Just 20 minutes of moderate exercise a day can lower the risk of depression in adults aged over 50, according to new research from the University of Limerick.
A dose of physical activity equivalent to just 20 minutes a day (for five days a week) of moderate-intensity physical activity such as brisk walking, was linked with less risk of depressive symptoms and odds of major depression, researchers from the University of Limerick and Trinity College Dublin found in the new research, published in July.
The study, funded by Ireland’s Health Research Board, is published in the Jama Network Open journal. The cohort study followed 4,016 older adults, for a ten-year period, with participants having an average age of 61.
Lead author of the paper, Dr Eamon Laird, explained the findings:
“What is unique (about this study) that it is the first and largest investigation of a longitudinal cohort — with and without chronic disease — to try and work out what was the lowest minimal dose to observe a difference in depression,” he said.
“For this work, we used 10 years of data from the Irish Longitudinal Study On Ageing which included information on depression, MVPA, and other key health-related variables such as disease, lifestyle factors and socio-economic status.
“We sought to identify the lowest dose of MVPA associated with protection against Major Depression and depressive symptoms and the extent to which this varied based on the presence of chronic disease,” he added.
The study found that those who exercised for 20 minutes – such as brisk walking – for five days per week, had a 16% lower rate of depressive symptoms and 43% lower odds of suffering from major depression compared with those who did not exercise.
The more time people spent exercising, the bigger the benefits, the study found. Those who spent two hours a day exercising benefited the most – seeing a 23% reduction in depressive symptoms, and a 48% lower risk of major depression.
More moderate-intensity physical activity was associated with greater protection against depression, according to researchers. 120 minutes of such exercise daily for five days a week was associated with 23% lower risk of depressive symptoms and 49% lower odds of Major Depression.
Dr Laird, who is a postdoctoral researcher at the Department of Physical Education and Sport Sciences at UL, described the new findings as “very relevant” given the “high prevalence of depression” in Ireland’s increasing older population.
He said that at minimum, people should try to engage in 20 minutes a day of moderate-intensity activity for five days a week, with more benefits seen at higher doses.
“Try and build it into a routine with hobbies or activities you enjoy and trying to do it with others as social interactions particularly with activity can also have mental health benefits. Remember that it is one component, and that nutrition and a healthy lifestyle will also give additive benefits in addition to physical activity,” he said.
Meanwhile, Dr Matthew Herring, a Senior Lecturer and Investigator in the Physical Activity for Health Research Centre at UL and Principal Investigator of this HRB-funded research, said that the findings had “significant implications” in highlighting the antidepressant benefits which appear to be associated with doses of physical activity that are lower than the current WHO recommendations for overall health. He added that greater doses of exercise were associated with stronger protection against depression.
“We are clearly not advocating for lower physical activity among the older adult population, but findings suggest that the largest improvements in protection against depression among older adults may be made by engaging inactive older adults in physical activity even at doses below those recommended for overall health,” he said.