Beetroot and Post-Workout HRV After Menopause: What We Know

Beetroot juice might help some postmenopausal women regain parasympathetic activity after aerobic exercise more quickly—but the human evidence is far too thin to call it a reliable intervention. A 2025 meta-analysis pooled just two randomized trials, involving 54 postmenopausal women with hypertension, and found a 6.68 ms improvement in post-exercise RMSSD, a heart-rate-variability measure that tracks rapid beat-to-beat vagal modulation. Both trials came from the same research group, and their results differed substantially.

The idea is biologically credible. Estrogen decline after menopause can reduce endothelial nitric oxide synthase activity and nitric oxide availability. That shift contributes to endothelial dysfunction, vascular stiffness, and higher blood pressure. Dietary nitrate, abundant in beetroot juice, can produce nitric oxide through a separate nitrate-to-nitrite-to-nitric-oxide pathway. The question is whether that biochemical detour meaningfully improves recovery after exercise. So far, the answer is: possibly, in a narrow clinical population, with major unanswered questions.

Why menopause could change post-exercise recovery

During exercise, sympathetic activity rises and parasympathetic activity falls. After exercise ends, the parasympathetic nervous system should reassert control, helping heart rate and autonomic balance recover. Heart-rate variability, or HRV, offers an indirect window into that process. RMSSD—the root mean square of successive differences between heartbeats—primarily reflects short-term parasympathetic modulation.

Estrogen supports nitric oxide production through endothelial nitric oxide synthase. After menopause, lower estrogen may reduce nitric oxide availability. Nitric oxide also affects vascular function and may influence vagal activity through central and peripheral pathways, including baroreflex regulation. Animal research cited in Benjamim et al.'s 2025 secondary analysis found that nitric oxide donors can improve baroreflex sensitivity and vagal modulation. That supports a mechanism; it does not prove that beetroot restores autonomic function in people.

Beetroot's nitrate bypasses the nitric oxide synthase enzyme. Oral bacteria convert nitrate in saliva to nitrite, and the acidic stomach environment helps convert nitrite further toward nitric oxide. This pathway makes beetroot a more targeted hypothesis for postmenopausal women than the usual "beet juice helps exercise" headline.

What the direct trials found

A 2025 systematic review and meta-analysis by Raimundo et al. identified two randomized controlled trials that tested beetroot nitrate supplementation and post-exercise HRV in postmenopausal women. Across 54 participants, beetroot supplementation favored RMSSD by 6.68 ms over control. The review did not find statistically significant pooled effects for SDNN, another time-domain HRV measure, or high-frequency power, a spectral HRV measure often used as a vagal index.

That pattern could reflect a real effect on rapid vagal fluctuations. It could just as easily reflect a small evidence base that lacked the precision to detect effects consistently across several HRV measures. With only two studies, an RMSSD-only story is a hypothesis, not a physiological conclusion.

The two trials both enrolled postmenopausal women with arterial hypertension. In the 2024 triple-blinded randomized crossover trial by Benjamim et al., participants received nitrate-rich beetroot juice or nitrate-depleted beetroot juice, an active placebo that helped isolate nitrate from beetroot's other compounds. The study examined acute and short-term supplementation around aerobic exercise and reported enhanced cardiovascular responses after exercise.

The nitrate-depleted placebo is a real design strength. It controls better than a flavorless control drink for beetroot's color, taste, and non-nitrate compounds such as betalains and polyphenols. The trial protocol, published in Trials in 2023, also confirms the triple-blind crossover design and the hypertension-specific eligibility criteria.

The other study, Benjamim et al. 2025, was a secondary analysis of a randomized crossover study in older women with hypertension. It reported faster cardiac parasympathetic recovery after exercise with dietary inorganic nitrate. Because HRV was analyzed secondarily rather than as the pre-specified primary endpoint, the result carries a greater risk of selective outcome reporting. A favorable result among several explored measures deserves less confidence than a pre-registered primary outcome.

The pooled number has sharp limits

A 6.68 ms change in RMSSD sounds precise, but its clinical meaning remains unclear. The available summary does not provide pooled baseline RMSSD values. A 6.68 ms increase could be substantial for someone starting near 12 ms and modest for someone starting near 50 ms. HRV is also a surrogate measure, not evidence that beetroot prevents cardiovascular events, improves symptoms, or extends life.

The meta-analysis reported substantial statistical heterogeneity, with I² values of 73% to 86%. That means the two trials produced meaningfully different estimates. Heterogeneity statistics are themselves unstable when only two studies exist, but the underlying disagreement still matters. Differences in dose, timing, exercise protocols, or HRV measurement could explain it. The evidence does not yet tell us which explanation is correct.

More fundamentally, both trials came from the same University of São Paulo research group. Two studies from one laboratory can show useful internal reproducibility, but they do not amount to independent replication. The participants also all had hypertension. Hypertension affects autonomic function on its own, and nitrate-related vasodilation could reduce cardiac afterload or blood pressure during recovery. Current studies cannot separate that possibility from an estrogen-related restoration of autonomic signaling.

Why dose and mouthwash may matter

The reported nitrate range across the review's included studies was 1.5 to 20 mmol, too wide to establish an effective dose for autonomic recovery in older women. For context, a 2023 cycling trial by Tan et al. used about 12.4 mmol of nitrate in healthy adults during prolonged heavy-intensity aerobic cycling. That provides a benchmark for an aerobic setting, not a validated dose for postmenopausal HRV recovery. The exact doses used in the two pooled HRV trials cannot be confirmed from the available abstracts.

The oral step is another practical complication. A 2024 double-blind crossover trial by Rowland et al. found that salivary flow influences nitrate-to-nitrite conversion. Reduced salivation, common with age and some medications, could therefore alter an individual response. Antiseptic mouthwash can disrupt the oral bacteria needed for nitrate reduction, while proton-pump inhibitors may affect the acidic gastric step. Neither pooled HRV trial reported controlling for oral microbiome status, mouthwash use, salivary flow, or proton-pump-inhibitor use.

Do broader beetroot studies settle the issue?

No. Beetroot nitrate has its most consistent exercise literature in aerobic settings, but that literature mainly involves younger and healthier participants. A 2021 systematic review of beetroot ingestion and high-intensity interval training also found context-dependent results. In contrast, a 2022 randomized trial in men performing resistance exercise found inconsistent or null effects on performance and muscle oxygenation. Nitrate does not deliver the same result across every person or workout.

Longer-term use appears feasible, at least in a related population. A 13-week pilot trial in overweight and obese older adults found incremental beetroot juice dosing acceptable and feasible. It did not measure HRV and did not specifically study postmenopausal women, so it addresses practicality rather than efficacy.

The sensible verdict

The mechanism deserves study: menopause-related reductions in nitric oxide production could plausibly make dietary nitrate more relevant to post-exercise recovery. The direct evidence does not justify treating beetroot juice as an autonomic therapy or a blood-pressure treatment. It rests on two small trials from one research group, one secondary HRV analysis, substantial between-study disagreement, and a hypertensive-only population.

For a postmenopausal woman who already wants to try beetroot juice before aerobic exercise, avoiding antiseptic mouthwash near the dose and tracking personal post-exercise HRV are reasonable experiments. They are not substitutes for prescribed hypertension care.

The next useful studies need independent laboratories, normotensive and hypertensive cohorts, confirmed nitrate doses, pre-registered HRV endpoints, and measurement of oral conversion factors. Until then, beetroot is a plausible lead—not a settled answer.