There is increasing evidence of a link between regular activity and improved mental health. Half an hour of exercise a day, six days a week, had effects equivalent to a course of prescribed medication for mildly depressed patients, according to one major study in 2005. Dr Andrea Dunn, director of behavioural research at the Cooper Institute in Denver, who published her findings in the American Journal of Preventative Medicine, concluded that around three hours of exercise a week “led to a substantial decrease in symptoms”.

Some mental health practitioners in America are gaining qualifications as fitness trainers in order to incorporate exercise into their treatment programmes. In Los Angeles, Wayne Sandler, a psychiatrist, has installed a pair of treadmills facing each other in his consulting room and says that many of his patients feel more comfortable unloading their problems as they run with him for 45 minutes.

A similar approach is taken by Washington-based psychotherapist Jane Cibel. She has her clients perform a 50-minute training session, including weights and cardiovascular work, in her clinic. It is effective, Cibel believes, because the relationship between patient and therapist is similar to that of a client and their personal trainer.“Once you put someone through a workout they also begin to see, via their physical accomplishments, that they are capable of ‘self-bettering’ behaviour,” she says.

Exercise is known to raise the brain’s levels of dopamine, serotonin and norepinephrine, all neurotransmitters that affect mood. These are the same chemicals that are controlled by antidepressant medications. Professor Ellen Billett and her colleagues at the sport science department of Nottingham Trent University have also found that levels of phenylethylamine, similar in structure to amphetamines, increase substantially during a workout to produce a significant mood-boosting effect. “You can restructure your brain with exercise,” Cibel says. “It triggers higher levels of brain chemicals that can reinforce positive emotion and behaviour.”

In Britain, the Mental Health Foundation (MHF) is running a year-long campaign to raise awareness of the benefits of exercise as a treatment for mild to moderate depression. Around three million people suffer from mental illness at any time, making it one of the most common medical conditions in the UK. Currently, only 5 per cent of doctors recommend physical activity as a cure for mild to moderate depression, despite advice from the Chief Medical Officer that exercise on prescription can be as effective.

As part of the Up And Running campaign, GPs are being urged to get more patients doing moderate activity. According to Ed Halliwell, who is working on the MHF campaign, “exercise schemes give people human contact and motivation which can boost their recovery”.

Times recommends

• What took place in 2010...
• Can you really cure a hangover?
• Video: How to do glamorous smoky eyes