Sleep Management Strategy and Performance in an Extreme Mountain Ultra-marathon A French group examined the running and sleep behavior of runners at the UTMB in 2013. 72% of the finishers did not go to sleep for 28% sleeppourers.Runners without sleeping pauses were faster in the finish as runners with sleeping breaks.It showed up the runner who had dealt with the strategy for the course before the run was much faster.
Who in the nights in front of an ultra more sleeps the race can complete faster. The very insightful analysis can be found under https://pubmed.ncbi.nlm.nih.gov/26020095/