Long-Term Physical Training and Cardiovascular Dynamics in Middle-Aged Men

Abstract

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.

Cardiorespiratory adaptations induced by aerobic training in middle-aged men: the importance of a decrease in sympathetic stimulation for the contribution of dynamic exercise tachycardia

“…In the middle-aged men studied here, aerobic training was expected to cause a greater reduction in resting HR than that actually observed; the absence of a statistically significant difference in our data probably reflects the small number of subjects studied. Regardless of these considerations, the magnitude of bradycardia found in middle-aged men was comparable to that reported by others (14,15). It should be emphasized that this adaptation in HR is usually considered to be a good marker of adequate training (10,(23)(24)(25)(26) and, at least in men, an intrinsic mechanism seems to play a predominant role in the respective adaptation (27)(28)(29).…”

“…O 2 peak in our trained group was comparable to that reported by others and can reflect an important ability for adaptation at all ages (14,15,17). The major concern in exercise testing should be to determine whether the cardiorespiratory system is capable of providing the required amount of oxygen to the exercise-stressed muscles (7).…”

“…Limitations related to a reduction in maximum cardiac output appear to play an important role in age-dependent changes in aerobic transport during exercise (9)(10)(11)(12)(13). While many studies have characterized the cardiovascular responses in middleaged men, the autonomic control of HR in this particular group during exercise has received much less attention (12)(13)(14)(15)(16)(17)(18).…”

The Response of the Oxygen Pulse during a Stress Test in Patients with Coronary Artery Disease

“…The extraction of oxygen by the peripheral tissues should not fall during a progressive exercise test resulting in a decrease in the a-v02 difference. Hanson et al (8) showed the a-v02 difference to approximately double going from 3 to 9 MET. Therefore, if there is only small or no increase in the 0 2 • b e a t'1 • k g '1 as the work load increases, a fall in the stroke volume would be suggested.…”

Exercise capacity is a predictor of cardiovascular events in patients with type 2 diabetes mellitus

“…The increase in cardiac output in trained normal subjects occurs because of an increase in stroke volume. 13,29 However, the beneficial effect of physical training in persons with coronary heart disease has been attributed primarily to peripheral mechanisms 30,31 such as changing adaptive mechanisms, which increase arterial oxygen content, and to increases in muscle oxygen extraction. 8 Urinary albumin excretion is associated with left ventricular dysfunction, 32,33 and has also been reported to predict future cardiovascular events in European patients with type 2 diabetes 34,35 and to impair exercise capacity in patients with diabetes.…”