Here's why four hours of sleep is terrible for you — even if you don't feel tired

Some people, including the president and many celebrities boast about being able to function on as little as hours of sleep. But is it necessarily good for you? Brad Stulberg, coauthor of "Peak Performance: Elevate your Game, Avoid Burnout and Thrive with the New Science of Success" explains why you should sleep more than four hours even if you don't feel tired.. Following is a transcript of the video.

I used to think of sleep as a very passive process but now I tend to think of sleep as very active. 

Sleep is one of the most productive things that we can do. We like to think that it's during the day that our minds are growing and that our bodies are getting stronger but it's actually quite the opposite. It's only when we sleep that both our physiology and psychology grows. So from a physiological standpoint, everything you do with your body, so just think about traditional exercise during the day, right? You are breaking your body down. And it's only during sleep that all the good growth-promoting hormones are released that allows your body to build back up.

What's really interesting is that the mind functions in a very similar manner. So during the day, you might be exposed to all kinds of information, do problem-solving, various types of what I guess would be categorized as "learning". We might think it's during the day when we are doing all the hard work, that we are getting wiser and our minds are growing per se. But much like the body, that also happens when we sleep. So it's when we sleep that our mind consolidates, stores and connects all the information that we've been exposed to during the day. It's a filtering process per se.

For a short period of time, if you need to get by in a few hours of sleep, let's say that you are a trauma surgeon, right? And you're on call and you have cases. That's totally fine, there's not much else that you can do. I think that where people get into trouble is when for an extended period of time, they try to cheat themselves of sleep. And then what happens is much like, almost like an alcohol addiction, that just becomes your new normal. So you get used to going on four to five hours of sleep and you assume that's just what it should feel like. When in fact, you probably can be a lot more productive a lot higher-performing if you slept more.