Sleep Deprivation in Healthy Males Increases Muscle Afferents, Impairing Motor Preparation and Reducing Endurance

Purpose: Sleep deprivation (SD) reduces time to task failure during endurance exercises. The aim of our work was to study the effect of acute SD on the endurance of a skeletal hand muscle and to investigate cortical motor drive to muscle and perception of effort.

Methods: Origin of the early exhaustion after SD might be insufficient cortical motor drive to muscle or motor inhibition because of excessive perception of effort. The supplementary motor area, the medial part of the premotor cortex, links the motor and sensory cortexes, prepares for voluntary movements, and may play a central role in the pathophysiology of impaired muscle endurance after SD. Supplementary motor area can be noninvasively assessed by electromyogram measuring amplitude of premotor potentials before hand movements. We investigated the effect of SD on muscle endurance in healthy volunteers performing moderate hand exercise by monitoring supplementary motor area activation and muscle afferents. Two sessions were performed, in random order, one after a normal sleep night and the other after a sleepless night.

Results: Twenty healthy young men were included in this study. Sleep deprivation reduced time to task failure by 11%. Supplementary motor area activation was altered throughout the task and effort perception was increased.

Conclusions: Our results suggest that SD reduces skeletal muscle endurance by increasing the effects of muscle afferents on the supplementary motor area. Sleep alterations frequently reported in chronic diseases might reduce patients' capacity to achieve the low-intensity motor exercises required in everyday life. Our results should lead to the search for sleep disorders in patients with chronic pathology.