Long-Term Physical Training and Cardiovascular Dynamics in Middle-Aged Men
The effects of a 7-month physical training program on the physiological responses to exercise and work capabilities of seven middle-aged, sedentary men have been evaluated. Testing involved bicycle ergometry and interval treadmill walking, as well as pre- and postconditioning hemodynamic investigations during five levels of treadmill walking up to a 25% grade.
Significant alterations of several parameters were observed in the trained state. Resting and exercise bradycardia were marked, the lowest heart rate registered being 49/min. Maximal physical working capacities and maximal oxygen uptakes were uniformly increased with group means of + 22 and + 18%, respectively. Work load capacities at heart rates 130, 150, and 170 were also augmented.
Resting and exercise cardiac output for a given oxygen uptake declined and produced relative hypokinesis. Stroke volume was greater at moderate and heaviest work loads. Cardiac minute work was reduced despite stroke volume increments.
Pulse wave and arterial pressure analyses indicated that tension-time index and ejection-time index were markedly reduced, while maximal pressure derivative and ventricular ejection rate were increased.
It is concluded that aside from subjective enhancement of well-being, a well-planned physical training program for middle-aged men can develop beneficial economy and efficiency of myocardial function and the oxygen transport system.
- © 1968 American Heart Association, Inc.