Blood pressure rise with swimming versus walking in older women: the Sedentary Women Exercise Adherence Trial 2 (SWEAT 2).

OBJECTIVE Swimming is often recommended in the prevention and treatment of hypertension. Few studies have investigated the effect of swimming training on blood pressure (BP). Our objective was to evaluate 6 months of supervised moderate swimming or walking on BP in previously sedentary, normotensive, older women. DESIGN Women aged 50-70 years (n = 116) were randomly assigned to a supervised 6-month swimming or walking programme. They were further randomized to receive usual care or a behavioural intervention package. METHODS Exercise comprised 3 sessions/week with a warm-up, cool down, and 30-min of moderate intensity walking or swimming. BP was recorded for 20 min supine, and 5 min standing. Assessments were made at 0 and 6 months. RESULTS At baseline, mean supine BP (+/- SD) was 115.7 +/- 1.3/66.8 +/- 0.7 mmHg. Swimming improved swim distance by 78.1 m (29.3%) [95% confidence interval (CI); 66.7, 89.4] and walk time by 0.58 min (3.8%) (0.41, 0.74). Walking decreased walk time by 1.0 min (6.5%) (0.81, 1.19). After adjustment for initial BP, age, hypertension treatment status and change in weight, swimming increased supine and standing systolic BP relative to walking by 4.4 mmHg (1.2, 7.5) (P = 0.008) and 6.0 mmHg (2.6, 9.5) (P = 0.001), respectively. Supine and standing diastolic BP increased by 1.4 mmHg (-0.14, 3.0) (P = 0.07) and 1.8 mmHg (-0.02, 3.5) (P = 0.05), respectively. CONCLUSION Relative to moderately paced walking, regular swimming significantly elevates BP in previously sedentary, normotensive, older women. This finding may have important implications for exercise prescription in older subjects.