When you sleep for less than six hours, your body reacts like this.

A good night's sleep is essential! But what happens to our bodies if we don't get enough sleep for a few days? Ingo Fietze, a sleep researcher, reveals it.

Of course, getting enough sleep is critical to keeping healthy. That is something we are all aware of. Do we need to be concerned if we don't sleep well or sleep too little at times? Ingo Fietze, a senior physician for internal medicine and a sleep researcher at the Berlin Charité's Interdisciplinary Center, has the answers to these and other issues. He provides sleep workshops for managers, among other things, and will publish a book on the subject of sleep deprivation by the end of 2019. WirtschaftsWoche has now conducted an interview with him on the matter.

How about six hours of sleep? Concentration, bye-bye!

The average person sleeps seven to eight hours per night, which is sufficient for them to be fit and productive during the day. If they don't get this much sleep, it shows: those who sleep less than six hours in a single night score worse on concentration tests. As a result, according to Fietze, proper sleep is even more crucial for mentally demanding tasks than for physically demanding jobs.

Although there are also people who are so-called "short sleepers" and feel rested after only five to six hours, they are an exception. The same applies to "long sleepers" - the people concerned need nine to nine and a half hours of sleep every night. Either way, we can tell whether we've had enough sleep by the fact that we feel rested, get going quickly and don't suffer from recurring fatigue during the day.

What impact does a lack of sleep have on my health?

According to Fietze Risks, in addition to the concentration issues that might arise after just one night of little sleep, the risks of various illnesses increase over time. For the first time, sleeping poorly for two months may "only" be noticeable by the fact that you are more irritable than normal and overall feel more tired during the day. However, sleeping poorly for years, virtually nonstop, can increase your risk of developing the following diseases:

• High blood pressure and diabetes are examples of cardiovascular disorders (learn what it means to be diabetic here).
• Cancer

Live your life according to your internal clock.

Employees should be able to follow their own sleep needs in order to do their best work, and managers have a duty here as well. The so-called larks, who go to bed and wake up early, behave differently than the so-called owls, whose biorhythms keep them awake for long periods of time and who should be able to sleep longer as a result. This is where flextime may help.

And how can I get a restful night's sleep?

Ingo Fietze advises not to panic immediately if you haven't slept well for two or three nights. That only puts the body under stress and acts like a self-fulfilling prophecy: "I go to bed thinking that I'm not going to be able to sleep well again - and then that's exactly what happens. In addition, the sleep researcher considers sleep rituals such as relaxation techniques or breathing exercises to be useful.