There are many benefits to being physically active, but the new results suggest there are "specific effects also on the survival among prostate cancer patients," said the study's lead author Stephanie Bonn of the Karolinska Institute in Stockholm.
Read: What is prostate cancer?
"There is great potential for men diagnosed with prostate cancer to improve their own survival by being physically active," she wrote in an email to Reuters Health.
28 000 men die yearly
In the U.S. alone, about 210,000 men are diagnosed with prostate cancer every year and about 28,000 die of it, according to the Centres for Disease Control and Prevention (CDC).
Previous studies have found links between physical activity and survival in cancer patients, but few looked at prostate cancer, Bonn and her colleagues write in Cancer Epidemiology, Biomarkers and Prevention.
For the new study, they analysed data on 4,623 men from Sweden diagnosed with early-stage prostate cancer between 1997 and 2002. The information included details on the men's physical activity levels and general health until 2012.
Read: Symptoms of prostate cancer
Overall, the men who walked or biked daily for at least 20 minutes after their diagnosis had a 39 percent decreased risk of dying from prostate cancer and a 30 percent decreased risk of dying from any cause, compared to those who were less active.
For example, each year, among every 1,000 men who walked or biked at least 20 minutes a day, there were about 23 deaths from any cause, compared to about 38 deaths among every 1,000 men who exercised less.
Additionally, for every 1,000 men who exercised for an hour or more per week, there were about 21 deaths from any cause per year, compared to about 34 deaths among every 1,000 of those who exercised less.
Results were consistent
The results were consistent regardless of the type of treatment the men received for their prostate cancer, Bonn said.
"However, our results apply to men diagnosed with localized prostate cancer and only those men who were still alive a number of years after their diagnosis were included in the study," she said, adding that it most likely excludes men with more aggressive prostate cancers.
The new study can't prove that more exercise extended the men's lives, but Bonn said it would be interesting to conduct a trial to measure the long-term and short-term effects of physical activity on prostate cancer.
The researchers say the association between exercise and prostate cancer could be related to hormones, fat tissue or inflammation. They plan to further investigate the exact mechanisms.
Read: Treating prostate cancer
"At the moment we are working with a large study where men have donated both biological samples, and responded to a lifestyle questionnaire where physical activity was assessed in detail," Bonn said.
"We will study how different types of physical activity and also body weight may impact both the risk of prostate cancer as well as survival."
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Image: Mature man with towel and water bottle at gym from Shutterstock.