From the article: An longitudinal study of people who participated in Vasloppet, the world’s largest long-distance ski-race, held in Sweden showed that those participating in the race have lower incidence of bipolar disorder compared to the general population.

However, when performance in the race was considered, high performance women had higher risk of bipolar disorder than slower skiing women. This association was not found in men. The study was published in the International Journal of Bipolar Disorders.

Bipolar disorder is a complicated diagnosis. Its key feature are mood swings ranging from severely depressed to overactive manic episodes. Around 2-4% of the population are estimated to suffer from it.

The disorder typically begins with one or several depressive episodes, but these are later followed with at least one episode of mania or hypomania. Mania is a condition in which a person displays an over-the-top level of activity or energy, mood or behavior. It is characterized by feelings of invincibility, lack of sleep, racing thoughts and ideas, rapid talking and having false beliefs or perceptions.

Recent studies have linked bipolar disorder to around 10-year shorter life expectancy, for both men and women. This has been attributed to poor cardiovascular health and an increased risk of suicide of persons suffering from bipolar depression. Because bipolar disorder affects how energetic a person feels, many researchers have wondered whether exercise could have some bearing on the likelihood of developing bipolar disorder.

A large study in Sweden found people with the lowest fitness levels to have a higher risk of bipolar disorder. But are there any associations with an active lifestyle in general?

“Previous studies suggested that the preventive potential of physical activity for mental health could be substantial,” said study author Martina Svensson, an assistant researcher at Tomas Deierborg’s Experimental Neuroinflammation Laboratory at Lund University. “We were both interested in investigating this at a larger level.”