What does exercise actually do for mental health?

A month ago in this blog I wrote about running a marathon, and the huge benefit I found that it had on my stress levels and overall well being. Thank you to all of you who have been in touch to share your own experiences of the effect of exercise on both physical well being and your mental health, and to those who have asked me more about the research surrounding this effect.


There have been a huge number of studies over the years, and I encourage you to do your own research and draw your own conclusions. That said, here are a few which I have found particularly striking in my own reading around the subject recently.

Exercise and Working Memory

A 2008 paper published in the Journal of Sport and Exercise Psychology details an experiment run by Sian Beilock and Ben Sibley into the effect of exercise on working memory. About 50 undergraduate students were asked to take a series of tests which evaluated their working memory. In one task, called Operation Span Task, students were instructed to solve a maths problem which appeared on a screen followed by a word. The students were to read aloud and solve each maths problem, then to read aloud the word and remember it. The sum and the word then disappeared from the screen. After a series of between three and five problems, students were asked to recall the words in the order they appeared. This was to test working memory: how well students could hold information in their memory while doing something else. After this initial test of working memory was completed, students were told to run on a treadmill for half an hour, at 60 to 80 percent of their maximum effort. The organisers then asked subjects to take part in another round of the test, and measured the change in working memory. They discovered that those who had showed the least amount of working memory to begin with experienced the greatest increase after exercise.

Exercise and Depression

A revolutionary study in 1999 by researchers at Duke University found that exercise is better than the SSRI drug sertraline at treating depression. In the study, called Standard Medical Intervention and Long-term Exercise and nicknamed SMILE for short, 156 patients were divided into three groups. Over a period of sixteen weeks, one group was prescribed sertraline, one group exercise, and one group a combination of the two. The exercise group took part in supervised walking or jogging at 70-85% effort for 30 minutes three times a week. Results showed that all three groups showed a drop in depression, with about half of each group in complete remission after sixteen weeks. The leader of the study concluded that in the short term exercise was as effective as the drug at treating depression. However, six months after the study finished, the researchers returned to the subjects to see how they were doing, and concluded that in the longer term exercise could be labelled as even better than the drug at treating depression. Only 30% of the exercise group still had symptoms of depression, compared to about 50% of both the medication group and the combined group.

Other Benefits

There has also been some research to suggest that exercise might be able to slow down the development of dementia, although this is not yet conclusive. Exercise has been shown to improve sleep – both in terms of falling asleep faster and sleeping longer and better.

The evidence for exercise as a benefit to mental wellbeing is overwhelming. It should be noted though that the benefits of exercise are increased when the subject enjoys the activity, and that too much exercise at too high an intensity can cause both physical and psychological harm. As with anything else, its best undertaken in healthy moderation, and under the advice of a doctor where necessary.

We'll look in more detail at physical well being and feeling good about your body through exercise later. For the time being I'm happy to say I didn't disgrace myself in the Edinburgh 10k a couple of weeks ago… although there is plenty of room for improvement!