Sleep for Runners

The nights that matter most

Protect the night before a hard workout and before a long run, and the week before your race. A short night makes the same session cost more and deliver less. In a 2022 review of 69 studies, performance was 7.6% lower after sleep loss (6 hours or less in 24) than after normal sleep, and the loss showed up in every kind of exercise, endurance included. Most participants were men and few were runners, and the studies varied widely, so treat the size as rough. The harm was consistent after a night with no sleep or after waking earlier than normal, and not after a later bedtime alone¹.

In 10 recreational male runners, a night with a 3-hour sleep window slowed a 10 km treadmill time trial the next morning by 5% compared with an 8-hour window (51.9 against 49.4 minutes), and caffeine before the run offset the loss². If the choice is an early alarm for a run or the sleep, take the sleep and run later.

After a short night

Keep the day's run easy and move the hard session to the next day, because performance falls after a short night. If a short night is part of your week, such as after a late shift, put an easy run with strides there and the hard session after a full night.

Do not judge your fitness from a workout after a short night. A slow session then says more about the night than about the training.

Over a training block

Poor sleep over weeks is a reason to back off before you get sick or hurt. When a run you used to handle stops feeling manageable, coaches check sleep and food before they blame fitness. In a 2015 study of 164 healthy adults who were given a cold virus after a week of tracked sleep, those who slept under 5 hours or 5 to 6 hours a night were about four times as likely to develop a cold as those who slept more than 7 hours, although the range of estimates was wide. Sleeping 6 to 7 hours carried no clear extra risk³.

For injury, the evidence is mixed. Over 26 weeks in 339 adult runners, lower self-reported sleep quality went with a higher risk of running-related injury, about 1.4 times as high⁴. In 161 high school cross-country runners, week-to-week changes in sleep were not associated with injury⁵. Both studies are observational, so neither shows that improving sleep prevents injury. If poor nights are piling up, trim a hard session before pain appears.

How much sleep you need is individual. A 2021 expert consensus statement describes habitual short sleep in elite athletes as under 7 hours a night and says a single figure for everyone, such as 7 to 9 hours, is unlikely to be ideal. It recommends going by how much sleep you perceive you need⁶. If you wake unrefreshed on 7 hours, aim for more.

Before a race

Protect your sleep for the week before the race, and add some if it comes easily. Whether extra sleep makes you faster is not settled. A 2026 review of 16 studies of ultra-endurance athletes linked extended sleep the night before a race to better physical performance⁷. Among 1,154 finishers of two mountain ultramarathons, those who reported sleeping more in the week before did not finish faster⁸. Both are observational, so neither shows cause, and going in rested costs you nothing either way.

The last night is the one you often cannot control. Coaches who send runners to destination races find that one short night does not usually hurt and that two or three can, and that worrying about sleep or taking something to force it can cost more than the lost hours. For sleep and naps during an ultra, see night running.

Evening habits

Caffeine and alcohol are the two habits with measured costs. In a 2023 analysis of 24 studies, caffeine cut total sleep time by 45 minutes and sleep efficiency by 7%. To avoid losing sleep time, the authors suggested finishing a coffee (107 mg per 250 mL) at least 8.8 hours before bed and a standard pre-workout serve (217.5 mg) at least 13.2 hours before bed⁹. For a 10 pm bedtime, that puts the last coffee before about 1 pm.

Alcohol shortens the time to fall asleep only at high doses, and it delays and shortens REM sleep from a low dose of about two standard drinks, more so at higher doses¹⁰. Leave alcohol out of the nights before hard sessions and the race.