Arnold Schwarzenegger famously (and half-jokingly) proclaimed that if you need more than 6 hours of sleep, you should sleep faster. Many successful people claim to sleep very little and use the extra time to be productive.
But is this sound advise? I talked with Dr. Lars Dittrich, neuroscientist and former sleep researcher, about sleep.
Lars answer questions like What does sleep do? How is it regulated? What are the side-effects of acute and chronic sleep deprivation? How do I know if I sleep enough? How could sleep research inform policies and business practices?
Sleep deprivation, even only short-term, has significant effects on your cognitive abilities. Just a single night of lost sleep has the same effects as the amount of alcohol that would make driving illegal.
This tiredness is believed to be a mechanism that dials down the activity of the brain to reduce the accumulation of metabolites that may damage the brain. During sleep, these metabolites are cleared out of the brain. It is also the time for certain cognitive housekeeping functions, such as memory consolidation.
Sleepiness is regulated through two parameters: the time since you last slept, and the time of the day according to your internal circadian clock. Both the preferred sleep duration as well as the timing of sleep in the day are different between people. On average we need between roundabout 8 hrs of sleep.
If we force ourselves to sleep fewer hours per night than we need, this can have harsh health consequences, from cognitive decline to an increased risk for metabolic diseases – in particular diabetes – and possibly dementia.
As teenagers, and when we move the time at which we have to get up to an earlier phase of the internal clock, we are awake at times that our circadian rhythm says is too early. Accordingly, we are more tired, and suffer from some reduced cognitive ability.
Because of this scientist wonder whether it would be beneficial to have high school start later. And if we want to get rid of clock changes altogether, it would be better to permanently stick to standard time, rather than having daylight saving time all year round.
Anyways, our conclusion can only be to better not take the advice from people like Schwarzenegger on sleep too seriously. I mean, especially someone like Schwarzenegger should know that lack of recovery time kills your muscle gains!