about 1 nfl./Kg./minute below the predicted values. Predicted maximal oxygen uptakes for bicycle exercise were 20 to 40 per cent below that predicted for the treadmill using the Astrand nomogram, partly because the nomogram underpredicted directly measured maximal oxygen uptake values by about 20 per cent. The mean maximal products of systolic blood pressure times heart rate were 7 per cent lower for treadmill exercise. The mean maximal metabolic load expressed in equivalents o f oxygen uptake was 6 per cent higher for treadmill work. In response to a questionnaire, 73 per cent of the subjects indicated preference for the treadmill test, and the bicycle test was felt to have caused more generalized fatigue, more leg fatigue, and was less easy to complete by about 60 per cent Of the subjects:
The heart rate times systolic blood pressure product was 5 per cent higher for bicycle exercise (p < .05), but the difference may have been due to problems of obtaining the pressure during maximal treadmill exercise. Two bicycle tests performed one year apart gave identical measures of maximal heart rates as did two treadmill tests. Two bicycle tests performed one year apart gave identical mean maximal work loads (1,315 kpm/minute) and two treadmill tests performed one year apart gave mean endurance times t h a t were almost identical, 10.9, 9.7, and 8.8 minutes for the three age groups. It was concluded that both bicycle and treadmill exercises were suitable for maximal exercise tests in middle-aged North American males who are not accustomed to either exercise test, nor to bicycle exercise in daily life. Both tests gave consistent results when performed one year apart. Both tests caused similar cardiovascular distress as evidenced by equal maximal heart rates and equal systolic products. Three out of four subjects preferred the treadmill exercise, the three technicians involved favored using the treadmill as a test and they did not have to encourage the subjects as much. There was an important difference in the predicted maximal oxygen uptake, with bicycle values being well below treadmill values. Predictions of aerobic power cannot be compared unless identical tests are used. While the results in these normal men may not be exactly transferable to cardiac patients, there seems to be little practical difference in the level of cardiac stress that can be imposed with either the treadmill or bicycle, while each test has other advantages or disadvantages compared to the other. Gordon R. Cumming, M.D. Section of Cardiology Children's Centre 685 Bannatyne A re. Winnipeg, Manitoba R3E OWl Canada
Factors influencing the resumption of work, sexual activity, and driving following acute myocardial infarction
Although most patients who survive their first myocardial infarction should be able to resume a virtually normal lifestyle within three to four months of the illness, between 40 to 60 per cent of these patients have not returned to work by this
American Heart Journal
time.' However, this delay is rarely due to physical incapacity as a result of heart failure, incapacitating angina, or dyspnea. Similarly, occupations that demand an excessive physical load, unsympathetic attitudes of employers, or unsuitable
261
Comparisons of bicycle and treadmill exercise tests are available in young adults but not for 40 to 65-year-olds who are most frequently given exercise stress tests in clinical practice. Claims of advantages of one type of test over another are often made without direct evidence, a common one being that North Americans cannot be maximally stressed with the bicycle. We have compared the results of maximal bicycle and treadmill tests in 305 normal males 42 to 70 years of age {mean age 56). The Bruce protocol was used on the treadmill, and on the calibrated electric bicycle ergometer, subjects worked at about 450 kpm/minute for 6 minutes immediately followed by 600 to 900 kpm/minute for six minutes, after which the load was increased by 300 kpm/minute each minute, with considerable encouragement, until severe fatigue. Mean maximal heart rates at ages 40 to 49, 50 to 59, and 60 to 69 were 179, 169, and 157 beats/minute, respectively, and were identical for each exercise. Two minutes after completion of the exercise, sitting heart rates were 3 per cent higher after bicycle exercise (p < .01). Predicted maximal oxygen uptakes for treadmill exercise were 37, 34, and 31 ml./Kg./minute for the three age groups, and directly determined mean values were about 1 nfl./Kg./minute below the predicted values. Predicted maximal oxygen uptakes for bicycle exercise were 20 to 40 per cent below that predicted for the treadmill using the Astrand nomogram, partly because the nomogram underpredicted directly measured maximal oxygen uptake values by about 20 per cent. The mean maximal products of systolic blood pressure times heart rate were 7 per cent lower for treadmill exercise. The mean maximal metabolic load expressed in equivalents o f oxygen uptake was 6 per cent higher for treadmill work. In response to a questionnaire, 73 per cent of the subjects indicated preference for the treadmill test, and the bicycle test was felt to have caused more generalized fatigue, more leg fatigue, and was less easy to complete by about 60 per cent Of the subjects:
The heart rate times systolic blood pressure product was 5 per cent higher for bicycle exercise (p < .05), but the difference may have been due to problems of obtaining the pressure during maximal treadmill exercise. Two bicycle tests performed one year apart gave identical measures of maximal heart rates as did two treadmill tests. Two bicycle tests performed one year apart gave identical mean maximal work loads (1,315 kpm/minute) and two treadmill tests performed one year apart gave mean endurance times t h a t were almost identical, 10.9, 9.7, and 8.8 minutes for the three age groups. It was concluded that both bicycle and treadmill exercises were suitable for maximal exercise tests in middle-aged North American males who are not accustomed to either exercise test, nor to bicycle exercise in daily life. Both tests gave consistent results when performed one year apart. Both tests caused similar cardiovascular distress as evidenced by equal maximal heart rates and equal systolic products. Three out of four subjects preferred the treadmill exercise, the three technicians involved favored using the treadmill as a test and they did not have to encourage the subjects as much. There was an important difference in the predicted maximal oxygen uptake, with bicycle values being well below treadmill values. Predictions of aerobic power cannot be compared unless identical tests are used. While the results in these normal men may not be exactly transferable to cardiac patients, there seems to be little practical difference in the level of cardiac stress that can be imposed with either the treadmill or bicycle, while each test has other advantages or disadvantages compared to the other. Gordon R. Cumming, M.D. Section of Cardiology Children's Centre 685 Bannatyne A re. Winnipeg, Manitoba R3E OWl Canada
Factors influencing the resumption of work, sexual activity, and driving following acute myocardial infarction
Although most patients who survive their first myocardial infarction should be able to resume a virtually normal lifestyle within three to four months of the illness, between 40 to 60 per cent of these patients have not returned to work by this
American Heart Journal
time.' However, this delay is rarely due to physical incapacity as a result of heart failure, incapacitating angina, or dyspnea. Similarly, occupations that demand an excessive physical load, unsympathetic attitudes of employers, or unsuitable
261