Short bursts of vigorous physical activity can provide major health benefits
A sedentary lifestyle eventually takes a toll on health but snapping out of prolonged inactivity can be daunting. Now, however, there may be a simple way to ease into more activity. A recent study suggests that short bursts of vigorous activity every day — climbing stairs, carrying a heavy load of groceries, or stepping up the pace of housework — can provide substantial health benefits.
“It’s quite simple, but it’s not an idea that’s out there,” says University of Sydney exercise scientist Emmanuel Stamatakis who led the research. “Majority of the people, but also many health professionals still think of physical activity as something that you do during your free time, and you need to go somewhere to do it.”
His team found that engaging in three one-minute bursts of intense physical activity every day can lower a person’s risk of death by up to 40 percent. Such short but vigorous periods of activity similarly reduced the chances of dying from cancer or cardiovascular disease.
To maximize health benefits, Stamatakis recommends amping up the intensity of everyday activities. But he acknowledges that the health outcomes from doing regular exercise four or five times a week, for instance, are obviously superior. “There’s no doubt about that.”
State of inactivity
About 25 percent of adults in the United States are physically inactive and 60 percent aren’t regularly active, according to the Centers for Disease Control and Prevention. Not doing enough physical activity increases a person’s risks of getting type 2 diabetes, cardiovascular disease, developing anxiety and depression, and dying early.
The U.S. Department of Health and Human Services recommends at least 150 to 300 minutes a week of moderate-intensity physical activities, such as brisk walking or raking leaves, or 75 to 150 minutes of jogging, running, or shoveling snow, which are more vigorous, to gain health benefits. But recommendations like these are often drawn from questionnaire-based studies which tend to capture people who exercise long durations or bouts typically exceeding 10 minutes, Stamatakis says.
In recent years, there’s an acknowledgement and increased emphasis on the idea that all activity counts, he says. But the outcomes are intensity-dependent.
A few small studies have looked at the impact of brief bursts of high intensity physical activity have on health. Edward Coyle, an exercise physiologist at the University of Texas, has been exploring how four-second bursts of rigorous physical activity can offset harmful effects of sitting for prolonged periods. He conducted a small study in which young adults pedaled a stationary exercise bike as fast as they could five times every hour for four-second sprints over an eight-hour study period. His team noted that these tiny bursts of activity improved fat metabolism. “I was surprised to find how effective these four-second spurts were,” he says. “They’re equally effective to doing 30 minutes of continuous exercise,” he says.
Stamatakis and his colleagues, on the other hand, were keen to understand if daily life activities done somewhat vigorously in short bouts could also provide health benefits compared to a sedentary or less active lifestyle.
Using wearable devices to track activity
To study this, his team used data from Fitbit-like devices worn by nearly 25,000 adults who identified as non-exercisers. Over the course of seven days, they used machine learning tools to determine whether a person was either sedentary, standing, walking, or engaging in high-intensity activities like running during consecutive 10-second windows. The researchers also categorized any movement into light, moderate, or high intensity. Then, for the next seven years, they kept track of which study participants died and what caused the fatality.
The team found that people who engaged in at least four one-to-two-minute, high intensity physical activity bursts every day had a nearly 40 percent less risk of dying from cancer and a roughly 49 percent lower chance of dying from a cardiovascular disease. More bouts of such vigorous activity meant greater protection from mortality risks, Stamatakis says. “The more, the better.”
These outcomes surprised Coyle, who wasn’t involved in the research. He was stumped to see the benefits that people accrued with very little activity that wasn’t even formal exercise.
The study was an observational one and looked at associations between physical activity and mortality risks, so the researchers don’t know why these brief spurts of somewhat intense physical activity protect people. Hassane Zouhal, an exercise physiologist at the University of Rennes 2 in France who was not involved in the study, thinks that such movements could also raise the heart rate to provide some health benefits, but he emphasizes that either the intensity, duration, or both are key.
For now, the biggest takeaway is to move more and sit less, says Matthew Ahmadi, a research fellow at the University of Sydney and co-author of the study. “But while doing those activities, if you can just increase your pace for a short period of time, you can maximize your personal health benefits.”
Credit: National Geographic