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We have tested the hypothesis that there is a positive relation between arterial elasticity and physical working capacity (PWC) at a given age. The subjects were 28 young men, 16-18 yr old. Arterial elasticity was evaluated by measuring the carotid to femoral pulse-wave velocity (c) at rest. The slope, S(c) of the relation between c and the diastolic blood pressure was studied during a cold pressor test to test vascular reactivity. The relationship between heart rate (HR) and work load was determined using a cycle ergometer; the variables measured were the slope of this relation S(PWC) and the power output at a HR of 170 min-1 (PWC170). The PWC170 ranged from 1.8 to 4.6 W/kg, and values of c ranged from 3.9 to 6.8 m/s. A strong inverse linear relation was found between c and PWC170 (r = -0.76), whereas the HR at rest was positively related to both c (r = 0.68) and PWC170 (r = 0.74). There was no relationship between HR at rest and the slopes S(c) and S(PWC); the latter two variables depend mainly on the sympathetic response. These results show the importance of the intrinsic mechanical properties of the cardiovascular system, particularly arterial elasticity, in human adaptations to muscular exercise.

The arterial pulse wave velocity is determined to a large extent by the arterial elastic modulus. We tried to assess the importance of this parameter in cardio-vascular adaptation to exercise by measuring pulse wave velocity (c) in 45 sedentary subjects and 28 competitive cyclists whose ages ranged from 14 to 47 years. The measurements were performed at rest and during the recovery phase after ergometric exercise. At constant diastolic pressure, a positive linear relationship was demonstrated between c and age in both the sedentary and trained subjects. The slope of this relation was significantly different in the two groups. During the recovery phase, at constant diastolic pressure, a linear relationship was also established between c and the relative increase in systolic pressure in the sedentary group classified into six age subgroups. The slope of this relation increased with age. The part taken by diastolic flow velocity during exercise in the increase in c was demonstrated in 8 subjects by simultaneous Doppler ultrasonic recording of contra-lateral femoral arterial velocity. Nevertheless diastolic flow in exercise could not explain entirely the observed increase in c. An increase in arterial elasticity modulus during exercise should be postulated in order to explain the concomitant increase in arterial pulse wave velocity.