In northern Europe the sun is a rare sight during the winter. And although most people would like to see more of it, for some people a lack of sunlight actually makes them ill.
In Northern Europe and the US, every winter, around three to five percent of the population suffers from Seasonal Affective Disorder (SAD).
The disorder has been recognised by the medical profession since the 1980s and is linked to a lack of light. Symptoms include sleeping too much, difficulty concentrating, and putting on weight – all of which it is thought result from the body going into a sort of hibernation mode.
Professor Damien Leger Centre de Sommeil de l’Hotel Dieu Paris explained: “Light allows all the bodies rhythms to function correctly. Light synchronises the body’s rhythms and the hormones as well as sleeping and waking hours, and body temperature. Probably these positive effects are missing in the winter.”
At the Sleep Centre in Paris they have a light therapy room. According to researchers, light therapy is cheap, it usually works within a week and has virtually no side effects. They use special lamps which do not emit UV rays which protects the skin and the eyes. The light emitted during this therapy is only 10 percent of the light a person would receive during a sunny summer’s day, but it is sufficient to alleviate symptoms.
Some people opt for light therapy at home. The lamps cost around 200 euros in the shops and the results show that they can be from 50 to 85 percent as effective as anti-depressant drugs.