In a recent study, researchers find that people who exercise report having 1.5 fewer days of poor mental health a month, compared to people who do not exercise.
The study included all types of physical activity, ranging from childcare, housework, lawn-mowing and fishing to cycling, going to the gym, running and skiing.
The team found that team sports, cycling, aerobics and going to the gym are associated with the biggest reductions.
But the results also show that more exercise was not always better. In fact, exercising for 45 minutes 3-5 times a week was associated with the biggest benefits.
The study involved 1.2 million people in the USA, and it is the biggest study in its research area.
Previous research has shown that exercise reduces the risk of cardiovascular disease, stroke, diabetes, and mortality from all causes, but its association with mental health remains unclear.
While some evidence suggests that exercise may improve mental health, the relationship could go both ways.
For example, inactivity could be a symptom of and contributor to poor mental health, and being active could be a sign of or contribute to resilience.
In the study, the researchers used data from 1.2 million adults across all 50 US states who completed the Behavioural Risk Factor Surveillance System survey in 2011, 2013, and 2015.
They checked the demographic data as well as information about people’s physical health, mental health, and health habits.
Participants were asked to estimate how many days in the past 30 days they would rate their mental health as ‘not good’ based on stress, depression and emotional problems.
They were also asked how often they took part in exercise in the past 30 days outside of their regular job, as well as how many times a week or month they did this exercise and for how long.
Overall, there were 75 types of exercise recorded, and these were grouped into eight categories—aerobic and gym exercise, cycling, household, team sports, recreational activity, running and jogging, walking, and winter or water sports.
The team found that on average, participants experienced 3.4 days of poor mental health each month.
Compared to people who reported doing no exercise, people who exercised reported 1.5 fewer days of poor mental health each month.
This is a reduction of 43.2% (2.0 days for people who exercised vs 3.4 days for people who did not exercise).
The reduction in number of poor mental health days was larger for people who had previously been diagnosed with depression.
In these people, exercise was linked to 3.75 fewer days of poor mental health compared with people who did not exercise—equivalent to a 34.5% reduction.
In addition, all types of exercise were associated with improved mental health, but the strongest associations for all participants were seen for team sports, cycling, aerobic and gym exercise.
The team also found that how often and for how long people exercised was also an important factor.
People who exercised between three and five times a week had better mental health than people who exercised less or more each week.
In particular, exercising for more than three hours a day was associated with worse mental health than not exercising at all.
The authors note that people doing extreme amounts of exercise might have obsessive characteristics which could place them at greater risk of poor mental health.
The researchers suggest that social activities may promote resilience and reduce depression by reducing social withdrawal and isolation, giving social sports an edge over other kinds.
Dr. Adam Chekroud, Assistant Professor of Psychiatry at Yale University, and Chief Scientist at Spring Health, USA, is one study author.
The study is published in The Lancet Psychiatry.
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Source: The Lancet Psychiatry.