A 2017 online study of 31,000 participants over the age of 18 examined 3 million nights of sleep. Insufficient sleep was defined as having less than 6 hours of time in bed. “We find that, on average, it takes three nights to make up one insufficient night sleep and six nights to make up two insufficient nights of sleep in a row.” However, in this study, during the six nights of recovery sleep, there were no constraints regarding sleep duration and it is possible that during the 6-day recovery period, some individuals had additional nights of insufficient sleep.
I asked one author, Dr. Zeitzer, how fast recovery might occur if an individual actually obtained more than six hours of sleep each night during the recovery period. “I think that, based on laboratory studies, one could assume that baseline performance could be obtained after two nights (following one night of sleep loss) and probably three or four nights after two nights of sleep loss. If by ‘baseline’ performance, we mean an average performance after average sleep, then it’s probably one to two days of recovery per particularly bad day of sleep.” In other words, if your child is chronically a little short on sleep, the return to this baseline state might take one or two days of recovery sleep to make up for one night of insufficient sleep. This only applies to an individual whose baseline reflects mild habitual sleep deprivation.
However, Dr. Zeitzer added, “If by baseline performance we mean non-sleep-deprived performance, I think that most people would take a few weeks of good sleep” to completely recover.