Exercising helps depression because it motivates people to get out and enjoy life again, scientists believe.
Researchers at University College London (UCL) reviewed research into the underlying mechanism of depression. They found that exercise reverses the damaging effects of inflammation.
Inflammation is linked to disrupted dopamine transmission, the feel-good hormone which brings feelings of pleasure, satisfaction, and motivation.
Disrupting dopamine appears to lead to changes in motivation, and in particular, a lower willingness to exert physical or mental effort.
But because exercise reduces inflammation and boosts dopamine function, it enhances motivation, providing an antidepressant effect.
Physical activity, especially aerobic exercise, has been found to reduce depressive symptoms, but until now the processes behind this have been poorly understood.
The team is now running a trial involving 250 participants which will test the antidepressant effects of exercise, whilst also measuring the effect on inflammation, dopamine transmission and motivation.
Lead author, Dr Emily Hird, of UCL’s Institute of Cognitive Neuroscience, said: “The antidepressant effect of aerobic exercise has been convincingly demonstrated through randomised controlled trials, but its mechanism is not well understood. This is, in part, because it likely involves a variety of biological and psychological processes.
“For example, alongside its positive effect on inflammation, dopamine and reward processing, exercise also reduces oxidative stress and improves self-esteem and self-efficacy.
“However, we are proposing that exercise – particularly aerobic activities that make you sweaty and out of breath – decreases inflammation and boosts dopamine transmission, which in turn increases the desire to exert effort, and therefore boosts motivation generally.”
Motivation is crucial for alleviating symptoms of depression, such as anhedonia, a lack of interest or joy in life’s experiences, as well as low energy and ‘brain fog’.
Boosting motivation could therefore lift the spirits and get rid of lethargy, the scientists believe.
Depression is the leading cause of disability worldwide, affecting one in six people in Britain, with women twice as likely to experience low mood compared with men.
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Previous studies have shown that the reasons for depression are complex, with personal circumstances, lifestyle factors and biology all playing a role.
The new review suggests that depression is also linked to disruptions to several brain and psychological processes, including impaired learning and memory.
Understanding why exercise boosts mood could encourage more people to increase their activity levels, while also giving doctors more confidence in social prescribing - advising patients how to improve their health by connecting them with local groups and communities.
Dr Hird added: “Addressing barriers to exercise – particularly in people with depression – is crucial, as regular physical activity may be able to alleviate symptoms, enhance mood and empower individuals on their path to recovery.
“As part of this, finding strategies to encourage exercise is key.”
The review was published in the journal Translational Psychiatry.
2024-07-27T10:52:14Z dg43tfdfdgfd