Take the stairs: Short bursts of energy found to reduce cancer risk
By Sarah Berry
Our lives might look very different today compared with 200,000 years ago, but our genetic make-up and physiology remain the same.
One attribute of this is the need to exert ourselves and get a little breathless every day, as we did when we had to chase down dinner or run from danger. Give our bodies this stimulus regularly, and we experience adaptations to our cardiovascular system and respiratory function, which decreases systemic inflammation and improves insulin resistance.
We might not need exercise gear, but we do need to get a little breathless if we want to benefit from physical activity.Credit: iStock
Not only do our bodies operate better when we move them in the way they need, but we reduce the likelihood of chronic disease. Previous research has shown that physical activity reduces the risk of cancer.
But, how much activity do we have to do and are the types of activities we may do in our daily lives – running for the bus or train, taking the stairs at work, carrying heavy loads of shopping, gardening, cleaning the house or running around with kids – as effective?
These questions have been hard for researchers to answer because they haven’t been able to measure our incidental activity. Fitness trackers have changed that.
A new study published today in JAMA Oncology reveals that getting breathless through incidental activity is no exception and a staggeringly small amount each day is effective for reducing our risk of cancer.
In the study, researchers from the University of Sydney, monitored the activity of 22,398 people who identified as “non-exercisers” and who wore fitness trackers for seven days. The health outcomes of the participants, who had an average age of 62, was then followed up over the course of seven years.
Compared with those who didn’t get their heart rate up at all, they found that just 3½ minutes a day of vigorous intermittent lifestyle physical activity (VILPA) was associated with up to 18 per cent reduction in cancer incidence, while 4½ minutes a day was associated with up to 32 per cent reduction in physical activity-related cancer incidence.
Most VILPA was typically accumulated from several one minute bursts across the day.
Lead author Emmanuel Stamatakis, a professor of physical activity and population health at the Charles Perkins Centre whose previous research found VILPA can extend our lifespan, expected there would be a reduction in cancer risk. Still, he says: “We’re surprised because the effect sizes are just staggering. We’re talking about very small amounts of physical activity.”
Professor Karen Canfell, the director of the Daffodil Centre, a joint research venture between Cancer Council NSW and the University of Sydney, says this really matters.
“More than 1800 cancer cases diagnosed in Australia this year are likely to be the direct result of physical inactivity, while many more will be indirectly related to physical inactivity because of its association with obesity, which is also a cancer risk factor,” Canfell says.
As it was an observational study, they cannot prove cause and effect, but Stamatakis says there are “very plausible” hypotheses, based on our needs as humans.
“Both insulin resistance and systemic inflammation are major risk factors for cancer,” he says. “So cardio-respiratory fitness improvements very plausibly can lead to improvements in major physiological processes that have established causal links with cancer.”
Rob Newton, a professor of exercise medicine at Edith Cowan University, says the public health message from the “striking” findings mean we should all aim for some form of vigorous daily activity, even if only for relatively short periods of time. However, he adds that individuals with a heightened risk of cancer should seek out a tailored program from an exercise physiologist.
“It is established that more vigorous physical activity, including exercise, has greater benefit for both reducing risk and treating all chronic diseases including cancer,” he says. “This is because more vigorous physical activity creates a greater disturbance to the homeostasis of all the body systems including the immune, endocrine, muscular and cardiorespiratory systems, which establishes and maintains a more anti-cancer environment within the body.”
Evelyn Parr, a researcher in nutrition and exercise physiology from the Australian Catholic University agrees, explaining that even one-minute bouts of exercise take time to recover from.
“By recover I mean reduce heart rate, breathing rate, body temperature and restore fuels used,” says Parr. “[This means] that the body is oscillating between intense activity and recovery from that activity, creating a dynamic system that has the potential to be protective of disease states like cancer.”
She says that while cause and effect cannot be distinguished from these outcomes, it opens the door to prospective studies collecting that data. And although the findings suggest every moment of movement matters, the physical activity guidelines of at least 2½ hours of moderately intense exercise each week, are still important for our health.
Stamatakis acknowledges that VILPA is no panacea, but it is encouraging for the 80 per cent of the population who are resistant to structured exercise or for those of us who struggle to fit exercise into their daily schedule.
While finding activities we enjoy can help us integrate them into our daily lives, it ought to become a priority for everyone regardless: movement is a biological necessity.
“Given the enormous volume of high-quality research, I am astounded that exercise is still viewed as a nice to have rather than a requirement for healthy living,” Newton says. “It is pretty well accepted that we should brush our teeth each day, and yet finding five to 10 minutes each day to perform vigorous physical activity would arguably have equal or much greater individual and population health benefit.”
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