One night of sleep restriction following heavy exercise impairs 3-km cycling time-trial performance in the morning

The goal of this project was to examine the influence of a single night of sleep restriction following heavy exercise on cycling time-trial (TT) performance and skeletal muscle function in the morning. Seven recreational cyclists (age, 24 +/- 7 years; peak oxygen consumption, 62 +/- 4 mL.kg(-1).min(-1)) completed 2 phases, each comprising evening (EX1) and next-morning (EX2) exercise sessions. EX1 and EX2 were separated by an assigned sleep condition: a full night of rest (CON; 7.1 +/- 0.3 h of sleep) or sleep restriction through early waking (SR; 2.4 +/- 0.2 h). EX1 comprised baseline testing (muscle soreness, isokinetic torque, and 3-km TT performance) followed by heavy exercise that included 60 min of high-intensity cycling intervals and resistance exercise. EX2 was performed to assess recovery from EX1 and included all baseline measures. Magnitude-based inferences were used to evaluate all variables. SR had a negative effect (very likely) on the change in 3-km TT performance compared with CON. Specifically, 3-km TT performance was 'very likely' slower during EX2 compared with EX1 following SR (-4.0% +/- 3.0%), whereas 3-km TT performance was 'possibly' slower during EX2 (vs. EX1) following CON (-0.5% +/- 3.0%). Sleep condition did not influence changes in peak torque or muscle soreness from EX1 to EX2. A single night of sleep restriction following heavy exercise had marked consequences on 3-km TT performance the next morning. Because occasional sleep loss is likely, strategies to ameliorate the consequences of sleep loss on performance should be investigated.