Sleep — The Most Underrated Training Tool

Why it matters so much

Training is the stimulus; adaptation happens during recovery — and a large share of that recovery happens while you sleep. Sleep is when the body does much of its tissue repair and hormonal restoration, so cutting it short directly degrades how well you absorb training¹. For a runner, sleep isn't time away from training — it's part of training.

What too little does

Short or poor sleep measurably hurts the things runners care about: reaction time, endurance, perceived effort (everything feels harder), mood, and immune function¹. Chronically under-slept runners tend to feel flat, recover slowly, and pick up more illnesses and nagging aches — the same picture as under-recovery from any cause.

How much you need

Most adults need 7–9 hours, and hard-training runners sit at the upper end of that range because they have more to repair. Consistency matters as much as duration — a regular sleep and wake time stabilizes your body clock and improves sleep quality. If you're ramping training, protect sleep first, not last.

Practical habits

Simple, well-supported sleep hygiene moves the needle¹:

• Keep a consistent bed and wake time, even on weekends.
• Wind down without bright screens for 30–60 minutes before bed; keep the room cool and dark.
• Be careful with late caffeine and alcohol — both fragment sleep, even when they don't stop you falling asleep.
• On heavy-training or pre-race blocks, bank extra sleep ("sleep extension") rather than cutting it for an early run.