Sleep
Deep sleep is the stage people worry about most and control least. The good news is that the levers that raise it are few, and they are the same ones that fix everything else.
Most adults get 60 to 100 minutes of deep sleep per night — roughly 13 to 23 per cent of total sleep. There is no single correct figure, and the amount falls naturally with age at around 1.7 per cent per decade. The most reliable way to get more is to sleep longer overall, because deep sleep is taken in the first half of the night.
| Total sleep | Typical deep sleep |
|---|---|
| 6 hours | 45–80 minutes |
| 7 hours | 55–95 minutes |
| 8 hours | 60–110 minutes |
| 9 hours | 70–120 minutes |
The percentage stays roughly constant, so the single most effective way to increase deep sleep in minutes is to increase total sleep. Chasing deep sleep directly, while sleeping six hours, is the wrong order of operations.
Deep sleep declines steadily through adult life, at roughly 1.7 per cent per decade. A 25-year-old and a 55-year-old with identical habits will not see identical numbers, and the older one is not doing anything wrong. If you have been tracking for years and the trend is gently down, that is biology rather than a problem to solve.
This is the stage most associated with physical restoration: tissue repair, immune function and growth hormone release. It is why deep sleep matters disproportionately to anyone training hard. Two nights of poor deep sleep will not undo a training block, but a sustained shortfall alongside heavy training is the classic recipe for stalled progress and a resting heart rate that keeps creeping up.
Less than you would like. Wrist and ring devices infer sleep stages from movement and heart rate rather than measuring brain activity, and agreement with clinical polysomnography is moderate at best for stage estimates. Total sleep time is measured far more reliably than the split between stages.
The practical consequence: treat the weekly trend in deep sleep as a signal, and treat a single night’s figure as noise. If the trend drops for two weeks while your training load rises, that is worth acting on. If Tuesday was 40 minutes and Wednesday was 90, that is mostly the algorithm.
Most adults get 60 to 100 minutes, which is about 13 to 23 per cent of total sleep. There is no single correct number and it varies with age, training load and genetics. If you wake feeling restored and your resting heart rate is stable, you are almost certainly getting enough.
For most adults, yes. One hour sits inside the normal range for a seven to eight hour night. It only becomes a concern if it is paired with persistent daytime fatigue, a rising resting heart rate or a total sleep time well under seven hours.
The usual causes are too little total sleep, alcohol, training late in the evening, a steep calorie deficit, an irregular bedtime or a warm bedroom. Age matters too: deep sleep falls by roughly 1.7 per cent per decade, so a gentle long-term decline is normal.
Sleep longer overall, since deep sleep is a fairly fixed percentage of total sleep. Then keep a fixed wake time, move hard training earlier in the day, avoid alcohol near bedtime, eat enough if you are dieting, and keep the room cool and dark.
Only roughly. Consumer devices infer stages from movement and heart rate rather than measuring brain activity, so stage estimates are much less reliable than total sleep time. Use the weekly trend rather than any single night.
Deep sleep almost never falls for a mysterious reason. It falls because of a late session, a heavy week, a night out or a deficit that is too steep. NutriMacro keeps your sleep next to the training you logged and the food you ate, so the cause is on the same screen as the symptom instead of in a separate app.
NutriMacro is a nutrition and training tracker for iPhone and Android. It logs food by barcode, photo or search, counts food in slices and units rather than grams, and keeps strength training, GPS activities, sleep and recovery in the same daily view. It runs in the language of your phone across 108 countries.
Read next: How much REM sleep do you need? What is a good sleep score? Low sleep score after 8 hours?
