Comparison of the Circulatory Response to Upright Exercise in 25 "Normal" Men and 9 Distance Runners

Although "of essential physiological interest" (Astrand, 1956), studies of physical performance comparing the circulatory and ventilatory responses to exercise of normal men and athletes have been regrettably few in number. Likewise, investigations of the effects of physical training on per- formance have been reported only infrequently. Inconsistencies in published results may be accounted for by several factors, including study of only 2 or 3 subjects, employment of too few work loads to delineate fully the range from minimal to maximal exercise, and use of recumbent rather than upright exercise position. Freedman et al. (1955) studied the supine cardiac output response of 3 cross-country runners at three or four levels of exercise, the highest oxygen utilizations being 2 0 1./min. Of the 3 subjects, 2 were studied before and after training. Bevegard, Holmgren, and Jonsson (1963) reported circulatory studies in 8 cyclists exercising in both supine and sitting position, but only two levels of work were employed. These results were compared with two earlier studies in non-athletic normal subjects (BevegArd, Holmgren, and Jonsson, 1960; Holmgren, Jonsson, and Sj6strand, 1960a), but the work loads in these two latfer groups were not strictly comparable with those of the athletes. A review of these findings is included in BevegArd's thesis (1962). Hemodynamics during graded supine exercise in 9 athletes, 13 men, and 4 women have been reported by Musshoff, Reindell, and Klepzig (1959a), and Musshoff et al. (1959b). Holmgren (1956) studied 35 well-trained cyclists to find the effect of exercise on arterial, venous, and cesophageal pressures, while a later report by the same author (Holmgren et al., 1960b) discussed the effects of training on heart rate, work capacity, and other parameters. Prolonged severe treadmill exercise was employed by Wang, Marshall, and Shepherd (1960) reported the circulatory effects of posture change and graded exercise in 3 athletes, while an abstract by the same author (Wang et al., 1961) compared the cardiac response to exercise in 5 unconditioned men and 5 athletes. An as yet unpublished investigation by the same group (Wang et al., 1965) will present the effects of a systematic conditioning programme on the cardiovascular function of 7 sedentary college men. Many of Astrand's publications (1952, 1956) deal primarily with the ventilatory and metabolic responses to exercise in normal subjects and athletes, and Jongbloed (1962) has discussed the effects of training on oxygen utilization and carbon dioxide elimination in championship skaters. Fourteen sedentary subjects were studied by Frick, Konttinen, and Sarajas (1963) before and after two months of army basic training conditioning.