How the body is affected by sleep deprivation and darkness

Maria Nordin, associate professor at the Department of Psychology.

ImageUlrika Sahlén

Maria Nordin's research is primarily focused on health psychology and work-related health psychology. Sleep is an integral component of our well-being and is an important factor to evaluate as sleep disturbances can be an indicator of potential health issues.

Why is it important to have a good night’s sleep?

Sleep is very important for our health. We are only now beginning to understand why we need to sleep. Recently, it has been shown that if we cleanse the brain figuratively, the brain is “washed” during sleep. We get a boost of growth hormone that repairs our cells. Our memory is rebuilt and improved, and we have better learning abilities. There are many good reasons why sleep is important.

Maria Nordin's top five tips for coping with the winter darkness

Why do we need to sleep so much?

So that all these processes can take their course and time. In the past, it has been said that you may not need as much sleep as recommended, but more and more research is showing that we need quite a lot of sleep to get all the processes in the body functioning during the night. The body does not actually ‘rest’, it does different things than it does during the day. But we need both the processes that happen at night and those that happen during the day.

Do we need more sleep in the winter months?

No. Not purely physiological. Physically, we don't need it. But it feels like it because we who live here in the north get more tired in the winter. This is because our sleep hormone, melatonin, is secreted into the body in the dark. It's the darkness that tells the body that now we should turn on the melatonin, and therefore we have higher melatonin levels in the body in the winter and we want to sleep more.

Lack of sleep and sleep disturbance over a long period can lead to serious conditions such as cardiovascular disease, chronic fatigue syndrome, stress and depression.

What happens if you don't get enough sleep?

Then we get tired. We have decreased learning ability and a reduced ability to concentrate. Lack of sleep and sleep disturbance over a long period can lead to serious conditions such as cardiovascular disease, chronic fatigue syndrome, stress and depression.

 

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How can we sleep better?

By making sure we go to bed at about the same time every day, even on weekends, and wake up at about the same time every day. Eating meals at regular times, having social gatherings during the day and living a healthy lifestyle. Physical activity is also highly beneficial.
 
During the winter, make sure you get outdoors, especially in the morning. Because the little light we have here in the north helps us keep our biological rhythm in check so that we can fall asleep at night. Sleep consists of two parts. The biological rhythm, which is set by a biological clock, and the sleep hormone. The biological clock is affected by light and when there is little light it can be disturbed so that we find it harder to sleep even if we are tired and it is dark. But a 30-minute walk in the morning, even when it's cloudy, and preferably every day, is enough to make it easier to set the biological clock.

If you are feeling stressed, what can you do so that it doesn’t affect your sleep?

As a matter of fact, stress and activity are the opposite of sleep - not wakefulness. Stress affects sleep to such an extent that if we have been very stressed during the day, it is difficult to settle down. It is also the case that the hormone that is active when we are awake - cortisol - is the opposite of melatonin. The two cannot be active at the same time in the body. So, if we have high levels of cortisol and are very awake and alert, then we find it difficult to wind down and sleep, and vice versa. If we sleep very late in the morning, for example, it can be difficult to get the cortisol going. Because it naturally wants to spike in the morning. Therefore, there's a strong link between stress and sleep.
 
What you should try to do is to maintain a balanced life. Live regularly and over a long period make sure you have as balanced an existence as possible where you're not always all wired up.

How are we affected when it gets darker?

We are affected a great deal by being more tired. And it's very much due to our physiological processes in the body. The sleep hormone we have called melatonin is secreted in the body when it’s dark. And therefore, we have higher levels of melatonin in our bodies when it's dark outside and for that reason, we become more tired.

We're adaptable and that's why we've been able to survive up here in the north.

Is coping with darkness harder for new Swedes coming from sunnier parts of the world?

It could very well be. It seems that you get used to where you live. We're probably more like biological creatures as we're probably adapted to more southern latitudes, but we're adaptable and that's why we've been able to survive up here in the north. But it's probably rather tough for a lot of people to come here in the dark.
 
It also requires a type of mindset to put up with this darkness. You need to be kind to yourself when you get tired and not put too much pressure on yourself, but instead try to make things cosy and nice.

Does light therapy work? And if so, how?

This is probably highly debated among scholars. Some research studies show it works to some extent. It was a big deal a few years ago, but it didn't have the impact that was hoped for. Some people feel good sitting in a bright room for a while. But it's probably important to do it in the morning so that the light has the right path length to activate the brain and control the release of melatonin. It controls our circadian rhythm better. But some sleep researchers say you can use a light therapy lamp on your desk. But it's best to keep it on for just one hour a day, preferably in the morning. For some, it works, for others not at all.

Maria Nordin's top five tips for coping with the winter darkness

1. Go outdoors for half an hour in the morning every day.
2. Eat, sleep and exercise regularly.
3. Just get moving. It doesn't have to be on an advanced level.
4. Go somewhere sunny to get some light in during this dark period.
5. Socialise with others. Be kind to yourself and allow yourself to have a little cosiness during the darker months.

Maria Nordin Associate professor

Email

+46 90 786 99 24

Note: This article was originally published in Swedish in December 2019. It was translated to English and updated in November 2022.