Does running impact sperm and male fertility?

We all know running offers a wide array of health benefits. But could it be affecting more than just your cardiovascular fitness? While there has been research focused on how rigorous exercise impacts female athletes, the effects on male fertility have remained less clear—a recent study published in Sports Medicine-Open hopes to change that. Here’s what you need to know about how running might influence semen quality and male fertility.

What does the research say?

The link between endurance exercise and male fertility isn’t well-researched—but scientists recently conducted a review of 13 studies involving 280 male subjects, including runners, cyclists and triathletes, to shed some light. These studies looked at various parameters like sperm concentration, motility (the ability of sperm to move or swim efficiently) and morphology (sperm size and shape).

The findings are a mixed bag. Four studies found no significant changes in sperm quality due to endurance exercise. Five studies did note changes, but these were not severe enough to impact overall fertility according to World Health Organization (WHO) standards. While some variations in semen quality were observed, overall they didn’t pose a serious threat to reproductive health.

Potential red flags

A few studies raised potential concerns, particularly for cyclists and triathletes. These athletes experienced a drop in the number of normally shaped sperm and an increase in DNA fragmentation, which could potentially affect fertility. High-intensity or high-volume training might pose some risks, especially for those starting with borderline sperm quality.

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What does this mean for runners?

For the average endurance runner, the impact on semen quality is likely minimal. Key fertility factors such as sperm concentration and motility usually stay within healthy ranges, even for those who train regularly. Problems are more likely for men already facing fertility issues or those pushing their training to extreme levels.

So, should you be worried? Probably not. While distance running can cause some changes in semen quality, they are rarely significant enough to affect overall fertility. If you’re concerned, monitoring your semen parameters and consulting a healthcare provider, especially if you’re into high-intensity or high-volume training, might help to allay your fears.