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.