Rj. Spina et al., DIFFERENCES IN CARDIOVASCULAR ADAPTATIONS TO ENDURANCE EXERCISE TRAINING BETWEEN OLDER MEN AND WOMEN, Journal of applied physiology, 75(2), 1993, pp. 849-855
Recent studies have shown that people in their seventh decade are able
to adapt to exercise training with an increase in maximal O2 uptake (
Vo2max) similar in relative magnitude to that observed in young people
. The purpose of this study was to determine the relative contribution
s of increases in stroke volume and O2 extraction to the training-indu
ced increase in Vo2max. in older men and women. Fifteen men [63 +/- 3
(SE) yr] and 16 women (64 +/- 3 yr), in good health, participated in 9
-12 mo of endurance exercise training at 70 to 85% of maximal heart ra
te for 45 min/day, 4 days/wk. Vo2max increased 19% (2.35 +/- 0.1 to 2.
8 +/- 0.1 l/min; P < 0.01) in the men and 22% (1.36 +/- 0.1 to 1.66 +/
- 0.1 l/min; P < 0.01) in the women in response to training. In the me
n, stroke volume during maximal exercise was 15% higher after training
, and this increase accounted for 66% of the increase in Vo2max. The r
emainder of the increase in Vo2max was accounted for by a 7% greater a
rteriovenous O2 content difference during maximal exercise. In contras
t, training resulted in no change in stroke volume in women, in whom t
he entire increase in Vo2max was accounted for by a greater arterioven
ous O2 content difference (12.2 +/- 0.4 before vs. 14.4 +/- 0.4 ml O2/
100 ml blood after; P < 0.01) during maximal exercise. There were no c
hanges in these variables in the control subjects. The mechanisms resp
onsible for the training-induced increase in Vo2max in the older men w
ere similar to those found in young people. However, the older women a
dapted to the exercise training with an increase in O2 extraction with
no increase in cardiac output.