A study found that chronic sleep restriction negatively affects athletic performance.

Results show that following sleep restriction, energy expenditure during submaximal exercise decreased 3.9%; maximal aerobic power decreased 2.9% and time to exhaustion decreased by 10.7% (37 seconds). Submaximal heart rate decreased after sleep restriction, as well as peak heart rate and Psychomotor Vigilance Test response speed.

“Our study is unique since we examined the relationship between sleep, physical performance, cognitive functioning, and physiology simultaneously,” says lead investigator, Cheri Mah, MS, Clinical and Translational Research Fellow with the University of California, San Francisco Human Performance Center, in a release. “Future studies are needed to better understand the physiologic responses to sleep restriction, and conversely sleep extension, to understand the dose response of sleep interventions on performance and health.”

The late-breaking research abstract was presented at the SLEEP 2016 meeting.

The randomized crossover study involved 12 healthy elite male cyclists who restricted sleep to 4 hours for three days or extended sleep to 10 hours for two weeks. Cyclists completed a baseline week of habitual sleep and a 2-week washout period in between interventions. Outcome measures pre and post intervention included: a 20-minute submaximal test, a 1-minute incremental maximal exercise test, and a maximal time to exhaustion test on a bicycle ergometer and metabolic collection system as well as the Psychomotor Vigilance Test.

The study was supported by National Center for Advancing Translational Sciences, National Institutes of Health, through UCSF-CTSI Grant Number TL1 TR000144. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.