Sleep Is a Safety Tool
Sleep strategy is not a toughness contest or a guaranteed performance formula. Ultra-endurance field studies show substantial variation in sleep behavior and report cognitive and motor problems with prolonged wakefulness and exertion. A plan should reduce exposure to preventable harm while respecting the course, race rules, and individual runner.
Keep routine rest planning separate from medical escalation. Read the warning signs below with your crew before the start; they override every planned restart or performance goal.
Plan for the Event
Event format changes the available sleep locations and the consequences of impairment, but it does not create a universal protocol. Use the table as a planning checklist rather than a recommendation to stay awake or nap for a particular duration.
| Format | Questions to resolve before the start | Safety concern to plan around |
|---|---|---|
| 24-hour | Where can you stop safely, who can observe you, and how will medical staff be reached? | Assuming the shorter format makes prolonged wakefulness safe |
| 48-hour | What sleep opportunities fit your history, and who can trigger an earlier stop or assessment? | Waiting until cognition or balance is already impaired |
| Six-day | How will repeated sleep opportunities, warmth, noise, crew handoffs, and recovery be managed? | Accumulating sleep debt across several days without reassessment |
| Backyard ultra | What do the rules allow, where is a supervised rest area, and what signs end participation? | Attempting another loop despite involuntary sleep or unsafe coordination |
| 200-mile | Where are safe sleep and extraction points, and which technical or traffic sections require full alertness? | Continuing alone on consequential terrain while impaired |
A runner preparing for a 48-hour race needs a plan built for that event rather than one copied from a backyard or six-day race. Observational averages describe what runners did, not what any individual should do.
Build an Individual Sleep Plan
Write the plan while rested with the runner, crew, and qualified coach. Race medical staff may not be able to pre-approve a personal plan, so know the event's rules, locations, and escalation procedures before the start.
- Identify permitted, warm, and physically safe sleep locations.
- Define ordinary planned sleep opportunities from the runner's history instead of a fixed online schedule.
- Assign crew members to observe alertness, speech, orientation, balance, and coordination.
- Write warning signs that trigger an immediate stop and medical assessment.
- Plan how the runner will wake fully, orient, stand, and demonstrate safe coordination before any restart.
- Arrange post-race transport so a sleep-deprived runner does not drive.
Do not force shoes on, begin walking, or leave an aid station before the runner feels and appears ready. If alertness, orientation, balance, or coordination is not normal—or medical staff advise against continuing—do not restart. Sedating sleep medication should not be improvised during a race; discuss any medication with the prescribing clinician and check event rules in advance.
A Worked Sleep-Operations Sheet
Use this hypothetical loop-race example to divide responsibilities. Agree the timing and duration of ordinary rest separately with your support team; this table does not set a sleep dose or authorize a restart.
| Field | Completed example | Fill in your plan |
|---|---|---|
| Place | Organizer-permitted crew tent beside base; confirm access before the start. | Permitted location and backup: ______ |
| Responsible person | Alex handles the stop; Sam takes over only after an explicit handoff. | Primary and backup helper: ______ |
| Before rest | Log arrival, agree the wake-up time, set the alarm, prepare dry layers. | Agreed wake time and supplies: ______ |
| Wake-up check | Helper stays present while the runner wakes, orients, stands, and checks normal movement. No automatic restart. | Who checks and records the decision: ______ |
| Unexpected change | A closed tent means using the pre-agreed backup; a warning sign means stopping and contacting race medical staff. | Backup place and medical contact: ______ |
| Crew handoff | Write actual sleep/stop times and any caffeine already taken, including product and amount. | 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. Rehearse finding the rest area and handing over the plan while alert.
What the evidence can tell us: 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. The study describes sleep behavior and reported problems; it does not establish the ideal nap timing or duration for a different runner, course, or format. The table above is an organizational example, not a protocol tested in that study.
Individualize Caffeine
Caffeine is optional. Its effects on alertness, performance, anxiety, heart rate, stomach tolerance, and later sleep vary between people. There is no universal timing or dose for an ultramarathon, and taking more does not correct the underlying sleep debt.
- Use only a product and amount already tolerated outside the race.
- Track total intake from coffee, gels, chews, drinks, tablets, and medications.
- Consider whether caffeine will interfere with the next planned sleep opportunity.
- Seek clinician or pharmacist guidance when health conditions, pregnancy, or medication interactions are relevant.
- Never use caffeine as a test before deciding whether a warning sign needs medical assessment.
Warning Signs
Stop in a safe place and contact race medical staff or emergency services immediately for confusion, hallucinations, involuntary sleep, repeated falls, loss of coordination, collapse, chest pain, severe breathing difficulty, seizure, severe or rapidly worsening headache, or behavior that is markedly unusual. Repeated vomiting, inability to keep fluids down, or inability to stay warm also warrants prompt assessment.
Do not label these symptoms as sleep deprivation without assessment. Hyponatremia, heat illness, hypothermia, hypoglycemia, medication effects, and other emergencies can overlap. Crew should not delay escalation to complete a checkpoint routine, feed the runner, administer caffeine, or wait for a nap to work.
For broader risk context, read Is multiday running safe? and the medical disclaimer.
Sources
- Martin, T. et al. (2018). Sleep habits and strategies of ultramarathon runners. PLOS ONE.
- 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.
- Guest, N.S. et al. (2021). ISSN position stand on caffeine and exercise performance. Journal of the International Society of Sports Nutrition.
- Hew-Butler, T. et al. (2015). International exercise-associated hyponatremia consensus statement. British Journal of Sports Medicine.
Frequently Asked Questions
Should you sleep in a 24-hour race?
There is no universal answer. Performance goals never override safety: stop in a safe place and contact race medical staff if involuntary sleep, confusion, hallucinations, falls, or loss of coordination appears. Plan ordinary sleep decisions around your history, course, support, and race rules with qualified guidance.
How much should you sleep in a 48-hour race?
Research describes wide variation and does not establish one safe or optimal duration. Create individual sleep opportunities with a qualified coach and support team, and seek clinical input for sleep disorders, health conditions, or medication that affects sleep or alertness.
Can caffeine replace sleep?
No. Caffeine may temporarily improve alertness for some people, but it does not reverse the underlying sleep debt or make unsafe movement safe. It should never delay stopping or medical assessment for a warning sign.