Only one hour of exercise per week is enough to help prevent depression, new research finds.
In the largest survey of its kind, the anxiety and depression levels of 33,908 Norwegians were monitored for more than 11 years.
The researchers concluded that just one hour of exercise a week reduced the chances of developing depression by a massive 44%.
Dr Samuel Harvey, the study's lead author, said:
"We've known for some time that exercise has a role to play in treating symptoms of depression, but this is the first time we have been able to quantify the preventative potential of physical activity in terms of reducing future levels of depression."The researchers also estimated that one hour of exercise would have prevented 12% of depression cases that occurred in their study.
Dr Harvey said:
"These findings are exciting because they show that even relatively small amounts of exercise - from one hour per week - can deliver significant protection against depression."Fascinatingly, that first hour of exercise turned out to be crucial, said Dr Harvey:
"Most of the mental health benefits of exercise are realised within the first hour undertaken each week.It is not known exactly why exercise has such a positive effect on mood disorders, said Dr Harvey:
With sedentary lifestyles becoming the norm worldwide, and rates of depression growing, these results are particularly pertinent as they highlight that even small lifestyle changes can reap significant mental health benefits."
"We are still trying to determine exactly why exercise can have this protective effect, but we believe it is from the combined impact of the various physical and social benefits of physical activity.
These results highlight the great potential to integrate exercise into individual mental health plans and broader public health campaigns.
If we can find ways to increase the population's level of physical activity even by a small amount, then this is likely to bring substantial physical and mental health benefits."
Comment: How exercise keeps depression at bay
A scientific review of multiple studies looked at what happens within our bodies during and after exercise that might affect and improve our moods. The researchers analyzed 20 past studies in which scientists had obtained blood samples from people with major depression before and after they had exercised. The samples on the whole indicated that exercise significantly reduced various markers of inflammation and increased levels of a number of different hormones and other biochemicals that are thought to contribute to brain health.
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