Hitting the Wall: How Endurance Running Can Affect Testosterone

2 min readMar 26, 2024

Endurance running is fantastic for your health. It strengthens your heart, improves lung capacity, and burns serious calories. But for all its benefits, there’s a potential downside for men: too much endurance training can lead to lower testosterone levels.

Testosterone 101

Testosterone is a key male sex hormone. It influences muscle mass, bone density, sex drive, and even mood. While levels naturally decline with age, endurance athletes can experience a more significant drop.

Why Does Running Lower Testosterone?

The exact reason is still being studied, but there are a couple of leading theories:

  • Cortisol: Endurance training increases cortisol, the stress hormone. Chronically high cortisol levels are thought to suppress testosterone production.
  • Energy Availability: Long-distance running burns a lot of calories. If you’re not consuming enough to fuel your training, your body may prioritize survival over hormone production.

How Much Running is Too Much?

The magic number isn’t set in stone. It depends on factors like intensity, duration, and individual physiology. However, studies suggest that high mileage (over 60 kilometers per week) and very long runs (marathons or more) can lead to a decrease in testosterone.

Signs of Low Testosterone

Here are some signs that your training might be impacting your testosterone levels:

  • Decreased muscle mass and strength
  • Fatigue and low energy
  • Reduced sex drive
  • Difficulty sleeping

Finding Balance

Don’t ditch your running shoes just yet! Here are some ways to find balance:

  • Prioritize rest and recovery. Schedule rest days and incorporate low-intensity workouts.
  • Fuel your body. Eat a balanced diet with enough calories and protein.
  • Consider strength training. Building muscle mass can help maintain healthy testosterone levels.
  • Listen to your body. If you’re experiencing symptoms, talk to your doctor. They can assess your testosterone levels and advise on adjustments to your training or diet.

The Takeaway

Endurance running is a great way to stay healthy, but moderation is key. By being mindful of training volume, diet, and recovery, you can keep your body functioning optimally and maintain healthy testosterone levels. If you’re concerned about your hormone levels, consult a doctor for personalized advice.




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