Deep, slow-wave sleep — the stage where muscle repair and growth hormone release peak — naturally declines with age, often dropping by half between your 30s and 60s. For anyone training regularly, that decline directly limits how well the body recovers and adapts.

The good news is that sleep quality, unlike sleep stage biology, is highly responsive to habits. A few consistent changes can meaningfully restore deep sleep time.

The recovery basics
Consistent sleep and wake times, a cool dark room, and no hard training within 2 hours of bed are the three habits with the strongest evidence behind them.

1. Fix your wake time

Same time, 7 days a week

Pick a wake-up time you can hold every day, including weekends, and get outside for natural light within 30 minutes of waking.

Why it works: A consistent wake time anchors your body clock, which drives when deep sleep occurs each night.

2. Cool, dark, quiet room

Bedroom around 18°C / 65°F

Lower the thermostat in the evening, block outside light, and consider earplugs or a white-noise machine if noise is an issue.

Why it works: A slight drop in core body temperature is one of the body's triggers for entering deep sleep.

3. Wind-down routine

30–60 minutes before bed

Dim the lights, put screens away, and do something calm — reading, stretching, or a warm shower.

Why it works: Bright light and stimulating screens in the evening suppress melatonin, delaying and shortening deep sleep.

Make it stick

Track your sleep and how you feel for two weeks after making one change at a time — it's easier to see what's actually helping.

If you train hard, treat your wind-down routine with the same seriousness as your workout plan; one enables the other.

A note on safety
Persistent insomnia, loud snoring, or daytime sleepiness despite enough time in bed can signal a sleep disorder — worth discussing with your doctor.