How Much to Sleep, by Format
These are our planning defaults. No sleep protocol has been tested in races, so sleep sooner and longer whenever you start weaving or nodding off. Arrange a permitted rest location and a helper before the race, and leave room to extend or move sleep stops. Martin and colleagues surveyed 636 ultramarathon runners; in 221 race reports, more in-race sleep went with slower finishes in races of 36–60 hours (r = 0.48) and over 60 hours (r = 0.44). These associations do not show that reducing sleep improves performance: slower runners also spend longer on the course.
| Format | Our default | How to take it |
|---|---|---|
| 24-hour | No planned sleep | A 10–20 minute nap in a warm place if you get drowsy; hallucinations or confusion mean stop and get assessed |
| 48-hour | 1–3 hours in total | A 20-minute nap on night one if drowsy; one block of about 90 minutes in the small hours of night two, plus 20-minute naps as needed |
| Six-day | 2–4 hours a night, from night one | One or two blocks of about 90 minutes between midnight and 05:00, plus 20-minute daytime naps if you nod off; sleep longer if that leaves you unsafe |
| Backyard ultra | Only within the interval before the next start | Run 50-minute yards to leave about 10 minutes; from the second night, 5–10 minute naps in that gap when sleepiness hits, earlier if needed; crew handles wake-up |
| 200-mile | 4–8 hours in total for a first race | 20-minute or roughly 90-minute sleeps at permitted aid-station rest areas, the longer ones on nights two and three |
Sleep before you have to. Plan the long sleep for the small hours, when the body clock is lowest and walking pace drops anyway, and take it before sleepiness forces the stop. In a six-day race, sleep from the first night: staying awake for 36 hours to bank distance leaves a debt that every following night has to repay.
If you have a sleep disorder, a heart or neurological condition, or take medication that affects alertness, talk to your doctor before you plan any sleep restriction.
Plan Naps and Allow Time to Wake
Brooks and Lack gave 24 healthy young adults, after a night restricted to about 5 hours, naps of 5, 10, 20 or 30 minutes; the 30-minute nap caused a spell of impaired alertness on waking. The 10-minute nap produced immediate benefits; improvements after 20 minutes emerged later, and the 30-minute nap brought grogginess first. The study did not test 90-minute sleeps or racing. A sleep cycle runs roughly 90 minutes, so a block of that length often ends in lighter sleep, though cycles vary. Our defaults follow from that:
- Short nap: set the alarm for 25 minutes from lying down, which gives about 20 minutes asleep if you drop off quickly.
- Long sleep: set it for 95–100 minutes, which allows for falling asleep and about one cycle. Avoid 30–60 minute naps, the length most likely to end in deep sleep and a slow restart.
- Before lying down: dry top, warm layer, shoes off, feet checked, food ready for waking.
- On waking: sit for two minutes, eat something, then stand and walk 50 m with the crew watching. Restart only if speech, balance and orientation are normal.
- After the race: someone else drives.
Do not take sleeping tablets during a race. They extend grogginess after waking and can interact with exertion and dehydration.
A Worked Sleep-Operations Sheet
This example is for a 48-hour loop race with a two-person crew.
| Field | Completed example | Fill in your plan |
|---|---|---|
| Place | Organizer-permitted crew tent beside base; confirm access before the start. | Permitted location and backup: ______ |
| Planned sleeps | Rest options on both nights. Example longer stop: 02:00 on night two, brought forward or extended if needed. Neurological warning signs trigger medical assessment. | Planned sleeps and trigger for a nap: ______ |
| Responsible person | Alex handles the stop; Sam takes over only after an explicit handoff. | Primary and backup helper: ______ |
| Before rest | Log arrival, set the alarm (25 or 100 minutes), prepare dry layers and warm food. | Alarm length and supplies: ______ |
| Wake-up check | Helper stays while the runner sits, eats, stands and walks 50 m. No restart until speech and balance are normal. | Who checks and records the decision: ______ |
| Unexpected change | A closed tent means using the backup; a warning sign means stopping and contacting race medical staff. | Backup place and medical contact: ______ |
| Crew handoff | Write actual sleep times and caffeine already taken, with product and milligrams. | Log location and next helper: ______ |
| After the race | Sam drives; arrange another driver if Sam is also too tired. | Driver and backup transport: ______ |
Download the blank sleep-operations worksheet to complete and print. Add locations and arrival windows to the crew and drop-bag planner, and rehearse finding the rest area while alert.
