Key result
Short-term exercise and diuresis did not alter maximal or submaximal oxygen uptake in older or younger men, despite significant differences in plasma volume changes between groups.
Why the study?
Does short-term training and diuresis alter left ventricular diastolic filling and exercise oxygen uptake in older versus younger men?
RCT (n=21)
Randomly assigned
Does short-term training and diuresis alter left ventricular diastolic filling and exercise oxygen uptake in older versus younger men?
Absolute Event Rate: 8.92% vs 6.2%
p-value: p=0.038
Exercise VO2 responses are not limited by alterations in left ventricular pump function in physically fit older adults following short-term training or diuresis.
Short-term exercise and diuresis leave VO2max unchanged in older men; confirms LV pump function does not limit oxygen uptake despite plasma volume shifts.
OBJECTIVE: To determine the effect of plasma volume change with short-term training and diuresis on left ventricular diastolic filling and exercise oxygen uptake (VO(2)) in older versus younger men. METHODS: Eleven older (68 +/- 5 y) physically active (maximal oxygen uptake [VO(2max)] = 25.9 +/- 3.6 mL. kg-1. min-1) and 10 younger sedentary males (24 +/- 5 y, VO(2max) 40.5 +/- 5.0 mL. kg-1. min-1) were randomly assigned to 5 consecutive days of (1) 1 h/d high intensity stationary cycling (EXER); (2) 100 mg/d spironolactone (DIUR); and (3) exercise and diuretic (EXDI). Each treatment was separated by a 21-day washout. Doppler echocardiographic indices of left ventricular diastolic filling including peak early and atrial transmitral flow velocity and isovolumic relaxation time; percent change in plasma volume; submaximal VO(2) kinetics; and VO(2max) were determined at baseline and 48 hours after each treatment. RESULTS: Plasma volume was increased more in the young following EXER (8.92 +/- 7.6 vs. 6.2%, P = 0.038) and decreased more in the older group following DIUR (-11.5% vs. -3.54 +/- 9.0, P < 0.001). There was no significant difference between groups after EXDI. Significant changes in peak early flow velocity with EXER in older subjects were not reflected in any other changes in left ventricular diastolic filling across conditions. No changes in left ventricular diastolic filling were observed in the young group with any condition. VO(2max) and VO(2) kinetics were unchanged under all conditions from baseline in both groups. CONCLUSIONS: These results suggest that exercise VO(2) responses either at maximal or submaximal workrates are not limited by alterations in left ventricular pump function in physically fit older adults.
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Harris et al. (2003) conducted an RCT in Healthy older and younger men (n=21). Short-term training (stationary cycling) and/or spironolactone vs. Cross-over treatments was evaluated on Plasma volume change following exercise in young vs older men (p=0.038). Short-term exercise and diuresis did not alter maximal or submaximal oxygen uptake in older or younger men, despite significant differences in plasma volume changes between groups.
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