Skip to content
RecoveryDIAGNOSIS

TRAINING RUINING YOUR SLEEP? HERE'S WHY

You train hard, eat well, go to bed tired — then lie there wired. Resting HR elevated. Waking at 3am. The harder you train, the worse you sleep.

THE SHORT ANSWER

Most often, this is because late-evening high-intensity sessions elevate cortisol for 2-4 hours. The fix: time hard sessions — finish intervals 3+ hours before bed.

WHY THIS HAPPENS

Late-evening high-intensity sessions elevate cortisol for 2-4 hours

Sympathetic nervous system dominance from chronic high training load

Under-fuelling — low glycogen and elevated cortisol disrupt sleep

Overtraining spectrum — disrupted sleep is an early overtraining signal

Caffeine too late — half-life of 5-6 hours means 2pm coffee affects midnight sleep

Screen exposure post-ride compounding sympathetic arousal

EXPERT EVIDENCE

WHAT THE EXPERTS SAY

Andy GalpinProfessor of Kinesiology, Cal State Fullerton; muscle physiologist

Galpin treats sleep as a primary training variable, not an afterthought — it's where adaptation and nervous-system recovery actually happen. Late, intense sessions and chronic high load keep the sympathetic system switched on, so the fix is finishing hard efforts well before bed, fuelling enough to keep cortisol down, and deloading when sleep and HRV both slide.

Hear it: The Science Of Getting Faster After 40 | Dr Andy Galpin