Acute and Short-Term Beetroot Juice Nitrate-Rich Ingestion Enhances Cardiovascular Responses Following Aerobic Exercise in Postmenopausal Women with Arterial Hypertension: A Triple-Blinded Randomized Controlled Trial

Background: The increase in blood pressure (BP) levels in the postmenopausal period can be partly explained by the decrease in nitric oxide synthases (NOS). Objective: To investigate the acute and one-week effects of beetroot juice nitrate-rich (BRJ-NO3-rich) ingestion on cardiovascular and autonomic performance in response to submaximal aerobic exercise in postmenopausal women with systemic arterial hypertension (SAH) who are physically inactive. Methods: Fourteen postmenopausal women with SAH [mean (SD) age: 59(4) y; BMI (kg/m2): 29.2(3.1)] completed submaximal aerobic exercise bouts after an acute and a one-week intervention with BRJ in a placebocontrolled, randomized, triple-blind, crossover design. Participants ingested either BRJ (800 mg of NO3- ) or placebo acutely and drank either BRJ (400 mg of NO3- ) or placebo every day for the next six days. After two and 1/2 hours, they performed a session of aerobic submaximal aerobic exercise, and their systolic BP (SBP) and diastolic BP (DBP), flow-mediated dilation (FMD), heart rate (HR) recovery, and HR variability were measured. Results: In the post-exercise recovery period, SBP dropped significantly in the BRJ-NO3- rich group (-9.28 mmHg [95%CI: -1.68 to -16.88] ES: -0.65, p = 0.019) compared to placebo after acute ingestion. The FMD values increased after acute BRJ-NO3-rich on post-exercise (3.18 % [0.36 to 5.99] ES: 0.87, p = 0.031). After the oneweek intervention, FMD values were higher in the BRJ-NO3- rich group before (4.5 % [1.62 to 7.37] ES: 1.21, p = 0.005) and post-exercise measurements (4.2 % [1.52 to 6.87] ES: 1.22, p = 0.004) vs. placebo. HRV indices with remarkable parasympathetic modulation to heart recovered faster on the BRJ-NO3-rich group than placebo group. No between-group differences were identified in values of HR post-exercise recovery in the 30s, 60s, 120s, 180s, and 300s. Conclusions: Acute and short-term BRJ-NO3-rich ingestion may enhance cardiovascular and autonomic behavior in response to aerobic exercise in postmenopausal women diagnosed with SAH. Clinical trial registry number: https://clinicaltrials.gov/ct2/show/NCT05384340.