Tidying the House Soothes Mental Distress

By Crystal Phend
LONDON, April 10 2008-- As little as 20 minutes of physical activity a week, even if it's just routine housework, may be enough to provide mental health benefits, researchers found.
Note that higher intensity, more frequent exercise held more benefits but low intensity activity still provided some protection against psychological distress.
Note, too, that the cross-sectional nature of the study prevents determination of causality and the results could be explained by reverse causality or confounding from unmeasured variables.
Working around the house or garden for as little as 20 minutes once to three times a week reduced the odds of psychological distress by 24%, reported Mark Hamer, Ph.D., of the University College London, and colleagues in the British Journal of Sports Medicine.
However, more activity at a higher intensity improved the effect in a dose response manner with the strongest effects observed for sports (OR 0.67, 95% CI 0.54 to 0.82), they found in the population-based study.
Physical activity has been linked to depression, dementia, and cognitive decline, but how much and what type is best for mental health remained unclear, the researchers said.
So, they examined self-reported participation in all types of physical activity and current mental health among a nationally representative sample of 19,842 men and women 16 and older in the Scottish Health Surveys in 1995, 1998, and 2003.
Participants completed a 12-item General Health Questionnaire to provide details on psychological distress and trained interviewers elicited information on potentially confounding factors such as disease history and health behaviors.
Overall, 3,200 men and women were classified as having psychological distress. About 32% of them did not participate in any physical activity aside from housework or gardening or had one session a week that lasted at least 20 minutes.
All types of activity independently reduced the odds of psychological distress after adjustment for illness, smoking and marital status, gender, age, socioeconomic status, body mass index, and other types of exercise.
Increasing overall activity reduced the likelihood of having a psychological distress score of four points or higher on the General Health Questionnaire (P<0.001 for trend). The findings were:
33% reduction for activity sessions more than 3.5 to five times a week (OR 0.67, 95% CI 0.61 to 0.75).
33% reduction for activity sessions more than five to 6.75 times a week (OR 0.67, 95% CI 0.59 to 0.76).
41% reduction for activity sessions more than 6.75 times a week (OR 0.59, 95% CI 0.52 to 0.66).
For domestic activity -- housework and gardening -- as little as 20 minutes once a week to three times a week was associated with 24% lower odds of psychological distress (OR 0.76, 95% CI 0.69 to 0.84). Four or more such sessions per week were associated with a similar 16% improvement (OR 0.84, 95% CI 0.72 to 0.98).
Walking was associated with a 13% improvement in the likelihood of psychological distress whether once to three times a week or four or more times a week (OR 0.87, 95% CI 0.78 to 0.97 and 0.79 to 0.95, respectively).
Sports activities yielded the greatest benefits and was the only individual activity looked at that had a dose-response association in which greater participation reduced the likelihood of psychological distress (P<0.001 for trend).
Sports may have additional benefits through a "psychological component, such as fostering social support networks and developing mastery and better coping abilities," the researchers said.
The benefits of physical activity in general could be by reducing biological stress reactivity, "given that heightened responsiveness to daily stressors is a risk factor for psychological morbidity," they said. Exercise might also improve biological risk factors such as dyslipidemia, glucose intolerance, inflammation, and vascular dysfunction, "which have been related to mental health disorders such as depression and dementia."
The researchers cautioned, though, that the cross-sectional study could not prove causality and could have been affected by confounding from comorbidities that cause functional impairment or unmeasured variables.
The Scottish Health Survey was funded by the Scottish Executive. The researchers reported receiving grant funding from the British Heart Foundation and the National Institute for Health Research. The researchers reported no conflicts of interest.
Primary source: British Journal of Sports MedicineSource reference:Hamer M, et al "Dose-response relationship between physical activity and mental health: The Scottish Health Survey" Br J Sports Med 2008.