These conclusions are based on the reactions of forty people who slept at least 8 hours of sleep the day before, collected on a driving simulator and with electrodes.
“Behind all this there is the central clock, which controls a phase of hypovigilance (intermediate state between waking and sleeping, during which the faculties of analysis and observation are reduced) at the beginning of the afternoon , to allow you to sleep if you wish “, explains Damien Davenne, chronobiologist and professor at the university and director of the COMETE research unit at Inserm / Unicaen, dedicated to mobility. He led this study funded by the Vinci Autoroutes foundation.
For the purposes of this study, forty “good sleepers” (at least 8 hours of sleep the day before) performed on a driving simulator and with electrodes measuring several cognitive variables (fatigue, drowsiness, vigilance, anxiety), a monotonous motorway journey (without traffic, with a ban on leaving their lane).
This trip was sequenced in two times two hours of driving, interspersed with an hour of break including an identical lunch for each participant. During this break, a first group took a nap in a bed after the snack, a second slept on the reclining seat of the vehicle and the last just a simple break.
Result: for two hours after stopping, the lateral deviations of the vehicle (zigzags synonymous with loss of alertness or even drowsiness) of people who have not slept are 21% higher than those of those who took a nap. The difference is much less between participants who slept in a bed and on the seat. The delta is even + 80% between the 40th and 50th minutes after taking the wheel again. “The nap is essential when making a long trip. Ten or fifteen minutes are enough, after that come into play inertia mechanisms of sleep (waking up still asleep) detrimental to driving”, concludes