According to a new study, you don’t need to run, swim, bike or go to the gym to significantly reduce your chances of developing cancer. All it may take is just four minutes a day of vigorous intermittent physical activity like brisk walking or climbing the stairs.
The study by researchers from the UK, US, Australia, Canada, Norway and the Netherlands was published July 27 in the prestigious peer-reviewed Journal of the American Medical Association. It is garnering worldwide attention for apparently proving medicine’s long-held assumption that even minimal amounts of physical activity and exercise reduce a person’s cancer risks.
The study found that vigorous intermittent lifestyle physical activity (VILPA) in bursts of one or two minutes for a minimum of three and a half minutes a day was associated with a 17% to 18% reduction in total incident cancer risk compared with no VILPA. A median daily VILPA of 4.5 minutes was associated with a 31% to 32% reduction in the incidence of cancers reportedly linked to physical activity levels. These include colon, breast, bladder, endometrial, esophageal, kidney and stomach.
“It has its limitations, but it is a good proof of concept study. It means that doing something is better than doing nothing,” commented Prof. Ora Paltiel of the Hebrew University’s Braun School of Public Health and the Department of Hematology at Hadassah Medical Center.
The study involved 22,398 self-reported non-exercising adults from the UK Biobank, a large-scale biomedical database and research resource containing the medical and genetic data from half a million volunteer participants. The study subjects were 45.2% men and 54.8% women, and 96% white, with a mean age of 62.
The participants were followed for about six years and were given wrist accelerometers to measure their physical activity. However, they were not given any instructions other than to go about their daily lives.
“This is an observational study and not a clinical trial. So they didn’t tell people to walk up and down stairs or to climb a hill or something like that,” Paltiel said.
She believes that the study’s results are generally reliable given that its authors adjusted their analysis for age, sex, body mass index, education level, smoking status, alcohol consumption, sleep duration, fruit and vegetable consumption, medications, parental cancer history and prevalent cardiovascular disease, among other factors.
“The researchers went a long way to try to isolate this vigorous activity to show that it didn’t have to do with the baseline risks of those who did or did not do the activity,” Paltiel said.
“But we do need to consider that they didn’t know whether at baseline all the participants were 100% similar. The suspicion will always be that it’s not those four minutes of vigorous activity [that made the difference], but that the people who were capable [as opposed to those who were incapable] of doing the activity had a better outcome in the end,” Paltiel said.
Despite these reservations, Paltiel said that from a public health view, the study’s results are important.
“At the end of the day, it’s a very good message. It’s saying that even if your lifestyle doesn’t allow you to do regular physical activity or if exercise is not part of your mindset, you can potentially make a difference to your health by stressing your body a few times a day,” Paltiel noted.
Prof. Aron Popovtzer, head of Hadassah’s oncology department, told The Times of Israel that despite having the same reservations as Paltiel about the study, he believed its findings are positive and give traction to widely held theories about exercise and disease risk reduction.
“There has always been the thought within the medical and research community that cancer can be prevented by getting cells moving, by getting blood and free radicals flowing. We have also thought that exercise might boost the immune system,” Popovtzer said.
“We know that fat is related to cancer, so moving and not letting fat stagnate in one place in the body is a good thing,” he added.
Popovtzer cautioned that the outcome of the study does not indicate that one should limit oneself to just four minutes of VILPA a day. Nor does it mean that doing a lot of exercise will categorically prevent a person from getting cancer.
“We can’t from now on say that everyone who exercises for hours won’t get cancer. We all know that many people who do a lot of exercise find themselves with cancer,” he said.
Paltiel said the focus should be on the overall positive message of the study, which is that one does not have to meet the World Health Organization physical activity recommendations (150–300 minutes weekly of moderate-intensity aerobic physical activity) to begin reducing one’s risk of cancer.
“In Israel, most people live in apartment buildings, so take the stairs instead of the elevator. Walk a few minutes to a nearby destination instead of taking the bus, or park your car a distance from where you are going,” Paltiel suggested.
“People who get used to walking up the stairs might push themselves to do other things as well,” she said.