LAUSR

RATIONALE While sleep deprivation can alter endurance of skeletal muscles, its impact on respiratory command is unknown. We aimed to assess the effect of sleep deprivation on respiratory motor output and inspiratory endurance. METHODS Inspiratory endurance was investigated twice in random order, following a normal sleep night and a sleepless night. Healthy subjects were asked to breathe as long as possible until task failure against a moderate inspiratory threshold constraint. Transdiaphragmatic pressure and diaphragm electrical activity were measured throughout the trial to assess pressure output of diaphragm and overall respiratory motor output. Cortical contribution to respiratory motor output was assessed by measuring pre-inspiratory motor potential amplitude and with cervical magnetic simulation. RESULTS Twenty healthy males were studied. Time to task failure was significantly shorter after sleep deprivation than after normal sleep: (30min[17-41] vs. 60min[45-60], p=0.002). At the beginning of the trial, pre-inspiratory motor potential amplitude was significantly lower in sleep deprivation condition (4.5 µV[2.5-6.4] vs. 7.3µ[4.3-10.4], p=0.02) and correlated significantly with the duration of the endurance trial. In sleep deprivation condition, pre-inspiratory motor potential amplitude, electrical activity of the diaphragm, pressure output of the diaphragm and tidal volume decreased and the respiratory rate increased significantly from the beginning to the end of the trial. Such decreases did not occur in normal sleep condition. CONCLUSION One-night sleep deprivation reduces respiratory motor output by altering its cortical component with subsequent reduction of inspiratory endurance by half. These results suggest that altered sleep triggers severe brain dysfunctions that could precipitate respiratory failure. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT02725190.