Cycling is generally not considered a significant factor in fertility issues, according to fertility specialist Prof Colin Duncan of the University of Edinburgh. He explains that for most people, moderate cycling poses little to no risk to reproductive health.

For women, cycling is unlikely to affect fertility unless it is performed at very high intensity levels comparable to elite athletic training. Such extreme physical activity can reduce body fat to levels that disrupt ovarian function, potentially leading to missed menstrual periods and diminished fertility.

Men’s fertility concerns related to cycling primarily involve prolonged sitting on a bicycle saddle, which can elevate the temperature around the testicles. Since sperm production is optimized at a cooler temperature, this heat increase could potentially lower sperm count. Testicles are naturally positioned outside the body to maintain this cooler environment, underscoring the importance of temperature regulation for sperm development.

However, Prof Duncan notes that routine cycling is unlikely to cause significant changes in sperm count for most men. The testicles typically produce a surplus of sperm, meaning a slight reduction in quantity generally does not hinder fertility. He suggests that only men who already have borderline sperm counts might experience a noticeable effect from extensive cycling.

In clinical practice, Duncan considers lifestyle factors, such as smoking, alcohol consumption, and exposure to heat sources like saunas, when assessing sperm samples. He advises moderation of such behaviors if fertility problems are detected, recommending lifestyle adjustments to improve reproductive outcomes.

Overall, while extreme cycling and other lifestyle factors can influence fertility, regular cycling within typical levels poses minimal risk to both male and female reproductive health.