Many people who live in the northern part of the world suffer extended periods of darkness this time of the year - and often the winter blues. But there are things you can do to boost your health and wellbeing, and prevent winter depression.
Author
- Arne Lowden
Associate Professor of Psychology, Stockholm University
Several meteorological phenomena produce a lack of daylight. In research, we often refer to the number of hours with daylight as a photoperiod . At winter solstice, the photoperiod is short - or even absent if you go to the Arctic circle.
People living in Russia, Canada, northern USA and northern Europe get very little sunlight in winter. Capital cities like Oslo in Norway, Stockholm in Sweden and Helsinki in Finland are all situated above 59 degrees north. These densely populated areas have inhabitants who are particularly affected by a lack of light.
Another obstacle for people up north is the very low angle of the sun in the sky. Even if the sun rises above the horizon, it is often blocked by nature or buildings. Then there is the common thick layer of clouds that will cover the sun and reduce daylight exposure on most days, along with low temperatures.
Last year, Stockholm, where I live, had in total 13 hours of sunlight in November.
Another obvious obstacle for daylight exposure is our indoors lifestyle.
An interesting meteorological measure is the energy in terms of heat radiation coming from the sun, measured by a pyrometer . Sweden receives only 4% of all its yearly energy in December-February. Autumn is not very helpful either (14%), with the rest served in spring and summer (81%).
Light and mood
The consequence of living in the north is the very high risk of failing to obtain enough daylight. Throughout our evolutionary history, humans have naturally spent a lot of time outdoors to search for food, eat and perform work tasks in daylight. That's probably why our biological need for light is not an important to signal to the body, when compared to hunger or thirst, say.
When humans feel depressed, tired and drained of energy we don't normally connect this to lack of light. These signs show a similarity to jetlag (which occurs when the 24-hour circadian rhythm is out of balance to the 24-hour clock).
Most humans have a strong internal circadian rhythm that is slightly longer than 24 hours , especially people who are night owls. They favour a late bedtime and later get-up time in the morning. But the more daylight we get, the less likely we are to stay up late.
Daylight will promote an earlier onset of melatonin in the evening which will induce sleepiness and promote a "normal" bedtime. Indeed, a lack of light risks delaying bedtime and shortening sleep - making us even more sleepy in the dark season. Night owls who get a regular daily dose of natural light will turn into morning larks .
It is clear that light exposure has a huge affect on us, adjusting the internal rhythms of the body to align with the sun. Tackling problems with this internal rhythm supports alertness, mood and work performance , but also metabolic health.
Hack your light exposure
There are several ways to take action and conquer the winter blues. We have to remember that daylight is always ten times stronger outdoors than indoors. We need 30-120 minutes of daylight on a daily basis.
So what can we do to get enough sunlight in winter? It's important to go outside every day for a walk, even on cloudy days. Another good option is to sit as close as possible to a window when you're inside.
You should also embrace artificial light. It is less efficient than daylight, but still may improve alertness and mood . Ask for broadband spectrum LEDs in fixtures for your house and office.
For example, a light therapy lamp by the computer is helpful. Or you could install light corners (LED strips that are designed to fit into the corner where two surfaces meet).
Avoid strong lights in the evening though, especially blue light which is common in computers and electronic devices. This light suppresses melatonin at night which will make it harder to go to sleep. Watching TV at a distance is ok though.
You can also track the light on a light meter app on your phone to maximise your light exposure.
Ultimately, in winter, there is often more than 1000 lux (a unit of illuminance) at an open area under the sky. However, 60% is lost when coming close to a building while another 30% is lost through a window. Shockingly, only 1% is left a few meters from the window.
So if you live up north and are feeling down or tired in the winter, it may be time to try to hack your light habits.
Arne Lowden does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
