The study found that exercising 8-10 a.m. showed the highest benefit in reducing the risk of both breast and prostate cancers.
Using a model they created, the scientists determined the risk of developing breast cancer was 25% lower in those who exercised early, compared to women who didn’t exercise at all. Men who exercised during the same time showed a 27% reduced risk of developing prostate cancer as compared to those who didn’t exercise.
The researchers also found that men who exercised 7-10 p.m. had a 25% lower risk of developing prostate cancer. No benefits from evening activity were seen in the group of women.
“Overall our findings indicate that time of the day of physical activity is an important aspect of physical activity that may potentiate the protective effect of physical activity on cancer risk,” the researchers wrote. “The effect of timing of physical activity on cancer risk should be examined in future research with a more detailed assessment of activity patterns, also including occupational activity.”