Kishi and colleagues ran a cross-sectional survey of 1,154 finishers of two mountain ultramarathons, one of 111 km and one of 165 km. It describes what runners did; the short-nap evidence comes from laboratory research, and the longer rest blocks are planning examples rather than tested prescriptions.
Caffeine: How Much and When
The ISSN position stand finds 3–6 mg/kg effective and reports frequent side effects at about 9 mg/kg. For ultras it recommends holding caffeine back for the later stages and using small repeat doses. Our defaults, also used in the 24-hour nutrition guide:
- First 10 hours: none, so it still works at night.
- Overnight: about 50 mg per hour, or one 1–2 mg/kg dose (70–140 mg at 70 kg) every two hours.
- Before a planned sleep: nothing in the three hours beforehand, and stop earlier after large doses. Drake and colleagues found sleep disruption after 400 mg even six hours before bed.
- Multiday races: the same overnight dose each night, with no daytime caffeine; cut back if you notice jitters, palpitations or worse sleep.
Count coffee, cola, gels and tablets in the total, and use only products you have tested in training. Skip caffeine if it causes palpitations, tremor or worse nausea, and check with your doctor first if you are pregnant, have a heart condition or take interacting medication.
When Sleepiness Means Stop
Falling asleep while moving, hallucinations, confusion, repeated falls or loss of coordination mean stop in a safe place and get race medical staff. Do not treat these as ordinary tiredness without an assessment: low blood sodium, heat illness, hypothermia and low blood sugar can look the same. Crew should not wait to see whether a nap or caffeine fixes them. The full list is in the medical red flags.
Sources
- Martin, T. et al. (2018). Sleep habits and strategies of ultramarathon runners. PLOS ONE, 13(5), e0194705.
- Brooks, A. & Lack, L. (2006). A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative?. Sleep, 29(6), 831–840.
- Kishi, A. et al. (2024). Sleep and Ultramarathon: Exploring Patterns, Strategies, and Repercussions of 1,154 Mountain Ultramarathons Finishers. Sports Medicine - Open, 10(1), 34.
- Benchetrit, S. et al. (2024). Sleep deprivation, extreme exertion, and cognition at a backyard ultra. PLOS ONE.
- Hurdiel, R. et al. (2015). Sleep deprivation, strenuous exercise, and cognitive performance at UTMB. Journal of Sports Sciences.
- Drake, C. et al. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine, 9(11), 1195–1200.
- Tiller, N.B. et al. (2019). International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing. Journal of the International Society of Sports Nutrition, 16(1), 50.
- Guest, N.S. et al. (2021). ISSN position stand on caffeine and exercise performance. Journal of the International Society of Sports Nutrition.
Frequently Asked Questions
When should you stop caffeine before a planned sleep?
Our default is at least three hours before a short race sleep, and longer after big doses: a small controlled study found that 400 mg of caffeine disrupted sleep even six hours before bedtime. Count every source, and if you are sensitive to caffeine, stop earlier still.
How much should you sleep in a 48-hour race?
Our default is 1–3 hours in total: a 20-minute nap on night one if you get drowsy, and one longer block of about 90 minutes in the small hours of night two. Sleep sooner and longer if you start weaving. Surveys associate longer sleep with slower finishes, but that does not show sleeping less makes you faster; slower runners are simply out longer.
Can caffeine replace sleep?
No. Caffeine improves alertness for a few hours but does not repay sleep debt. If you are falling asleep while moving, stop and nap or get assessed; do not take another dose and keep going.