Relative Energy Deficiency in Sport in Men: Signs Coaches Miss (Sleep, Mood, Libido, Recurrent Injuries)

Many coaching conversations about poor recovery start with training load, “mental toughness,” or discipline. But a growing number of male athletes are not breaking down because they lack grit—they are breaking down because their bodies are repeatedly asked to do high-output work on a low-fuel budget.

Relative Energy Deficiency in Sport is a syndrome that develops when an athlete’s energy intake consistently fails to match the combined demands of training, daily living, and basic physiological function. The International Olympic Committee describes it as a multi-system condition driven by problematic low energy availability, affecting health and performance across multiple body systems.

For men, the “headline” symptom is rarely obvious. There is no menstrual cycle as a visible warning signal. Instead, the earliest alarms tend to be subtle: a sleep pattern that changes, a mood that flattens, libido that drops, injuries that keep recurring, or a resilient athlete who suddenly becomes fragile.

This article is written for coaches, strength and conditioning staff, athletic trainers, and sports-minded parents who want to catch the quiet pattern early—before the athlete ends up with repeated stress injuries, persistent fatigue, or hormone and bone consequences that can follow them long after the season.

Low energy availability occurs when the calories left over after training are not enough to support normal physiology. It can happen intentionally (dieting, weight-cutting, “getting lean”), unintentionally (busy schedule, appetite suppression after hard sessions, poor access to food), or through a combination of both.

Importantly, Relative Energy Deficiency in Sport is not limited to athletes with eating disorders. It can occur in high-achieving, highly compliant athletes who are simply under-fuelling relative to what they expend.

When energy availability stays too low for too long, the body adapts by “downshifting” systems it considers non-essential for immediate survival. That protective strategy may keep an athlete functioning day-to-day, but it comes at a cost:

• Hormonal function can be suppressed (including testosterone-related pathways in men).
• Bone remodeling can shift toward higher risk of bone stress injury.
• Sleep and mood can change through stress-hormone and neurotransmitter effects.
• Immune function and recovery can weaken, increasing illness and injury risk.

Coaches miss it for three reasons:

1. The athlete still performs—until they don’t. Early on, athletes can maintain speed, power, or race results through adrenaline, stimulants, and sheer work ethic.
2. The symptoms look “normal” in sport culture. Irritability, light sleep, low libido, nagging injuries, and low mood are often normalized as part of hard training.
3. The athlete may look lean and “fit,” which is praised. Many environments reward leanness and body composition targets without equal emphasis on fueling and recovery safeguards. The International Olympic Committee specifically discusses safe, athlete-centered approaches to body composition assessment to reduce harm.

Sleep disruption is one of the most common early clues—and one of the easiest to dismiss.

Patterns coaches should notice:

• The athlete falls asleep but wakes up too early (especially 3–5 a.m.) and can’t return to sleep.
• Restless, light sleep after evening training sessions.
• Increased reliance on caffeine to feel normal.
• A new pattern of vivid dreams, night sweats, or “wired but tired” evenings.
• A wearable showing declining sleep efficiency or rising resting heart rate over weeks.

Why it can happen:

With inadequate energy availability, the body may elevate stress responses, alter thyroid signaling, and disrupt normal recovery physiology. The athlete may feel exhausted, but the nervous system stays in a semi-activated state—especially if training is intense and fueling is low.

Coaching takeaway:

If sleep changes coincide with increased training load, weight loss, or a “clean eating” phase, treat it as a performance variable—not a lifestyle flaw.

Relative Energy Deficiency in Sport can show up as a psychological and behavioral change before it looks like a physical one. Mood shifts are not always dramatic. They can look like a slow dimming.

Watch for:

• Irritability, shorter fuse, or conflict with teammates
• Flat mood, low enthusiasm, “not caring” about sessions
• Increased anxiety, especially around food, rest days, or body image
• Obsessive training behaviors: adding extra cardio, refusing deload weeks
• Social withdrawal and reduced spontaneity

The International Olympic Committee’s model emphasizes that low energy availability affects multiple systems, including psychological health and performance outcomes.

