Sleep and Endurance Races

Inspired by the ultras on offer in The Running Awards Endurance category, I started training for an ultra myself. It’s my first race that will take more than a day, with a cut-off time of 60 hours. When I tell people this, their eyes boggle. “What about sleep?” they ask. Well, first they ask, “Are you insane?” but sleep is usually the second question. Being the running nerd that I am, I’ve delved into some of the research to find out what other runners do...

How much sleep do runners get during ultra endurance races?

One study looked at the infamous North Face® Ultra Trail du Mont Blanc® (UTMB®)(1). The race is 168km long with 9,600m gained altitude. That’s more than 9 times up Mt Snowdon! The 24 racers studied took between 27 to 44 hours to finish the race, which started at 4.30pm.

9 runners didn’t sleep at all over the entire race. The remaining 15 runners took 1 or 2 naps, lasting just 4 to 22 minutes long. Almost everyone who took more than 36 hours to finish had a sleep at some point and the study found—not surprisingly!—that sleeping was associated with a longer race, or looking at it the other way around, a longer race was associated with sleeping. There’s no way of knowing from this study if that’s because you need to sleep if you’re out for that long or if the slower runners were struggling for other reasons and used sleep as part of their recovery strategy.

(It would be really interesting to do this study again but add in a questionnaire at the start asking runners whether or not they plan to sleep. If anyone feels like giving me a paid holiday to Chamonix to conduct said study, please feel free to send me a small bag of gold and a note to my boss explaining where I’ll be next August…)

What’s the best way to prepare for these events?

There’s nowhere near enough research out there to answer this question, but another UTMB study dropped a few tantalising hints(2). They asked 303 finishers to fill in a questionnaire about their preparation for sleep deprivation, how much sleep they thought they had during the race, and their race finish time. They found…

  • Getting extra sleep the night before helped significantly (just have to hope race nerves don’t keep you awake, of course)
  • Having extra naps the day before didn’t help
  • Deliberately doing training runs sleep-deprived, so you’re used to the experience, doesn’t seem to help (this was good news to me: an excuse not to do horrible sleep-deprived training runs!)

What’s the effect of all that missed sleep?

Surprisingly, only 8 runners in the first study said they had symptoms of sleep deprivation. That said, some of those symptoms were pretty severe- 4 had visual hallucinations, 5 had trouble keeping their eyes open while running, 3 had trouble with their balance, and 1 had an hour of “transient amnesia”, unable to remember the last section of the race that he’d done.

Unsurprisingly, tests showed the runners’ reaction time slowed and they made more errors in a simple response time test after the race than before. This was no better in the runners who’d slept than those who hadn’t, which makes sense considering those naps were just 4 to 22 minutes long.

My conclusions from this research:

  • Plan ahead as you will be tired. An extra night’s accommodation, or a co-driver after the event is important.
  • Try to get extra sleep in the run-up (pun intended) to multi-day races
  • Sadly, naps probably aren’t helpful (but you don’t have to tell your family that if you still want an excuse)
  • Give the sleep-deprived training runs a miss
  • After an ultra is not a good time to play Whack-a-Mole
  • The answer to everyone’s first question for me was probably yes



(1) Hurdiel R, Pezé T, Daugherty J, Girard J, Poussel M, Poletti L, Basset P, Theunynck D. Combined effects of sleep deprivation and strenuous exercise on cognitive performances during The North Face® Ultra Trail du Mont Blanc®(UTMB®). Journal of sports sciences. 2015 Apr 21;33(7):670-4.

(2) Poussel M, Laroppe J, Hurdiel R, Girard J, Poletti L, Thil C, Didelot A, Chenuel B. Sleep Management Strategy and Performance in an Extreme Mountain Ultra-marathon. Research in Sports Medicine. 2015 Jul 3;23(3):330-6.

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