New research published in the journal Medicine & Science in Sports & Exercise confirms what many athletes already know: a workout can feel terrible after a night with no or little sleep.
For the study, scientists recruited 12 male cyclists who performed a series of physical and mental tests once after a full night’s rest and again after an all-nighter. To make sure the participants didn’t sleep, they were observed by researchers from 11 p.m. to 7 a.m. The subjects were allowed to read, watch movies or listen to music, but could not do anything active, such as go for a jog.
Tests included perceived exertion after a 40-minute ride and cycling at an increasing intensity until fatigued. For the cognitive tests, participants were asked to press a button on a computer as quickly as possible when a particular color appeared on the screen. Participants repeated this test three times: the day before, as well as before and after, the cycling test. Finally, researchers measured each participant’s neuromuscular functions.
When subjects did not sleep, they became fatigued sooner on the bike and reported a higher rate of perceived exertion during their workout. The results support previous research on sleep deprivation's affect on athletic performance.
Surprisingly, neuromuscular function was similar between sleep-deprived and well-rested sessions, leading the researchers to conclude that fatigue of the central nervous system did not contribute to decreased performance. They were interested in this question based on a common occurance in endurance sports: Often, muscles are perceived to be exhausted before they actually run out of fuel.
All that said, it's not always possible to sleep long and well before every event. In the video below, elite athletes discuss how lack of sleep can be overcome when they're otherwise rested.