Sunlight and lamps: How to brighten your mood in winter

Light improves our mood and is good for our bodies. But exactly how much do we need in order to notice the benefits and what are the effects of a walk in a sea of fog or a trip to the solarium?

Text: Katharina Rilling; photo: Unsplash

The days are short, winter is long, and we’ve also had to deal with coronavirus and all the bad news and restrictions that entails. Many are feeling down in the dumps at the moment. When you are feeling down, only one thing helps: Getting outside in the sun! Or at least that’s what people say. Do light showers really improve your mood, and are we generally worse off in autumn and winter than in summer? “Some people really are more gloomy and tired in winter than in the warmer months, but not all of us feel the effects so badly. Particularly robust individuals are able to adapt well to changing environmental conditions”, says Carolin Reichert, psychologist at the Centre for Chronobiology at the Universitätsklinik Basel.

The solarium is a waste of time

But daylight is healthy and important for all of us. It is linked to the 24-hour circadian rhythm, our internal clock. This rhythm is dictated by our brains, or more precisely, by the hypothalamus, although it is by no means precise. “We need certain timers in order to function properly and feel good”, says Reichart. “This can be mealtimes or activities. The most important timer, however, is daylight, which we perceive via the retina in our eyes. If the light information is transmitted to the hypothalamus, it triggers processes that make us feel awake, active andalert.” Which is why a sunbed does nothing to improve our mood. The mood-brightening effect of light therapy is achieved through the eyes, and you usually have to wear eye protection at solariums.

In general, our mood is better at the lightest part of the day than it is at nighttime. At nighttime, the pineal gland in our brains secretes melatonin which subdues us, makes us feel tired and helps us fall asleep. “It is darker for longer in winter, which can lead to the release of more melatonin.” This also explains why we tend to have a greater need for rest. Whereas light inhibits melatonin production and increases brain chemicals and the production of serotonin. These two properties of light contribute to the antidepressant effect.

Sunlight is better than artificial light

If you are often in a bad mood and feel tired in winter, you may find your mood improves if you go for a walk on a daily basis. It’s even worthwhile on cold and foggy days: “Daylight outdoors is still significantly better for your mood than the usual light indoors even if the weather is poor,” says Hellen Slawik, senior consultant at the Centre for Diagnostics and Crises Intervention and Zentrum für Affektive-, Stress- und Schlafstörungen (centre for affective-, stress and sleep disorders) at the University Psychiatric Clinics, Basel. Daylight is characterised by its high proportion of blue short-wave light. Light intensity outside amounts to between 2,000 and 10,000 lux (unit of illuminance), whereas light sources indoors use a much lower level of blue light and a far less intense light. Slawik recommends getting used to a fixed rhythm or schedule: “The internal clock really benefits when you get up regularly at the same time and go outside soon after getting up. The positive effect of light is felt most at this time of day for those suffering from depression.”

If you are suffering particularly hard: light therapy with daylight lamps

The senior consultant knows that people are affected by seasonal defective disorders, also known as winter depression, and recommends seeking treatment using daylight lamps if symptoms become severe. “Some people experience downright depressive episodes in autumn and winter which disappear again in spring and summer. Light therapy is the therapy of choice for people suffering from seasonal defective disorder and seasonal mood fluctuations.” During light therapy, you are subject to a light with an illumination level of 10,000 lux at a distance of 20 cm to 70 cm for a minimum of 30 minutes. It is important that the light contains sufficient blue light and a CE marking. The effects of light therapy should begin to be felt at the very latest after five weeks. Use of a daylight lamp should be at a carefully dosed rate and following agreement with your doctor. If you suffer from a disease that is associated with damage to the retina, such as diabetes, you should undertake an eye examination before undertaking any light therapy.  

According to placebo-controlled trials, light therapy can have a positive effect on a whole range of complaints and illnesses: For example for non-seasonal, bipolar, hormonal depression, dementia or elderly people suffering from sleep rhythm problems. It can also help those suffering from ADHS, Parkinson’s disease, schizophrenia, eating disorders borderline personality disorder, obsessive-compulsive disorder and panic attacks.

Replenishing vitamin D levels in the sun

And what about the vitamin D injection? “Vitamin D is produced in the skin when it is exposed to sunlight, which occurs less frequently in winter. A lack of vitamin D can have a negative effect on your mood and energy levels. This is however independent of the mood-brightening effect via the eyes, that inhibits the production of melatonin and encourages the production of serotonin,” says Carolin Reichart.

Good room light is no substitute for sunlight

Everyone is aware of the importance of light for our wellbeing, and architects are therefore increasingly considering light in their designs. For example in the orientation of hospital rooms in the direction of the compass. Or in the planning of intelligent lighting systems which change colour composition depending on the time of day. Reichert has mixed feelings about these developments: “I think it’s good and makes sense, but it shouldn’t lead to people spending less time outdoors, less time away from our desks and not moving around any more.” Modern mankind has been able to free itself a little from the natural day-night rhythm with these electric lights. But we are certainly not able to live without sunlight.