Researchers suggest that the antidepressant effects of exercise might stem from its ability to decrease inflammation and enhance dopamine function, thus improving motivation.
Their findings indicate that aerobic activities could be key in treating depression through personalized exercise programs.
Exploring the Link Between Exercise and Depression Relief
UCL researchers have investigated how physical exercise helps reduce depressive symptoms by examining its effects on the brain and body.
Depression, the leading cause of disability worldwide, disrupts key brain and psychological processes, including learning, memory, and motivation. While aerobic exercise has been shown to alleviate depressive symptoms, the underlying mechanisms have remained unclear.
Hypothesizing Exercise’s Antidepressant Mechanisms
In a recent review published in the scientific journal Translational Psychiatry, researchers suggest a new hypothesis centered on motivation. They propose that exercise addresses symptoms of depression like anhedonia (loss of interest or pleasure in life’s experiences), low energy, and “brain fog” by boosting motivation, a critical factor in recovery.
Biological Insights Into Depression and Exercise
The team summarised research papers that explored the mechanisms of depression in both humans and animals and concluded that depression, especially anhedonia, is associated with elevated inflammation (caused by the body’s immune response). Importantly, inflammation is also linked to disrupted dopamine transmission. These biological changes may represent key processes leading to changes in motivation, and in particular, a lower willingness to exert physical or mental effort.
Exercise as an Antidepressant Tool
Meanwhile, exercise reduces inflammation, boosts dopamine function, and enhances motivation. The researchers believe that this could be an important reason as to why exercise exerts an antidepressant effect.
Lead author, Dr. Emily Hird (UCL Institute of Cognitive Neuroscience) said: “The antidepressant effect of aerobic exercise has been convincingly demonstrated through randomized 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.”
Personalised Treatment and Social Prescribing
The team hopes that this understanding of how exercise reduces symptoms of depression will help to inform the development of new treatment strategies – such as personalized exercise programs.
Dr. Hird said: “Understanding the mechanisms that underly the antidepressant effects of physical activity in depression could also inform our understanding of the mechanisms causing depression and the development of novel intervention strategies, in particular personalized intervention, and social prescribing.”
Future Research and Overcoming Barriers
To further test their hypothesis, the researchers advise that large randomized controlled trials need to be conducted that assess the antidepressant effects of exercise, whilst also measuring the effect on variables including inflammation, dopamine transmission, and motivation.
It would also be important to investigate any potential barriers to exercise.
Dr. Hird said: “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 team is now running a trial based on the hypothesis proposed in the review, which will involve 250 participants aged 18 to 60 and is funded by a Wellcome Mental Health Award.
Reference: “From movement to motivation: a proposed framework to understand the antidepressant effect of exercise” by E. J. Hird, A. Slanina-Davies, G. Lewis, M. Hamer and J. P. Roiser, 4 July 2024, Translational Psychiatry.
DOI: 10.1038/s41398-024-02922-y
The review paper was funded by the Rosetrees Trust.
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1 Comment
Maybe, but I personally don’t need to break a sweat to get happy; on the other hand I don’t suffer from a major depressive disorder either, which is probably what the article was referring to.