You might not think that walking at full speed for two minutes to get to your flight on time or climbing four flights of stairs in a parking lot improves your health, but according to a new study, brief periods of physical activity such as these are linked to a significant reduction in the risk of death.
The international team of scientists behind the new study, published in Nature Medicine, dubbed these bursts of activity “vigorous intermittent lifestyle physical activity.” Using data from 25,241 people from the UK Biobank who reported not engaging in any physical activity or sport in their free time, scientists investigated whether ‘vigorous intermittent lifestyle physical activity’ was associated with changes in all-cause mortality or mortality from cardiovascular disease and cancer in those people who do not exercise.
3 minutes is enough to make your life longer and more fulfilling.
Asking participants to estimate their bouts of intense physical activity would be problematic at best. How would they correctly remember or characterize climbing stairs, moving furniture, or shoveling snow as “vigorous intermittent lifestyle physical activity”? Fortunately, all 25,241 subjects wore an accelerometer, so the researchers could see these physical activity sessions reflected clearly in the data.
After following participants for an average of 6 to 9 years, researchers found that participants who performed an average of three such bouts of intense physical activity per day, each lasting only one or two minutes, had a nearly 40% reduction in all-cause and cancer mortality. As well as a reduction of about 50% in mortality due to cardiovascular disease, compared to people who did not do it at all. Performing more of these physical activity sessions each day was linked to a further reduction in risk, although the benefits diminish when the total daily duration of the sessions exceeds about 12 minutes.
“People for whom structured exercise is not appealing or not feasible may consider introducing short, but regular bouts of intense physical activity into their daily routine,” the researchers commented. The use of accelerometers to measure physical activity was a particular strength of the study. The alternative – self-reported data – is easily biased by poor memory.
Is this really the case?
However, this work deserves some skepticism. While the effect reported by the researchers is likely real, it may not be as stunning as that reported for the average person. Keep in mind that the reduction in mortality is compared to that of people who are almost completely inactive, and so it is very possible that these people had unreported underlying health conditions.
The researchers say they took into account a large number of confounding variables, including age, smoking, alcohol, sleep duration, fruit and vegetable consumption, parental history of cardiovascular disease and cancer, and taking medication. However, they cannot rule out the possibility of reverse causation, that is, people who are already healthy may be more likely to engage in intense exercise. In other words, the arrow of causation could point the other way.
Nonetheless, the results are consistent with more controlled trials of high-intensity intermittent physical activity, which involves vigorous exercise for very brief periods interspersed with short breaks, lasting 10 to 15 minutes per day. This type of exercise provides the same benefits as longer-lasting moderate physical activity.
So go ahead, take the stairs instead of the elevator. Jog from your car to the restaurant rather than walking. This extra activity can’t hurt, and it might even reduce your risk of death.