High aerobic conditioning in older men was associated with a significantly smaller decrease in end-diastolic volume index during lower body negative pressure compared to controls (14 vs 32 ml; P<0.01).
Observational (n=18)
Does aerobic conditioning alter the orthostatic cardiovascular responses to lower body negative pressure in older men?
Increased aerobic capacity (VO2 max) in older men is associated with improved orthostatic cardiovascular responses during lower body negative pressure.
Absolute Event Rate: 14% vs 32%
p-value: p=<0.01
To determine whether aerobic conditioning alters the orthostatic responses of older subjects, cardiovascular performance was monitored during graded lower body negative pressure in nine highly trained male senior athletes (A) aged 59-73 yr maximum O2 uptake (VO2 max) = 52.4 +/- 1.7 ml.kg-1 x min-1 and nine age-matched control subjects (C) (VO2 max = 31.0 +/- 2.9 ml.kg-1 x min-1). Cardiac volumes were determined from gated blood pool scintigrams by use of 99mTc-labeled erythrocytes. During lower body negative pressure (0 to -50 mmHg), left ventricular end-diastolic and end-systolic volume indexes and stroke volume index decreased in both groups while heart rate increased. The decreases in cardiac volumes and mean arterial pressure and the increase in heart rate between 0 and -50 mmHg were significantly less in A than in C. For example, end-diastolic volume index decreased by 32 +/- 4 ml in C vs. 14 +/- 2 ml in A (P < 0.01), mean arterial pressure declined 7 +/- 5 mmHg in C and increased by 5 +/- 3 mmHg in A (P < 0.05), and heart rate increased 13 +/- 3 beats/min in C and 7 +/- 1 beats/min in A (P < 0.05). These data suggest that increased VO2 max among older men is associated with improved orthostatic responses.
Fortney et al. (Tue,) conducted a observational in Orthostatic tolerance in older adults (n=18). High aerobic conditioning vs. Untrained age-matched controls was evaluated on Decrease in end-diastolic volume index (ml) during lower body negative pressure (0 to -50 mmHg) (p=<0.01). High aerobic conditioning in older men was associated with a significantly smaller decrease in end-diastolic volume index during lower body negative pressure compared to controls (14 vs 32 ml; P<0.01).