Sleep researcher Dr. Torbjörn Åkerstedt: The most common myths about sleep

Photographer: Andreas Andersson

Source: Karolinska Institutet

‍What are the most common myths about sleep that you still hear in the media and from the general public?

A common myth is that it is dangerous to deviate from the eight-hour norm for sleep duration. Anything between five and eight hours seems to be fine. People have different sleep engines.

Some people sleep very efficiently and need little sleep. The most important thing is to feel whether you are alert and refreshed during the day and functioning well.

Another myth is that sleep quality declines with age.

A third is that women sleep worse than men.

A fourth is that sleep before midnight is the most important. Instead, it is the first half of the night's sleep that is most important because that is when we have stage 3, which is deep sleep.

"Everyone needs eight hours of sleep" is one of the most widespread health rules. What does the research say about that?

Anything between five and eight hours seems to be fine. But people have different sleep engines. Some sleep very efficiently and need less sleep than others.

The most important thing is not to reach a certain number, but to feel whether you are alert and refreshed during the day and functioning well.

Sleep often changes from the age of 40 and up. What actually happens?

There is a slight increase in subjective sleep problems with increasing age, primarily fragmentation and early awakening.

If, on the other hand, you look at the feeling of being well-rested or alert during the day, it only gets better with the years, provided you are healthy.

Strangely enough, objective sleep recordings show that fragmentation increases while sleep duration and deep sleep decrease.

A reasonable interpretation is that the need for sleep decreases with age.

What consumes the most fuel in the brain is stress and learning. A 70-year-old is often done with most of their learning, has no demands from working life, and the family situation is often simpler. The need for recovery therefore becomes less.

You have researched sleep and stress for a long time. What does the relationship between them look like?

Stress triggers physiological arousal, which naturally disrupts sleep.

Stress or anxiety is often constant and can sometimes become chronic. It persists even when there is no objective reason for it.

There are a number of methods used in the psychological treatment of stress in general or specifically for sleep. The treatment model is often a form of cognitive behavioral therapy, CBT.

The method is well-supported by evidence and reduces problems for most people, though not for everyone.

Stress is naturally particularly difficult for people with a high baseline level of anxiety.

Sleep quality or sleep duration – which is more important?

There is still no clear answer to that question.

However, sleep duration is likely the most important factor. Poor quality often involves frequent awakenings and long periods of wakefulness, meaning duration and quality are often linked.

The ideal sleep duration is highly individual. People vary in their ability to sleep. Therefore, the correlation between sleep duration and fatigue is quite weak across individuals.

Some do well on five hours, while others need eight.

Within an individual, however, sleep duration is important. Most people have a sleep duration that allows them to function well, but if it is shortened by one or two hours, fatigue and reduced performance become clearly noticeable.

The best indicator of whether you are getting enough sleep is feeling alert and refreshed during the day.

The primary purpose of sleep is to maintain good performance during the day.

Which lifestyle factors have the strongest research support for better sleep?

1. Duration of wakefulness

The most powerful factor is likely the duration of wakefulness.

The longer you are awake, the better you sleep. Or conversely: the less you sleep, the better you will sleep the next time.

The sleep mechanism works in such a way that after a long period of wakefulness or little sleep, you fall asleep faster, produce more deep sleep, and experience fewer awakenings.

Sleep restriction, or time-in-bed restriction, is an important part of CBT for insomnia.

Sleeping too much, for example through naps, will lower the quality of subsequent sleep.

2. Regular sleep habits

Varying sleep habits from day to day reduce sleep quality.

The brain needs a stable pattern to provide optimal sleep.

3. Alcohol

Alcohol usually makes you fall asleep faster.

However, you wake up prematurely once your blood alcohol level drops to zero.

4. Nicotine and caffeine

Nicotine is a stimulant and leads to poorer sleep.

But if you use a lot of nicotine and are dependent, you may also experience sleep-disrupting withdrawal effects if you don't get your dose.

Caffeine has similar effects.

5. Winding down before bed

Relaxing and winding down before bed improves sleep.

Working and problem-solving before bed, on the other hand, disrupt sleep. The same applies to physical activity immediately before bedtime.

6. Movement during the day

Low-intensity activity such as walking and swimming during the day is beneficial for sleep.

You fall asleep more easily and sleep slightly better.

7. Eating habits

As for food, eating late or consuming large meals can cause digestive problems that disrupt sleep.