How many hours should you sleep?
First of all: there is no single answer to questions about sleep – what is ideal for each individual can vary greatly. Furthermore, needs change depending on age and life circumstances.
Fashions and the spirit of the times also play a role: For centuries, it was perfectly normal to sleep intermittently at night, with breaks of one or even several hours. It is said that these breaks were sometimes even used and planned like an extra daytime, for example by doctors, scientists, the church – or privately for storytelling and reading.
Today, at least in Western societies, this is not desirable for most people. However, the phenomenon of interrupted sleep still occurs frequently and is known, for example, as the "wolf hour." Those affected wake up around three to four in the morning and are initially unable to fall back asleep. A relic from earlier times? Possibly – scientifically, waking up at this time is generally explained by hormone levels in conjunction with a drop in body temperature.
Those who know this from their own experience will probably not find comfort in this, as they simply want to sleep through the night - preferably 8 hours of sleep at a stretch, night after night: This is generally considered ideal for adults.
How much sleep do adults need?
There are no universally applicable rules regarding sleep requirements or how many hours of sleep one needs to feel rested. However, several surveys conclude that most people in Germany need more than Half of all people consider 7 to 9 hours of sleep sufficient. However, this apparently doesn't mean that people actually get that much sleep: A study commissioned by the Techniker Krankenkasse (a German health insurance company) found, for example, that around 60 percent of adults only get an average of 6 to 7 hours of sleep.
Far fewer percent report sleeping up to 12 hours – at the other end of the scale are those who manage with 5 hours of sleep or less. That this doesn't necessarily have to be detrimental to energy levels and work performance is demonstrated by prominent examples: from Winston Churchill and Napoleon to Thomas Edison – it is apparently no obstacle to being highly productive with less than five hours of sleep.
Overall, these three belong to a minority of approximately one percent of short sleepers, who consistently need less than six hours of sleep to start the day well. Like many things, genetic predisposition plays a crucial role in determining someone's sleep type. In practice, of course, this doesn't mean that one can live accordingly. Just consider former presidents like Barack Obama or former German Chancellor Angela Merkel, who had little opportunity to follow their natural sleep rhythm while in office. Obama is rumored to have used medication to shorten his sleep while maintaining the same level of performance. It's probably no coincidence that he once said, before the end of his presidency, that one of the first things he would do after leaving office would be to sleep for two weeks straight. And Merkel, who... Having earned a reputation for exceptional constitution during her long years in office, the then-Chancellor dispelled the rumor in an interview that she only needs four to five hours of sleep. To maintain a reasonably good mood, she explained, she regularly needs more than that.
How much sleep is too little?
Aside from a worse mood, what are the risks for those who sleep against their natural rhythm and therefore don't get enough rest at night? Scientists largely agree that chronic or prolonged sleep deprivation endangers health. "Too little sleep makes you stupid": This truism can be confirmed by students who prefer late nights out as well as by shift workers.
Impaired short-term memory, difficulty concentrating, and restlessness are among the less serious symptoms of poor or insufficient sleep. The German Society for Sleep Research and Sleep Medicine cites more serious consequences, including an increased risk of depression, heart disease, high blood pressure, and even certain types of cancer—not to mention that nearly one in four road accidents is attributed to drowsy driving.
It's obvious that trying to compensate for sleep problems with alcohol or pills is a bad idea. In both cases, addiction and further health problems are likely – and wine and beer, for example, don't even help in the short term. This is simply because alcohol dehydrates the body: as a result, you have to get up to urinate more often during the night and are also thirstier. Sleep researchers also warn that even small amounts of alcohol before bed reduce the quality of sleep. Even if falling asleep itself might be easier, the particularly important deep sleep phase is impaired. In the second half of the night, physical rest and regeneration are compromised when this sleep phase is shortened and interrupted by more frequent awakenings.
Is too much sleep unhealthy?
Too little sleep can lead to a decline in health. But what happens to the body and brain when people sleep too much? Studies show that excessive sleep is also harmful. People who sleep too much over a long period are more likely to develop illnesses, back pain, depression, and heart problems. However, the crucial factor is how you feel after a night's sleep. If you feel rested, refreshed, and able to perform at your best during the day, then even a long sleep duration can be the right amount of sleep.
Influence of sleep phases
The restorative value of sleep also depends on the different sleep phases that people go through several times during the night. Therefore, understanding these individual sleep phases is helpful in evaluating one's optimal sleep duration.
The sleep onset phase
The sleep onset phase belongs to the non-REM phase. Sleep during this phase is very light. The muscles are not yet fully relaxed. Brain activity slows down.
The light sleep phase
The second phase of non-REM sleep is the so-called light sleep phase. The muscles relax increasingly and the body temperature drops. Brain activity continues to decrease.
The deep sleep phase
During deep sleep, breathing and heart rate slow down. Blood pressure drops, and very slow brain waves can be detected. Deep sleep is also part of the non-REM phase.
The REM phase
REM stands for Rapid Eye Movement. The eyes move rapidly back and forth under the eyelids. While the body enters a state of complete relaxation, the brain processes the day's events. The areas responsible for long-term memory are particularly active during this phase. The REM phase is also the sleep stage in which people dream.
After the REM phase ends, the sleep cycle begins again. The body thus returns to the light sleep phase.
Our four tips for a healthy sleep, so you wake up refreshed
We have already shown that it is not only the duration of sleep that matters when it comes to healthy and restful sleep. Sleep quality is at least as important.
People can do something to improve their sleep quality. Below, we list the most important tips and tricks for increasing sleep quality.
Tip 1: Build up routines
Establishing a consistent sleep rhythm lays the foundation for restful sleep. The body can adjust to this regularity and adapt to the bedtime. Ideally, this routine should not be interrupted, even on weekends.
Tip 2: Exercise in everyday life
Regular exercise and sports also have a significant impact on sleep quality. Exercise leads to greater balance in everyday life and is therefore an important factor in increasing the level of restorative sleep.
Tip 3: Avoid alcohol and caffeine
In particular, the consumption of alcohol and caffeine immediately before going to bed leads to a negative impact on sleep quality.
In particular, consuming alcohol to relax after a stressful and demanding day is not a good idea in terms of sleep quality and prevents holistic recovery during sleep.
Tip 4: Improve your sleep quality with the right bedding.
The sleeping environment and the sensation of perspiration at night have a significant impact on sleep quality. Those who sweat profusely at night, in particular, often complain of restless nights. Temperature-regulating bedding, for example, can promote restful sleep and reduce night sweats .