Pf. Mclaren et al., STROKE VOLUME RESPONSE TO CYCLE ERGOMETRY IN TRAINED AND UNTRAINED OLDER MEN, European journal of applied physiology and occupational physiology, 75(6), 1997, pp. 537-542
The aims of this study were threefold: (1) to investigate the stroke v
olume (SV) response of trained older male cyclists [Cyclists: 65 (2.1)
years; n = 10] during incremental cycle ergometry (20 W.min(-1)); (2)
to determine the SV dynamics and total peripheral resistance response
of untrained, but healthy and active older male controls [Controls: 6
6(1.1) years; n = 10]1 (3) to compare the maximum oxygen consumption (
(V) over dot O-2max) and SV response of trained older male runners [Ru
nners: 65 (3.4) years; n = II] with that of age-matched Cyclists. Impe
dance cardiography was used to assess the response of cardiac output (
GO), SV and total peripheral resistance to exercise involving cycle er
gometry. The mean (V) over dot O-2max of the trained Cyclists [54 (1.6
) ml.kg(-1).min(-1)]was significantly higher (P < 0.05) than that of t
he Runners [48 (3.9) ml.kg(-1).min(-1)], whereas both groups possessed
a significantly higher (V) over dot O-2max than the Controls [28 (1.3
) ml.kg(-1).min(-1)]. During exercise, at a heart rate of 90 beats.min
(-1), the SV of the Cyclists increased by 41 %, that of the Runners in
creased by 47%, and that of the Controls increased by 31%. However, th
e Cyclists' and Runners' SV response was significantly greater than th
at of the Controls. The SV for cyclists and controls peaked at 30% of
(V) over dot O-2max. This early increase in SV was a major factor unde
rlying the increase in CO during exercise in both the trained and the
untrained subjects. In addition, all three groups showed a significant
decrease in total peripheral resistance throughout exercise. The find
ing that older male runners possessed a large exercise SV and high (V)
over dot O-2max suggests that run training results in enhanced cardio
vascular performance during cycle ergometry.