Watermelon extract reduces blood pressure but does not change sympathovagal balance in prehypertensive and hypertensive subjects

Previous studies have shown that watermelon extract reduces blood pressure through vasodilation. However, those studies have not verified whether sympathetic nervous activity is influenced by watermelon extract. This study aimed to evaluate the effect of supplementation with watermelon extract for 6 weeks on blood pressure and sympathovagal balance of prehypertensive and hypertensive individuals. Forty volunteers participated in a randomized, double-blind, experimental and placebo-controlled study. They consumed 6g of watermelon extract daily (n=20; age 48.7 +/- 1.9 years, 10 men) or a placebo (n=20; age 47.4 +/- 1.2 years, 11 men) for 6 weeks. Blood pressure and cardiac autonomic modulation were measured. Watermelon extract promoted a significant reduction in systolic (137.8 +/- 3.9 to 126.0 +/- 4.0mmHg, p<0.0001) and diastolic (79.2 +/- 2.2 to 72.3 +/- 2.0mmHg, p<0.001) blood pressure, but showed no differences compared to the placebo group. This significant reduction in blood pressure occurred without a significant change in sympathovagal balance from the beginning (1.7 +/- 0.1) to the end of the study (1.7 +/- 0.4). In conclusion, supplementation with watermelon extract reduces systolic and diastolic blood pressure in prehypertensive and hypertensive individuals, but does not alter the cardiac autonomic modulation of these individuals.