The Cardiovascular Benefits of Dark Chocolate Supplementation before High-Intensity Resistance Exercise in the Early Follicular and Mid-Luteal Phases of the Menstrual Cycle

Read the full article See related articles

Discuss this preprint

Start a discussion

Listed in

This article is not in any list yet, why not save it to one of your lists.
Log in to save this article

Abstract

Background

Dark chocolate, rich in flavanols, may support vascular health by reducing arterial stiffness and blood pressure across menstrual phases. This study examined the effects of 85% dark chocolate on nitric oxide (NO) levels and vascular function during high-intensity resistance exercise in healthy women across the early follicular and mid-luteal phases.

Methods

Thirty-one healthy women (aged 20–30 years) with regular menstrual cycles completed a randomized, crossover study (conducted at National Chung Cheng University, Sep–Dec 2023). Participants consumed either 85% dark chocolate or milk chocolate (1 g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2–5) and mid-luteal (days 18–24) phases of two menstrual cycles. Finger-toe pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels were measured at rest, 2 h after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.

Results

Dark chocolate supplementation significantly increased NO levels and reduced systolic blood pressure (SBP), ftPWV, and arterial pressure volume index (API) ( p  < 0.05) compared to milk chocolate across both menstrual phases. During the early follicular phase, dark chocolate also attenuated exercise-induced increases in arterial stiffness and blood pressure ( p  < 0.05).

Conclusion

85% dark chocolate supplementation may reduce the negative vascular effects of high-intensity resistance exercise, particularly by lowering blood pressure, arterial stiffness, and API, especially in the early follicular phase. These findings suggest that dark chocolate could be a practical, non-pharmacological intervention for improving cardiovascular health in women.

Trial Registration

ClinicalTrials.gov, NCT06908941. Registered 19 March 2025 — Retrospectively registered, https://clinicaltrials.gov/study/NCT06908941 .

Article activity feed