Exercise and male fertility: how much is just right?

Physical activity is one of the best things we can do for our health. But when it comes to male fertility, more is not necessarily better. Moderate exercise improves sperm quality, while excessive exertion or the wrong choice of sport can have the opposite effect. What does the scientific research say?

When does physical activity improve fertility?

Science confirms that regular, moderate exercise has a positive effect on sperm count, motility, and shape.

• Higher levels of physical activity = more sperm:
  Men who were the most physically active had 43% higher sperm concentration than those who exercised the least.
• Even a short workout has an effect:
  Already 1.5 hours of exercise per week was associated with 42% higher sperm concentration. Men who exercised with weights for more than 2 hours per week had 25% more sperm.
• Less inflammation & healthier sperm DNA:
  Programmed exercise sessions lasting 24 weeks reduced inflammatory markers and oxidative stress , which improved sperm quality and health.
• Inactivity means a higher risk:
  Men who were inactive were more than twice as likely to be infertile . If they were also overweight, the risk increased to 2.83 times.

When does exercise harm male fertility?

Not all types of exercise are beneficial, especially not in excessive amounts. Certain sports and prolonged, intense exercise can have a negative effect.

• Too much cycling can be harmful:
  Men who cycled more than 1.5 hours per week had 34% lower sperm concentration . Those who cycled more than 5 hours per week had almost twice the risk of low sperm count and poor motility.
• Intense cycling has long-term consequences:
  Road cyclists not only had lower semen volume and poorer mobility, but the problems persisted for a month after the end of training .
• Even a long run has a price:
  Men who ran approximately 108 km per week had poorer sperm quality , while those who ran less than 56 km had normal sperm quality.
• Prolonged intense exercise affects sperm, recovery is slow:
  High-intensity exercise (120 min, 5x per week) caused problems after 6 months, and recovery took 36 weeks .
• Even professional athletes are not immune:
  Analysis of athletes showed a 5% lower proportion of normally shaped sperm compared to recreational athletes.

Excessive exercise can overheat the testicles, cause inflammation or chemical stress, which interferes with the production of healthy sperm.

Practical tips for men who want to stay fertile

• Exercise moderately. The recommendation is 150 to 300 minutes of moderate physical activity per week (brisk walking, weight training, recreational sports).
• Avoid exercise that can be harmful. When cycling, use a good seat, take breaks, combine with other activities. Long runs and extreme training should be the exception, not the rule.
• Rest is important. At least two days of rest per week and regular breaks from intense training help your body and your fertility.
• Maintain a healthy weight. Being overweight is associated with a higher risk of infertility.
• Avoid overheating. Wear breathable clothing, avoid hot baths and saunas after exercise.
• Be careful with supplements and substances. Anabolic steroids and some dietary supplements can seriously harm fertility.

In short:

Moderate physical activity has a positive effect on male fertility, as it improves concentration, mobility and sperm quality. Shorter weekly outdoor workouts and weight training bring the most benefits. On the other hand, excessive cycling, long-term running or intense training several times a week can be harmful, especially if they last for a long time without adequate rest. The key to maintaining fertility is balance: exercise regularly but wisely, give your body rest and watch for signs of overdoing it.