Influence d'une privation partielle de sommeil sur l'adaptation à l'exercice physique

Abstract

Les effets d'une privation de trois heures de sommeil en milieu de nuit sur l'adaptation de l'organisme à un exercice physique ont été étudiés chez huit athlètes endurants de niveau régional. Les nuits de sommeil précédant l'effort ont été contrôlées en laboratoire. L'épreuve d'effort s'est déroulée sur bicyclette ergométrique. Sa chronologie a consisté en quatre étapes: échauffement de 10 minutes, effort sous-maximal à puissance fixe (75% de la consommation maximale d'oxygène) pendant 20 minutes, augmentation progressive de la charge de travail jusqu'à épuisement du sujet et, enfin, récupération de 15 minutes. À effort sous-maximal stable et à effort maximal supporté, les valeurs de fréquence cardiaque, de ventilation, d'équivalent respiratoire pour l'oxygène et de lactatémie sont plus élevées lorsque l'exercice est conduit après privation partielle de sommeil que celles obtenues lors de l'exercice effectué après une nuit témoin. À effort maximal, la consommation d'oxygène est abaissée alors que la puissance supportée de travail est identique. This study was aimed at investigating the effects of a partial sleep deprivation on the subsequent athletic performance. Eight highly trained cyclists were enrolled for this study. The changes in cardio-vascular, ventilatory and metabolic responses were analysed during and upon completion of physical exercise, taking place after 2 recorded nights, in other words, after a control night and after a night with reduced sleep. Partial sleep deprivation was obtained by waking the subjects for 3 h in the middle of the night. Athletic performance was tested at 2 pm the following day, using an ergometer. The subjects were pedaling at a steady-state submaximal work load (75% of the maximal oxygen uptake) and then at the maximal sustained work load. The analyses of change scores disclosed that there were main significant effects for measures of heart rate, ventilation, oxygen uptake, V̇E/V̇O 2 ratio and lactate levels under the observed conditions. Mean exercise duration and maximal sustained work load after partial sleep deprivation were not modified with control. On the other hand, heart rate was significantly greater during sub-maximal, maximal performances, and during recovery after sleep loss. Sleep deprivation significantly increased ventilation at exercise intensities eliciting 75% and 100% of the maximal oxygen uptake (V̇O 2 max) and during the recovery, since it significantly decreased V̇O 2 during maximal work. The V̇E/V̇O 2 ratio was greater at the end of the steady state and at the end of the maximal work load. Lactate levels were altered by sleep loss, undergoing upward drift from the 9th min of the steady state until recovery. These findings suggest that acute sleep loss may contribute to alterations in atlhetic performance.