Can you work out too much? What overtraining does to men’s testosterone levels

Exercise is good for you, until it isn’t. Most of us are told to move more, train regularly, and push ourselves to get stronger and fitter. But there’s a limit. And for men who regularly train at extreme intensity and volume, consistently going beyond that limit may quietly chip away at one of their most important hormones. 

It might sound counterintuitive. After all, exercise is supposed to boost testosterone, right? That’s true, in moderation. But research shows that for a small group of high-performing men, pushing the body too hard for too long, especially without enough recovery or proper nutrition, can actually lower testosterone over time.¹

This isn’t something the average gym-goer needs to worry about. The effects we’re talking about here are seen mainly in endurance athletes, competitive sportsmen, and men training at high volumes for years. If that sounds like you, it’s worth understanding what’s going on and how to protect your hormone health.

The testosterone paradox

Testosterone is a key hormone in men’s health. It fuels muscle growth, bone density, libido, energy levels, mood, and more.² Short-term exercise, like weightlifting or sprint intervals, typically gives testosterone a quick bump. But when the body is under constant physical stress like in long-distance running, elite cycling, or daily high-intensity workouts, things change.¹

In these high-load training scenarios, some men develop persistently low testosterone levels, sometimes falling below clinical thresholds. In some cases, it can last months, or even years.

The medical term for this is exercise hypogonadism, a condition where the male body’s hormone-regulating system, known as the hypothalamic-pituitary-gonadal (HPG) axis, downshifts testosterone production in response to chronic training or energy shortfalls.¹

Training hard can affect your hormonees

Historically, the medical world focused on women when talking about exercise-related hormone disruption, coining the term “Female Athlete Triad” to describe a trio of issues: disordered eating, menstrual dysfunction, and bone loss.

But in 2014, the International Olympic Committee introduced a broader term - Relative Energy Deficiency in Sport (RED-S) - to reflect the fact that men also experience similar physiological fallout from overtraining and under-fuelling.³

In men, RED-S can mean low testosterone, suppressed libido, poor recovery, brittle bones, and mental fatigue. Many won’t even notice the hormonal shift until symptoms like performance decline or mood changes start interfering with their daily life.^1,3

Two types of exercise-related testosterone drop

Research suggests there are two broad types of testosterone suppression from exercise:⁴

1. Acute and reversible: Often caused by low energy availability, such as when you’re burning more calories than you eat. This is common in sports where leanness is prized, like wrestling or endurance running. Once training intensity is reduced and nutrition improves, testosterone levels usually bounce back.

2. Chronic and adaptive: Termed the Exercise Hypogonadal Male Condition (EHMC), this form appears in men who’ve trained at high volumes for many years. They may show 25–50% lower testosterone than average, but with no apparent health issues. 

Symptoms men shouldn’t ignore

Not every man with low testosterone feels it, but many do. Some common symptoms include:²

• Fatigue and poor recovery

• Decreased libido or sexual performance

• Reduced motivation and low mood

• Trouble concentrating

• Muscle loss or poor gains from training

• Frequent injuries or weak bones

If you’re training hard and noticing these signs, it’s worth considering whether your body is waving a red flag.

What can you do?

The usual medical fix, testosterone replacement therapy (TRT), can only be prescribed under specific circumstances given the person meets a certain criteria.

But for most men, the solution lies in simple lifestyle shifts:¹

• Eat more: Especially if you’re training intensely. Prioritise protein, healthy fats, and carbs to support recovery and hormone health.

• Rest more: Schedule proper rest days. Overtraining without recovery is a fast track to hormonal imbalance.

• Monitor your load: Track how your training is affecting mood, performance, and sleep. A performance plateau or constant fatigue may mean it’s time to scale back.

• Get tested: If symptoms persist, a blood test can check testosterone and related hormones.

The numan take

Exercise is essential for good health, but like anything, it’s about balance. For most men training at a recreational level, the benefits far outweigh any risk to testosterone. However, if you’re logging extreme training hours, competing at high levels, or severely restricting calories, the equation changes. Before you double your training hours or skip another meal in the name of fitness, ask yourself: are you fuelling your body, or just burning it out? Sometimes, the most powerful move is to rest, eat, and let your hormones catch up.

References

1. Hackney AC. Hypogonadism in exercising males: Dysfunction or adaptive-regulatory adjustment? Frontiers in endocrinology. 2020;11: 11.

2. Nassar GN, Leslie SW. Physiology, testosterone. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2025.

3. Mountjoy M, Sundgot-Borgen J, Burke L, Carter S, Constantini N, Lebrun C, et al. The IOC consensus statement: beyond the Female Athlete Triad--Relative Energy Deficiency in Sport (RED-S). British journal of sports medicine. 2014;48(7): 491–497.

4. Cupka M, Sedliak M. Hungry runners - low energy availability in male endurance athletes and its impact on performance and testosterone: mini-review. European journal of translational myology. 2023;33(2).