The findings are published in the American Journal of Epidemiology.
While some studies have shown links between reduced incidence of mild depression and regular physical exercise, many scientists cannot agree on whether physically active people are less likely to have depression and anxiety.
Research showing positive effects of exercise on heart health is already well established.
Researchers from the University of Bristol and Cardiff University, led by Dr Nicola J. Wiles, looked at the link between leisure time and work-related physical activity and common mental disorder, which is defined anxiety and depression.
They used data on 1,158 middle-aged men in Caerphilly, South Wales, who were followed for ten years from 1989.
The men filled in questionnaires about the amount of physical activity involved in their work and leisure time at the start of the study, and they completed questionnaires about anxiety and depression three times over the 10 year follow up.
The questionnaire used to assess physical activity was the Minnesota Leisure Time Physical Activity Questionnaire, and the mental health questionnaire was the General Health Questionnaire.
The researchers found that:
— The men who participated in any heavy-intensity leisure-time activity (eg running or playing football) were less likely to have depression or anxiety over the next 5 years compared with less active men.
— The effect was small but significant, and had worn off at the 10-year mark.
— Intense physical activity at work made no difference.
In speculating on their results, Dr Wiles and colleagues said they were consistent with othe studies looking at exercise and mild depression. They saw two reasons why these results occur.
One is the direct effect that exercise produces chemicals in the brain that affect mood, and the other is the indirect impact through enhanced body image and self-esteem.
Doctors are increasingly prescribing exercise as a way to get their sedentary patients more active.
A recent paper published in the Journal of Clinical Outcomes Management by two family doctors, Caroline Richardson and Thomas Schwenk, from the University of Michigan Health System lists some practical tips for primary care clinicians.
They suggest doctors write prescriptions for the type and duration of exercise their patients should undertake. Doctors could use techniques such as motivational interviewing in which the “physician helps patients explore their barriers to behavior change and to find ways to overcome these barriers”.
Richardson and Schwenk give examples of what doctors could suggest to help patients overcome those initial barriers:
— Take a 10-minute walk during your lunch break.
— Organize a walk with friends or family members at weekends.
— Walk on a treadmill while watching your favourite TV programme.
— Walk to work, or park a mile away and walk in when the weather is nice.
— Work out at home with exercise DVDs.
— Walk inside at a local mall, many of which open early for community walking clubs.
— School district swimming pools also may offer community hours.
— Explore the cost and availability of private and community-based recreation facilities.
— Find a safe building, perhaps at work, with stairwells or longer hallways that is available for lunchtime walks.
“Physical Activity and Common Mental Disorder: Results from the Caerphilly Study.”
Nicola J. Wiles, Anne M. Haase, John Gallacher, Debbie A. Lawlor, and Glyn Lewis.
Am. J. Epidemiol. 2007 165: 946-954
“Helping sedentary patients become more active: a practicial guide for the primary care physician.”
Richardson CR, Schwenk TL
J Clin Outcomes Manage 2007 Mar;14(3):161-171.
Written by: Catharine Paddock
Writer: Medical News Today