Many people know that exercise reduces the risk of forms of cancerincluding liver, lung, breast and kidney. But structured training is time-consuming, requires significant commitment and often financial outlay or travel to a gym. These practical conditions can make it impossible for most adults.
There is very little research on the possibility of occasional physical activity to reduce the risk of cancer.
Casual activities may include running errands on foot, work-related activity, or housework as part of daily routines.
As such, they do not require extra time commitment, special equipment or special practical arrangements.
In our examination today (July 27) we explored the health potential of short bursts of vigorous physical activity embedded in daily life.
It can be short power walks to get to the bus or tram stop, climbing stairs, dragging shopping, active housework or energetic play with children.
How was the survey conducted?
About 55 percent of the participants were women, with an average age of 62. Participants wore wrist activity trackers for one week. Such trackers monitor activity levels continuously and with a high level of detail throughout the day, allowing us to calculate how hard and precisely how long the subjects in the study moved.
Participants’ activity and other information were then linked to future cancer registries and other cancer-related health records for the next 6.7 years.
This meant that we could estimate the overall risk of cancer at different levels of what we call “vigorous intermittent physical activity in lifestyle“, the random bursts of activity in everyday life.
We also separately analyzed a group of 13 cancer sites in the body with more established links to exercise, such as breast, lung, liver and bowel cancer.
Our analyzes took into account other factors that influence cancer risk, such as age, smoking, diet and alcohol habits.
What we found out
Although the study participants did not do any structured exercise, about 94 percent recorded short bursts of exercise vigorous activity. About 92 percent of all matches were performed in very short bursts lasting up to a minute.
A minimum of about 3.5 minutes each day was associated with a 17-18 percent reduction in overall cancer risk compared to doing no such activity.
Half of the participants did at least 4.5 minutes a day, associated with a 20-21 percent reduction in overall cancer risk.
For cancers such as breast, lung and bowel cancer, which we know are affected by the amount of exercise people do, the results were stronger and the risk reduction sharper.
For example, a minimum of 3.5 minutes per day of vigorous casual activity reduced the risk of these cancers by 28-29 percent. At 4.5 minutes a day, these risks were reduced by 31-32 percent.
For both total cancers and those known to be associated with exercise, the results clearly show the benefits of doing daily activities with gusto that keep you huffing and puffing.
Our study had its limitations
The study is observational, meaning we looked at a group of people and their outcomes retrospectively and did not test new interventions. This means that it cannot directly explore cause and effect with certainty.
But we took several statistical measures to minimize the possibility that those with the lowest activity levels were not the unhealthiest and thus the most likely to get cancer—a phenomenon called “reverse causation“.
Our study cannot explain the biological mechanisms of how high-intensity activity can reduce cancer risk. Earlier early attempts show that this type of activity leads to rapid improvements in heart and lung fitness.
There is very little research on casual physical activity and cancer in general because most of the scientific evidence on lifestyle health behaviors and cancer is based on questionnaires.
This method does not capture short bursts of activity and is very inaccurate in measuring the random activities of daily life.
So the area of vigorous intensity activity and cancer risk is in its infancy, despite some very promising recent findings that vigorous activity in short bouts during the week could reduce health risks.
In another recent study of ours, we found benefits of daily vigorous intermittent lifestyle activity about the risk of death in general and death from cancer or cardiovascular causes.
In short: Get started with your daily routine
Our study found that 3 to 4 minutes of vigorous random activity each day is associated with reduced cancer risk. This is a very small amount of activity in comparison current recommendations 150-300 minutes of moderate intensity or 75-150 minutes of vigorous intensity activity per week.
Vigorous casual physical activity is a promising avenue for cancer prevention among people who cannot or are unmotivated to exercise in their spare time.
Our study also highlights the technology’s potential. These findings are just a glimpse of how wearables combined with machine learning – which our study used to identify short bursts of vigorous activity – can reveal health benefits of unexplored aspects of our lives.
The future potential impact of such technologies in preventing cancer and possibly multitude of others the ratios can be very large.