What Sleep Deprivation Actually Does to Athletes

One short night

A single night under 6 hours raises perceived effort, drops time-to-exhaustion, and impairs decision-making. Strength and short-burst power often hold up — endurance and pacing fall apart first.

A week of restriction

Two studies of athletes restricted to 5-6 hours for a week show: 11% drop in glucose tolerance, 30% drop in growth hormone release, elevated cortisol, and slower reaction time. Training adaptations stall even though workouts get completed.

Chronic short sleep (months)

Runners who chronically sleep under 7 hours show:

• 1.7x increased injury risk in adolescent athletes
• Higher resting heart rate and lower HRV
• More frequent upper respiratory infections
• Symptoms that mimic overtraining (heavy legs, mood drop, plateau)

The fix isn't complicated

Move bedtime 30 minutes earlier and protect it like a workout. Most runners don't need a new gadget — they need to stop checking their phone after 10pm.

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