Effects of Watermelon Supplementation on Aortic Hemodynamic Responses to the Cold Pressor Test in Obese Hypertensive Adults

BACKGROUND Cold-induced increases in aortic blood pressure (BP) may cause adverse cardiac events in hypertensives by increasing ventricular afterload. L-citrulline supplementation reduces BP at baseline and during the cold pressor test (CPT), but the effect on wave reflection (augmentation pressure (AP) and index (AIx)) is controversial. Our aim was to assess the effect of L-citrulline-rich watermelon supplementation on aortic hemodynamic responses to CPT in hypertensive adults. METHODS Brachial systolic BP (bSBP) and aortic systolic BP (aSBP), AP, AIx, AIx adjusted to 75 beats/min (AIx75), reflection time (Tr), first (P1) and second systolic peak (P2; wave reflection magnitude), heart rate (HR), and systolic time index (STI; myocardial oxygen demand) at baseline and during CPT and magnitude of the response from baseline to CPT were evaluated in 13 individuals (10 women; 57 +/- 1 year; bSBP 151 +/- 5 mm Hg). Participants were randomized to a 6-week watermelon or placebo supplementation in a crossover design. RESULTS Watermelon reduced (P < 0.05) bSBP, aSBP, P1, and P2 at baseline and CPT compared with placebo; thus, increases from baseline to CPT were unaffected. Watermelon did not affect AP, AIx, AIx75, and STI at baseline but decreased (P < 0.05) AP and STI during CPT and the increases in AP (similar to 5 mm Hg) and AIx75 (similar to 7.3%) from baseline to CPT. CONCLUSIONS Watermelon supplementation reduced aortic BP and myocardial oxygen demand during CPT and the magnitude of the cold-induced increase in wave reflection in obese adults with hypertension. Watermelon may provide cardioprotection by attenuating cold-induced aortic hemodynamic responses.