Exercise linked to better fertility outcomes in both women and men

The analysis included data from 24,470 women and 8,068 men. In women, exercise was linked to higher levels of sex hormone-binding globulin and anti-Müllerian hormone (markers of reproductive health), as well as higher ovulation rates, pregnancy rates, and clinical pregnancy rates. In men, exercise was associated with better sperm concentration, morphology, count, and semen volume. Notably, when male partners exercised, their female partners also showed higher pregnancy rates. However, the certainty of evidence ranged from high to very low across these outcomes, with most rated as low or very low. Heterogeneity in study populations, exercise types, and intervention durations limited confidence in the pooled findings.

The mechanism linking exercise to fertility improvement likely involves multiple pathways: improved insulin sensitivity and weight management, reduced inflammation, enhanced hormonal balance, and better mitochondrial function in sperm cells. Subgroup findings suggest aerobic and resistance training may both contribute, though few trials directly compared exercise types. One key limitation is that most studies were small and measured intermediate markers (hormone levels, sperm parameters) rather than live birth rates. The heterogeneity in exercise protocols—ranging from light walking to high-intensity interval training over weeks to months—means we cannot yet identify the ideal duration, intensity, or frequency for different populations. Additionally, most participants were younger, relatively healthy, and underweight or normal-weight; effects in older age groups or those with obesity remain understudied. The certainty downgrade reflects inconsistent effect sizes and small sample sizes in many underlying trials.