Sleep and recovery after workouts: why progress happens at night

A workout gives your muscles the signal, but they get stronger during recovery: on rest days and in your sleep. If you regularly sleep 5 hours, even a good plan will most likely work worse.

How much you need to sleep

In a joint 2015 consensus, the American Academy of Sleep Medicine and the Sleep Research Society recommend that adults aged 18-60 sleep 7 hours or more every night on a regular basis. Experts link regularly sleeping less than 7 hours with health risks, including weight gain and weaker immunity.

The consensus sets no strict upper limit. More than 9 hours may be normal for young people, for those who are ill or catching up after a long stretch of short sleep.

What sleep loss does to muscles

In a study by Lamon and colleagues (2021), 13 young men and women spent one night completely without sleep and, on another occasion, one night with normal sleep. After the sleepless night, muscle protein synthesis was 18% lower, blood cortisol 21% higher and testosterone 24% lower.

The study is small and looks at a full night without sleep. It says nothing about a habit of sleeping 6 hours. But the direction is clear: sleep is part of recovery, just like protein and rest between workouts. We cover protein in detail in the article on your daily protein target.

Signs you're not recovering

• Your results have stalled or dropped for several weeks in a row.
• Muscles stay sore for more than 3-4 days after a workout that's normal for you.
• You struggle to fall asleep even though you're tired, or you wake up feeling wrecked.
• Motivation is gone, and things you used to enjoy irritate you.
• Your morning resting heart rate is noticeably higher than usual for several days.

If this sounds like you, cut your training volume for a week and focus on sleep. If the symptoms don't pass, see a doctor: these signs also show up with problems unrelated to exercise.

7 habits for decent sleep

1. The same wake-up time. Even at weekends. A fixed wake-up time helps your internal clock keep its rhythm, and falling asleep in the evening gets easier.
2. A dark, cool bedroom. Blackout curtains or a sleep mask, air the room before bed.
3. Hard workouts end 2-3 hours before bed. Many people find it harder to fall asleep after late intervals. Light stretching in the evening is fine.
4. Caffeine before lunch. Coffee, strong tea and energy drinks in the afternoon push back sleep for many people.
5. Dinner not right before bed. A heavy meal just before sleep can keep you awake. A light snack is fine.
6. Screens away 30-60 minutes before. It isn't only the light: news feeds and messages keep your brain in active mode.
7. A calm ritual. A shower, stretching, a book, breathing. The same steps every evening become a "time to sleep" signal.

Rest between workouts

Recovery doesn't only happen at night. Leave at least a day between strength sessions for the same muscles. On rest days light activity helps: a walk, stretching, gentle yoga. Many people find it eases stiffness, and it doesn't get in the way of muscle recovery.

If you're just starting, the 20-minute circuit workout every other day with walks in between works well.

This article is general in nature and is not medical advice. If you have a chronic condition, an injury, are pregnant or feel pain during exercise, discuss the load with a doctor first. Learn more