The effect of regular aquatic exercise on blood pressure: A meta-analysis of randomized controlled trials

Background No meta-analysis has examined the effect of regular aquatic exercise on blood pressure. The purpose of this study was to perform a meta-analysis to evaluate the effects of regular aquatic exercise on blood pressure. Design A meta-analysis of randomized controlled trials. Methods Databases were searched for literature published up to April 2017. The randomized controlled trials analysed involved healthy adults, an intervention group that only performed aquatic exercise and a control group that did not exercise, no other intervention, and trials indicated mean systolic blood pressure or diastolic blood pressure. The net change in blood pressure was calculated from each trial, and the changes in blood pressure were pooled by a random effects model, and the risk of heterogeneity was evaluated. Subgroup analysis of subjects with hypertension, subjects who performed endurance exercise (or not), and subjects who only swam (or not) was performed, and the net changes in blood pressure were pooled. Results The meta-analysis examined 14 trials involving 452 subjects. Pooled net changes in blood pressure improved significantly (systolic blood pressure -8.4 mmHg; diastolic blood pressure -3.3 mmHg) and the changes in systolic blood pressure contained significant heterogeneity. When subjects were limited to those with hypertension, those who performed endurance exercise and subjects who did not swim, pooled net changes in systolic and diastolic blood pressure decreased significantly, but the heterogeneity of systolic blood pressure did not improve. Conclusion Like exercise on land, aquatic exercise should have a beneficial effect by lowering blood pressure. In addition, aquatic exercise should lower the blood pressure of subjects with hypertension, and other forms of aquatic exercise besides swimming should also lower blood pressure.