Decreased exercise blood pressure in older adults after exercise training: contributions of increased fitness and decreased fatness

Objective: To describe the contribution of changes in fitness and fatness resulting from exercise training on changes in submaximal exercise blood pressure (BP) during treadmill testing. Design and setting: Prospective, randomised, controlled trial. Participants: Sedentary older adults (n = 115) with untreated prehypertension or mild hypertension. Intervention: Six-month supervised aerobic and strength training. Main outcome measurement: Systolic BP (SBP) was assessed at rest and during each stage of a maximal graded exercise test (GXT) that determined VO(2) peak. General and regional fatness was assessed by anthropometry, dual-energy x-ray absorptiometry and MRI. BP changes were calculated for each GXT stage, and multivariate regression models were used to describe the association of changes in exercise BP with changes in fitness and fatness. Results: After training, exercisers versus controls had significantly increased VO(2) peak and significantly lower measures of general and regional fatness. Also, stage-specific SBP was significantly lower at stage 3 (-9.4 vs -1.6 mm Hg, p = 0.03) and stage 4 (-7.9 vs -1.2 mm Hg, p = 0.03). Pooled regression analysis across all stages showed that exercisers had a 7.1 mm Hg reduction in SBP, but this reduction fell short of statistical significance (p = 0.12) compared with controls. A 1.0 ml/kg/min increase in VO(2) peak and a 1.0 cm decrease in waist circumference independently predicted a 1.0 mm Hg decrease in exercise SBP (p = 0.04 and p = 0.001, respectively). Conclusions: Decreased exercise SBP was independently associated with decreased waist circumference, a marker of abdominal obesity and increased fitness. These findings suggest that exercise training improves multiple factors that have an independent influence on SBP.