Does dark chocolate help exercise performance and muscle pain during the premenstrual phase?

Background: Hormonal fluctuations across the menstrual cycle can significantly impair physical performance, neuromuscular function, and cognitive processing in female athletes, particularly during the premenstrual phase. Emerging evidence suggests that dark chocolate (DC), rich in flavonoids, polyphenols, magnesium, and theobromine, may exert anti-inflammatory, analgesic, and neuroprotective effects. This study investigated the acute effects of 85% DC supplementation on cognitive and physical performance, as well as delayed-onset muscle soreness (DOMS), in female CrossFit ® athletes across four distinct hormonal phases. Methods: In this randomized, double-blind, placebo-controlled, crossover study, fifteen trained eumenorrheic female CrossFit ® athletes completed three intervention conditions: dark chocolate (DC), placebo (PLA), and control (CON). Participants were evaluated during four distinct menstrual phases-menstrual, follicular, luteal, and premenstrual syndrome (PMS)-over three consecutive menstrual cycles. In each phase, participants consumed 30 g/day of either DC or PLA for three days, followed by performance testing on day four. Functional and cognitive performance were assessed via the CINDY WOD, handgrip strength (HGS), and Stroop tests (reaction time and correct answer percentage, CAP). DOMS was measured using a 100 mm visual analog scale at baseline and at 0, 12, 24, 48, and 72 h post-exercise. Results: DC supplementation significantly improved functional performance (CINDY WOD) across all menstrual phases, with the greatest enhancement during PMS ( p p = 0.010 vs. control; p = 0.002 vs. placebo). Additionally, DOMS was notably reduced in the luteal phase at 12 h, 24 h, and 72 h post-exercise in the DC condition compared to the control and placebo ( p p > 0.05). Conclusions: Short-term DC supplementation may selectively enhance high-intensity functional performance and cognitive accuracy in trained female athletes, particularly during hormonally sensitive phases such as PMS. Its anti-inflammatory and neuromodulatory properties make DC a promising, non-pharmacological strategy to support female-centric recovery and performance in CrossFit ® and similar sports. Future research should explore chronic intake, mechanistic biomarkers, and individual variability across menstrual cycles.

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