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, randomized, controlled trial.
Participants: Sedentary older adults (n=115), with untreated prehypertension or mild hypertension.
Interventions: Six-month supervised aerobic and strength training.
Main Outcome Measurement: BP was assessed at rest and during each stage of a maximal graded exercise test (GXT) that determined VO2peak. General and regional fatness was assessed by anthropometry, dual-energy x-ray absorptiometry, and magnetic resonance imaging. 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 VO2peak and significantly lower measures of general and regional fatness. Also, stage-specific SBP was significantly lower at stage 3 (-9.4 vs. -1.6 mmHg, p=0.03) and stage 4 (-7.9 vs. -1.2 mmHg, p=0.03). Pooled regression analysis across all stages showed that exercisers had a 7.1 mmHg reduction in SBP, but this reduction fell short of statistical significance (p=0.12) compared to controls. A 1.0 ml/kg/min increase in VO2peak and a 1.0 cm decrease in waist circumference independently predicted a 1.0 mmHg 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. Our findings suggest that exercise training improves multiple factors that have independent influence on SBP.