After 12 hours of racing, the question of sleep already starts to arise. And the longer the effort continues – 24, 48, 72 hours or more – the more central it becomes.
Fatigue doesn’t only come from your legs. It hits when your brain gets foggy, your eyes close against your will, and every step becomes a battle.
And just like with your legs, not all runners are equal when it comes to sleep. Some fall asleep before even 24 hours of effort. Others hold on until hallucinations. And then there are those extreme-format runners, like the Backyard, capable of going up to 119 hours (five days!) with only a few micro-naps of a few minutes.
What impact does sleep have on performance?
Sleep deprivation acts like intoxication. After more than 24 hours awake, your alertness drops as much as if you had drunk several glasses of alcohol. Result: loss of clarity, slower reflexes, navigation mistakes. On a technical descent, that can mean a fall. At night, missing a marker.
There are also hallucinations, well known to ultra-runners. When your brain invents to compensate, it blurs your perception: terrain changes shape, shadows become silhouettes, and every landmark becomes uncertain.
And of course, sleeping means stopping – it costs you time and places.
To sleep or not is not just a matter of comfort. It’s a factor to include in your strategy, just like your nutrition or hydration.
How to manage fatigue in long-distance races?
Depending on the distance, you can choose different strategies to manage fatigue during your ultra:
- Micro-naps (5 to 20 minutes): on the side of the trail, at a life base, sometimes even with your head resting on your pack, a micro-nap gives a real “reset” effect to the brain: even 5 minutes help to regain energy.
💡 Tip: set an alarm (watch or phone) to fully let go without fearing you won’t wake up.
- Long naps (30 to 60 minutes): best for races where you’ll spend at least 2 nights outside (Tor des Géants, Barkley, Grand Raid).
💡 Tip: prefer life bases, quiet, with mattress, blanket, and possibly earplugs to escape noise. If you sleep on the trail, move aside to avoid being disturbed.
- Real sleep: in races lasting 3 days or more, taking true sleep blocks of 3 to 5 hours can be a winning strategy. Some runners manage without, but for most, better to sleep a few hours than to drag all day half-asleep at 3 km/h.
💡 Tip: prioritize night sleep. In races, you generally move slower in the dark, so you lose less time by sleeping then. In specific contexts like the desert, do the opposite: run at night in the cool, and sleep during the day when it’s scorching.
How to prepare for fatigue beforehand?
There is no miracle solution to sleep. But if you’re preparing for an ultra-trail, anticipating fatigue already stacks the odds in your favor to reach the finish line.
Build a “sleep capital”
The nights before an ultra are crucial. You can’t stockpile days of sleep, but sleeping more 2 to 3 nights before the race helps reduce your deficit at the start. On the other hand, going to bed late or sleeping poorly the night before can cost you dearly from the very first night outside.
Train to run tired
Add sessions early in the morning or late at night to get your body and mind used to night effort. In the months before the race, you can also enter races with night starts or late finishes: a good way to adapt to nighttime race conditions.
Plan your strategy ahead
Just like your fueling, plan when and where you might sleep (life base, refuge, or simply a 10-minute quiet break). A plan can adapt and change, but better a plan than nothing at all.
At least this way, you’ve thought about it based on your abilities: knowing if you’ll allow yourself micro-naps or long sleep blocks. The “where” and “when” will then be decided on the ground.
Equip yourself smartly
Sleep in ultras goes hand in hand with minimal comfort:
- A reliable headlamp to avoid mistakes at night,
- An appropriate jacket so you don’t freeze if you stop a few minutes,
- A lightweight mattress for more comfort at life bases,
- A 2-in-1 sleeping bag for cold nights,
- Safety gear to manage a break safely in tough moments.
Conclusion
In ultra-trail, fatigue and sleep are part of the race. It’s something to manage like your fueling or gear. The real question is not “to sleep or not?” but to anticipate fatigue with a strategy, tested in training, and adapt to stay clear-headed until the finish line.
