Polyphasic sleep is meant to let people get by with just a few hours of sleep and still be productive. We spoke with Dr. Ingo Fietze, Director of the Charité Interdisciplinary Center for Sleep Medicine, to find out if it works.Melanie Petersen
There are simply not enough hours in the day. Startup entrepreneurs and freelancers in particular can wish for a few extra hours in the day to get to everything on their calendar, to-do list and kanban board. But where can they steal these hours from? If only we could get back some of that time you have to spend sleeping, eating and getting dressed. Some are clever enough to have found a solution for the getting dressed part: they just wear the same outfit every day. Even when it comes to eating, there are already plenty of solutions from startups like Mana or Soylent, that reduce the time needed to prepare and eat meals. But what about sleep, the biggest time suck of all with the recommended eight hours a day? There must be something to be done here...
Alongside the old-school method of simply getting too little sleep, a new trend has developed that challenges the whole concept of eight-hour nights – polyphasic sleep models. The best known are called "Everyman," "Dymaxion" and "Uberman," and some people even create their own models.
The core feature is to minimize total sleep time by dividing it into at least three phases a day, with only some sleep happening at night. The Everyman model is based on a main sleep phase of 1.5 to 4.5 hours at night, along with two to three additional 20-minute phases. Uberman involves just six total sleep phases of 20 minutes each. With this method and strict avoidance of coffee and alcohol, it's supposed to be possible to reduce total sleep to as little as two hours and still be productive. But what do the experts say about it? Is it enough to feel productive? Does that mean that it's healthy? We discussed this with Dr. Ingo Fietze:
t3n.de: Dr. Fietze, what do you think of polyphasic sleep models? What would an alternative to classic nighttime sleep look like?
Ingo Fietze: To start with, there’s not a single long-term scientific study of these polyphasic sleep models. We would need these to be able to really say what long-term sleep behavior like this would do. Moreover, our sleep is governed by light and darkness, noise and quiet, lower body temperature at night and cortisol release in the morning. We operate on a 24-hour clock. Wanting to overcome that is a very ambitious prospect, and in my opinion cannot be successful.
Of course, many people do have to divide up their sleep time or sleep less, such as shift workers, but research shows that one out of every 25 can't manage this and stay healthy. It makes no sense to work against our natural rhythms that way. For a short time in exceptional situations it's certainly possible, but it's nothing to recommend beyond that.
t3n.de: So polyphasic sleep models are always unhealthy, even if you feel rested?
Fietze: Feeling rested despite insufficient sleep doesn't mean it's healthy. This year we learned that people who don't sleep well or sleep too little – or both – have a shorter life expectancy – above all because the immune system uses the night to regenerate and prepare for the next day. You don’t catch a cold straight away on the next day when you sleep badly, but over time you lose your protection from viruses and bacterial infections. Bones and muscles also need nighttime sleep to regenerate. For young people, regular and sufficient sleep is even more essential, because it's connected to growth. If I exaggerate a little, I would say if you take two adolescents and let one sleep normally, while the other tries a polyphasic sleep model with reduced sleep time, the first will grow and the second won’t.
What we can say in general is that the first four hours of sleep at night are the most important. They include the most deep sleep. Also, a sleep phase lasts around 90 to 100 minutes. If you take an afternoon nap, you should either have a 20-minute nap so you don’t fall into a deep sleep at all, or get a whole sleep cycle by giving yourself a good hour and a half.
t3n.de: Okay, so it's not a good idea. What do you think of sleep trackers that are supposed to help end nighttime sleep during a light sleep phase by waking people at the optimum time up to a half-hour before their alarm clock?
Fietze: First of all, the likelihood of being woken during a deep sleep phase in the morning is very low, maybe 20 percent. I'd rather enjoy every possible minute in bed, instead of people who generally are already not getting enough sleep losing another half-hour every day.