Coaching takeaway:

When mood changes happen alongside fatigue and recurring minor injuries, it’s a red flag for under-recovery and possible low energy availability—not simply motivation.

Many male athletes won’t mention low libido or erectile changes unless directly asked—and even then, they may minimize it.

Clues that can indirectly point to libido-related suppression:

• The athlete reports “no interest” in dating/sex compared with baseline
• Morning erections become infrequent
• They describe feeling emotionally flat, low drive, or unusually apathetic
• They struggle to gain strength despite consistent training and good sleep effort

Research and clinical reviews in male endurance athletes link low energy availability with lower testosterone and endocrine disruption, with potential downstream effects on bone and performance.

Coaching takeaway:

Libido changes are not a “personal weakness.” In the context of heavy training and weight control, they can be an important physiological signal that the body is conserving energy.

Injury patterns are often where Relative Energy Deficiency in Sport finally becomes visible—because injuries force time off.

Common patterns in men:

• Bone stress injuries (stress reactions, stress fractures), especially with a history of dieting, high mileage, or sudden load increases
• Recurrent tendinopathy that improves briefly then returns
• Muscle strains that appear “random” or keep recurring
• Slow healing timelines, repeated niggles, frequent “tightness” that never resolves

Recent research in male athletes supports associations between low energy availability surrogates, Relative Energy Deficiency in Sport outcomes, and injury risk—including bone stress injuries.

Coaching takeaway:

If an athlete has repeated injuries plus changes in sleep/mood or weight, stop assuming it’s just biomechanics. Consider fueling and recovery physiology as primary drivers.

Relative Energy Deficiency in Sport rarely travels alone. It tends to create a constellation.

• Declining performance at the same effort
• Higher perceived exertion for routine workouts
• Trouble hitting high-intensity targets
• Needing longer warm-ups to feel “normal”
• Plateaus in strength and power despite consistency

• Unexplained weight loss or “leaning out” faster than expected
• Frequent colds, lingering coughs, slow recovery from minor illness
• Gastrointestinal issues: bloating, constipation, appetite loss, or food rigidity
• Cold intolerance, always wanting a hoodie
• Reduced spontaneous movement/energy outside training (less “life energy”)

Iron deficiency and other nutrition-related problems are commonly discussed in the Relative Energy Deficiency in Sport literature and may appear alongside low energy availability depending on diet quality and load.

Relative Energy Deficiency in Sport can occur in any sport, but risk rises when performance or selection pressures reward leanness, weight targets, or extremely high training volumes.

Higher-risk contexts include:

• Endurance sports (distance running, cycling, triathlon, rowing)
• Weight-category sports (wrestling, boxing, mixed martial arts, lightweight rowing)
• Aesthetic or judged sports (gymnastics, diving)
• Sports with “lean = faster” culture (climbing, cross-country skiing)
• Military, tactical, or high-volume training programs
• Athletes returning from injury who try to “get back in shape” rapidly

Male endurance athletes, in particular, are frequently highlighted in reviews of low energy availability due to high training energy expenditure paired with inadequate intake.

You are not diagnosing. You are pattern-recognizing—and creating a safe pathway for evaluation.

Instead of “Are you under-eating?” try:

• “How’s your sleep been—any early waking or restless nights?”
• “Any changes in mood, motivation, or stress tolerance?”
• “How’s your recovery between sessions compared to last month?”
• “Any recurring pain, especially shin/foot/hip pain that ramps with impact?”
• “Has your appetite changed since training increased?”
• “Any unplanned weight changes?”
• “Do you feel you’re fueling enough to support this training block?”

Relative Energy Deficiency in Sport is influenced by culture: weigh-ins, public body composition talk, social media, and “clean eating” competitions.

The International Olympic Committee emphasizes prevention principles and safer practices around body composition assessment to reduce risk and harm.

If you suspect Relative Energy Deficiency in Sport, the goal is not to panic—it’s to interrupt the trend early.

