Exercise: an all-natural antidepressant?

There are many good reasons to exercise. To name a few: building muscle mass, shredding body fat or finally using that gym membership you got when you made that new year’s resolution! However, what better reason than if it could treat depression?

According to the World Health Organisation (WHO), depression is a common mental disorder which affects more than 264 million people of all ages. Depression is commonly treated with antidepressants and/or psychotherapy (e.g. CBT – Cognitive Behavioural Therapy), but some people may prefer alternative approaches such as exercise.

It’s not unknown that exercise contains many health benefits, such as protecting against heart disease and diabetes, improving sleep, and lowering blood pressure. But can exercise really improve our mood?

The science behind it: high-intensity exercise releases the body's feel-good chemicals called endorphins, resulting in the "runner's high" that joggers report. Low-intensity exercise, sustained over time, spurs the release of proteins called neurotrophic or growth factors, which cause nerve cells to grow and make new connections. The improvement in brain function makes you feel better.

In randomised controlled trials in which exercise was compared to standard treatment, no treatment or a placebo treatment in adults (aged 18 and over) with depression, two review authors extracted data on outcomes at the end of the trial, then used the data to calculate a standardised mean difference (SMD) for the overall pooled effect of exercise on depression, using a random‐effects model.

Results: For the trials comparing exercise with no treatment or a control intervention, the pooled SMD for the primary outcome of depression at the end of treatment was ‐0.62, indicating a moderate clinical effect. However, for the trials comparing exercise with psychological therapy, there was no significant difference (SMD ‐0.03).


So what’s the verdict?
Exercise seems to improve depressive symptoms in people with a diagnosis of depression when compared with no treatment or control intervention. Regular exercise can boost your mood if you have depression, and it’s especially useful for people with mild to moderate depression. Exercise alone, however, isn’t enough for someone with severe depression.
N.B. that the current NHS activity guidelines state that adults ages 19-64 should do at least 150 minutes of moderate intensity activity a week or 75 minutes of vigorous intensity activity a week.

What does this mean per day?
Some moderate intensity activities could include:

  • Walking/ cycling to work
  • Gardening/ cleaning the house
  • A friendly game of doubles tennis
  • Taking the dog for a brisk walk

Vigorous intensity activity includes:

  • Jogging/ running around your local park
  • Sports like football, rugby, netball and hockey
  • High Intensity Interval Training (HIIT) or CrossFit (you can find free workouts online)
  • Swimming laps
  • Hiking

For a moderate to vigorous workout, try “Couch to 5K”, a free program that will transform you from a couch potato to a 5K runner in 9 weeks.

Just remember that there are many forms of exercise and to pick and choose the ones that you find the most enjoyable.

References

Sophia Sood Year 12, The Sixth Form College Farnborough

Milad Rouf Final Year Medical Student, Cardiff University.

Cooney, G., Dwan, K., Greig, C., Lawlor, D., Rimer, J., Waugh, F., McMurdo, M. and Mead, G., 2013. Exercise for depression. Cochrane Database of Systematic Reviews.

Erickson, K., Miller, D. and Roecklein, K., 2011. The Aging Hippocampus. The Neuroscientist, 18(1), pp.82-97.