Cardiovascular Determinants of Maximal Stroke Volume in Healthy Older Men of Various Fitness Levels

PURPOSE: Left ventricular (LV) compliance, total blood volume (TBV) and total systemic vascular resistance (SVR) are important determinants of stroke volume during exercise. However, these parameters have not been concomitantly collected in a cohort of healthy adults of various fitness levels to determine their individual or collective effect on maximal stroke volume (SV sub(max)). METHODS: Maximal oxygen uptake (VO sub(2)max) (Douglas bags), SV sub(max) (C sub(2)H sub(2) rebreathing), TBV (carbon monoxide rebreathing) and measures of LV volume (echocardiography) and filling pressure (right heart catheterization) were collected at supine rest and during increased preload (saline infusion +30 ml/kg) in 55 healthy older (>60 years) men. Subjects ranged from sedentary men who had consistently (>20 years) performed less than 2 exercise training sessions/wk to Masters Athletes who performed 6 or more sessions/wk plus regular competitions. RESULTS: SVmax relative to fat free mass (FFM) was positively related with VO2max (r=0.67, p