• Reduce training load temporarily (especially high-impact volume and high-intensity density).
• Add recovery days that are truly recovery (not secret extra sessions).
• Remove any weigh-ins or body composition goals until health stabilizes.

These are not “diet plans.” They are performance safety measures.

• Ensure a real pre-training meal or substantial snack is non-negotiable.
• Add post-training recovery calories quickly after sessions.
• Increase carbohydrates around demanding workouts.
• Add an extra daily snack even if appetite is low (liquid calories can help).
• Watch for athletes who train early and “save calories” until noon.

The International Olympic Committee has developed clinical guidance tools for evaluating suspected Relative Energy Deficiency in Sport and stratifying risk, including training and competition recommendations for clinicians.

A typical sports medicine evaluation may consider:

• Detailed training history and nutrition patterns
• Injury history (especially bone stress injuries)
• Psychological factors (food rigidity, compulsive training)
• Lab markers and clinical signs (as appropriate)
• Bone health assessment when indicated

Coach’s role: support the athlete’s dignity, reduce performance pressure, and coordinate a safe return-to-performance pathway.

Recovery is not just “eat more for a week.” Because the body has adapted to scarcity, it may take time to normalize hormones, bone remodeling balance, and consistent recovery.

Common milestones you may see:

• Sleep improves first (fewer early wake-ups, deeper rest)
• Mood stabilizes and irritability drops
• Training feels “easier” at the same pace/power
• Injuries stop cycling and begin to truly heal
• Strength begins progressing again with less effort

If bone stress injury risk is involved, return-to-running or return-to-impact should be conservative and medically guided, particularly when low energy availability may have contributed. Evidence in male athletes continues to link low energy availability-related patterns with bone stress injury risk.

You prevent this condition mostly by changing systems, not by lecturing individuals.

• Put “fueling targets” next to workout targets.
• Normalize carbohydrate and recovery nutrition as performance tools.
• Build travel fueling plans (airports, buses, tournament days).
• Teach athletes that appetite can lag behind expenditure.

• No public weigh-ins.
• No jokes about fat, dieting, or “earning food.”
• No praise that equates leanness with worth.
• If body composition is medically or performance relevant, follow athlete-centered, consent-based best practices consistent with International Olympic Committee guidance.

Many cases emerge when training ramps but life stress also ramps:

• exams, travel, relationship stress
• job pressure
• poor sleep opportunity
• injury return

When recovery capacity drops, energy availability often drops too—especially in athletes who respond to stress by training more.

Make sure assistant coaches and strength staff know that for men, early flags often include:

• sleep disruption
• mood flattening or irritability
• libido changes
• recurring injuries, especially bone stress injuries

Overtraining and under-fueling often overlap. But here is the key difference:

• If you reduce load and the athlete still can’t recover, or if injuries keep recurring, you must ask: Is the athlete adequately fueled for adaptation?
• Relative Energy Deficiency in Sport is fundamentally about insufficient energy availability driving multi-system impairment, as emphasized by the International Olympic Committee consensus.

In practice, many athletes are not “overtrained” in isolation—they are under-fueled for the training they are doing.

Encourage prompt medical evaluation when you see:

• Suspected stress fracture or bone stress injury symptoms (localized pain that worsens with impact)
• Rapid weight loss, dizziness, fainting, chest symptoms
• Severe mood changes, depression, or anxiety
• Signs of disordered eating or compulsive exercise
• An athlete who cannot rest without panic or guilt

• Relative Energy Deficiency in Sport in men is common enough to deserve routine awareness, especially in endurance, weight-category, and leanness-focused sports.
• The earliest signs are often sleep disruption, mood changes, libido decline, and recurrent injuries, not dramatic weight loss.
• You don’t need to diagnose; you need to notice patterns, reduce harm, and refer appropriately using sports medicine pathways informed by established clinical tools.
• Prevention is cultural: athlete-centered body composition practices, fueling as part of training, and recovery-respecting programming.