How much sleep for muscle growth?

// What the research shows

There is no sleep recommendation specifically for muscle growthHypertrophy (muscle growth) A muscle getting bigger, mainly through thicker muscle fibres. More in the glossary →. The best guide are the age-based recommendations of the National Sleep Foundation (Hirshkowitz et al., 2015), later reaffirmed after a review of 133 meta-analysesMeta-analysis A study of studies: the results of many individual studies are pooled statistically. More in the glossary →: 8 to 10 hours for 14- to 17-year-olds, 7 to 9 hours for 18- to 64-year-olds, 7 to 8 hours from 65. That too little sleep harms muscle is shown by small, well-controlled studies. One night without sleep lowered muscle protein synthesisMuscle protein synthesis (MPS) The building of new muscle proteins. Training and protein raise it for several hours. More in the glossary → by 18% (Lamon et al., 2021). Five nights with only 4 hours in bed lowered it too, but hard interval training offset this (Saner et al., 2020). On a diet with 5.5 instead of 8.5 hours of sleep opportunity, participants lost clearly more fat-free massLean mass / fat-free mass Everything in the body except fat: muscle, bone, organs and water. More in the glossary → and less fat (Nedeltcheva et al., 2010). An expert panel for elite sport advises against a fixed rule for everyone and recommends finding individual needs (Walsh et al., 2021).

// In practice

• Plan 7 to 9 hours in bed, 8 to 10 as a teenager. Time in bed isn't time asleep, so a small buffer helps.
• Especially when dieting, don't cut sleep: it helps decide whether you lose fat or muscle.
• If you're constantly tired despite enough time in bed, snore loudly or stop breathing at night: get it checked by a doctor.

// Limitations & open questions

The studies are small (10 to 24 people), short and mostly in young adults. Long-term studies directly measuring how much muscle you build over months on 6 vs. 8 hours of sleep are missing. The age recommendations concern health in general, not muscle growth specifically.

// Sources

• Konsens 2015Hirshkowitz et al. – National Sleep Foundation's updated sleep duration recommendations (Sleep Health) ↗cite
• Einzelstudie 2021Lamon et al. – Acute sleep deprivation, muscle protein synthesis and the hormonal environment (Physiological Reports) ↗cite
• Einzelstudie 2020Saner et al. – Sleep restriction, with or without high-intensity interval exercise, and myofibrillar protein synthesis (J Physiol) ↗cite
• Einzelstudie 2010Nedeltcheva et al. – Insufficient sleep undermines dietary efforts to reduce adiposity (Ann Intern Med) ↗cite
• Positionspapier 2021Walsh et al. – Sleep and the athlete: narrative review and 2021 expert consensus recommendations (Br J Sports Med) ↗cite

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