Rationale: BP during exercise testing provides data about cardiovascular responses not reflected in resting BP. Exercise training increases fitness and reduces fatness, but the relationship of these parameters to change in exercise BP is unknown.

Objective: To measure the effects of 6 months of exercise training on changes in exercise BP and in relation to changes in fitness and fatness.

Methodology: Sedentary persons, 55-75 years, with untreated BP of 130-159/or 85-99 mm Hg, were randomized to exercise or a control group. BP was assessed at rest and during each stage of a graded exercise test (GXT), which measured fitness (Vo₂max). Walking began at 3 mph and 0% grade and increased 2.5% each 3 minutes, stopping at volitional fatigue. Body composition was assessed by anthropometrics, dual-energy x-ray absorptiometry, and magnetic resonance imaging. Baseline to 6-month change in BP was calculated for each GXT stage completed.

Results: The sample included 51 men and 53 women. Exercisers significantly improved fitness and reduced general and abdominal obesity. Resting SBP decreased in both groups; the reduction in resting DBP was greater in exercisers. Exercisers had greater reductions in exercise SBP compared to controls at GXT stage 3 (P = .03) and 4 (P = .03). Across all stages, the reduction in exercise BP was -7.1/-5.5 mm Hg for exercisers (P < .001 each), although this fell short of significance versus controls (P = .12/P = .07). Changes in exercise SBP were significantly correlated with changes in Vo₂max, abdominal fat, waist, % body fat, weight, and BMI. Changes in exercise DBP were significantly correlated to changes in Vo₂max and abdominal fat. Changes in exercise BP were not correlated with change in resting BP. In a our final models, a 1 mL kg^-1 min^-1 increase of Vo₂max was associated with -1.0 mm Hg decrease in exercise SBP (P = .04) and a 1-cm decrease in waist circumference was associated with -1.0 mm Hg decrease in exercise SBP (P = .001). Changes in fitness and fatness did not independently predict changes in exercise DBP.

Conclusions: While the association of increased fitness with reduced SBP was not surprising, a novel finding is that waist circumference, a marker of abdominal obesity, was independently associated with reduced exercise SBP, suggesting that exercise improves multiple factors that influence BP.