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Why does exercise relieve depression?

Experts have for some time known that physical activity helps in cases of mild and moderate depression; however, there is some uncertainty concerning the reasons just why it helps. But now, researchers at Halmstad University, in a new study, give a comprehensive explanation for why exercise has a positive effect on depression.

The researchers have looked at a large number of other studies about what happens in the body and brain; both during physical activity, and when suffering from depression. The aim was to create a model that has highlighted all the factors that previous studies have determined.

– The body and brain work as a unit and there are many different mechanisms that contribute to why physical activity reduces depressive symptoms. Overall, one can say that exercise makes depression easier to deal with, says Torbjörn Josefsson, senior lecturer in psychology at Halmstad University and one of the researchers behind the new study.

Regular physical activity helps in cases of mild and moderate depression. Photo: JOACHIM BRINK

Alternative treatment is required

Over 300 million people worldwide have been diagnosed with depression. Depression is the third most common cause of disability and premature death in high-income countries such as Sweden.

– Previous research studies have proven that antidepressant medications have no effect in mild or moderate depression. Therefore, it is interesting with alternative methods to help people who suffer from this ailment, says Torbjörn Josefsson.

Torbjörn Josefsson and his colleagues established, in a meta-analysis in 2013, that regular physical activity helps in cases of mild and moderate depression.

– It is a proven fact that exercise has a positive effect on depression. However, there are many different hypotheses about why this is so. We wanted this new study to create an overall perspective; providing an explanation and a simpler model, says Torbjörn Josefsson.

The answers are many – the brain is affected in several ways

Depression often leads to concentration difficulties and negative thought patterns, so-called cognitive symptoms. Depression affects how an individual interprets situations, often making it difficult to see things from a different perspective than their own. However, during physical exercise, the so-called executive functions improve. These are controlled from the front of the brain (frontal lobe). They act as coordinators of various types of information and are behind all goal-orientated behaviour, such as planning and adaptability. This means that the cognitive symptoms can be reduced through exercise; therefore, helping the individual to deal with their depression more easily.

Depressed people often have a lower content of specific proteins in the brain; however, these levels increase during exercise. In addition, the memory and learning ability improves when undertaking physical activity – something that often deteriorates during a depression. Regular exercise also provides an improved self-esteem of the individual. This is probably a consequence of an improved physical self-esteem i.e. the individual becomes more satisfied with their body, which leads to a better global self-esteem.  A very common problem with depression is sleep disturbances but exercising enhances a better quality of sleep. Even anhedonia i.e. the inability of experiencing joy, desire and interest is reduced with regular exercise.

– Exercise can be likened to scaffolding – something stable to lean on. Hopefully, our research findings will lead to exercise being implemented as a clinical intervention for depression, says Torbjörn Josefsson.



About the Study

The research study is conducted in cooperation between Torbjörn Josefsson, School of Health and Welfare at Halmstad University, Trevor Archer, Department of Psychology at the University of Gothenburg and Magnus Lindwall, Department of Food and Nutrition, and Sport Science at the University of Gothenburg. The article titled: "Effects of Physical Exercise on Depressive Symptoms and Biomarkers in Depression" was published in February 2015 in the journal: CNS & Neurological Disorders - Drug Targets (link to the right).

Torbjörn Josefsson, senior lecturer in psychology at Halmstad University and one of the researchers behind the new study. Photo: LINDA LUNDELL

Updated 2015-05-06