The researchers also looked at an unusually small serving of exercise, only four minutes in total, spread throughout the day. But the impacts still managed to “be meaningful” for people’s health, Little said.
“I think this study extends our understanding on the effect and application of exercise snacks in workplace settings,” said Kathryn Weston, a senior lecturer in physical activity at the University of Strathclyde in Glasgow, Scotland. She studies exercise snacks but wasn’t involved with the new study.
“Exercise snacks are a worthwhile, simple and generally accessible way of building short bouts of exercise” into our daily lives, she continued.
“It’s important to remember that every minute of exercise counts.”
Why snack on exercise?
Most American adults don’t exercise much. According to the Centres for Disease Control and Prevention, fewer than a quarter of us meet the current governmental exercise guidelines, which recommend at least 150 minutes a week of moderate exercise and two days a week of resistance training.
We also sit for long hours, studies show: many adults spend eight or more hours chairbound every day.
Both too little exercise and too much sedentary time are bad for us, separately and in combination. Even active people who meet the exercise guidelines but then sit for eight to 10 hours a day are at heightened risk for metabolic problems, including poor blood sugar control.
Exercise snacks are a fun-size potential solution to both too little exercise and too much sitting, Little said, requiring a surprisingly small time commitment and no changes of clothing or visits to the gym.
“Many people continue to cite a perceived lack of time as a major barrier” to getting exercise, said Martin Gibala, a professor of kinesiology at McMaster University in Ontario, Canada, and co-author of the new study.
That’s not an issue with exercise snacks, he added. By definition, they consist of simple movements, like squats or running in place, performed repeatedly at a challenging tempo for a very short period of time, usually one to two minutes at a time. Exercise snack breaks can then be threaded throughout the day.
Are exercise snacks practical and effective?
In past studies, even a few minutes a day of exercise snacking helped improve people’s fitness, moods and metabolisms, whether they did any other formal exercise or not.
But most of those studies took place in university laboratories, under close supervision and frequently with healthy volunteers, including strapping, young college students.
Those conditions aren’t typical of most people’s lives, which involve work and home commitments and, often, health concerns, including Type 2 diabetes.
It hasn’t been clear whether exercise snacks can be feasible and effective in more real-life situations.
So Little and his colleagues recruited 31 adult men and women with Type 2 diabetes that was well controlled with medications that didn’t include insulin. Most were middle-aged. None exercised regularly.
They gave the volunteers continuous glucose monitors, to track their blood sugar throughout the day, and fitness trackers to check their heart rates.
Then they showed them a few simple exercise snacks.
So many ways to snack on exercise
“There are plenty of ways” to perform exercise snacks, Little said. In this study, they included:
- Marching or running in place
- Step ups (step up and back down on a stair or box as fast as possible, alternating legs)
- Box steps (hurry forward, to the side and backward inside an imaginary six-foot square)
- Speed squats (squat up and down rapidly)
- Jumping jacks
- Side shuffle (with knees bent, take wide steps to one side, then the other)
The researchers asked the volunteers to pick whichever snacks they preferred and complete four of them a day, with each snack lasting one minute. People should aim for a challenging intensity, the researchers said, one that felt like at least a seven on their personal scale of effort from one to 10, and, ideally, each snack should be done within an hour of a meal.
Then the researchers sent people back to their normal lives and didn’t otherwise oversee their routines.
The effects of four minutes of exercise snacks
The volunteers spent two days performing four exercise snacks a day and two days doing no exercise. (The researchers provided them with individualised meals during these times, so people wouldn’t change their diets.)
Then the scientists analysed everyone’s blood sugar control.
It was better on the days they briefly box stepped, marched in place or speed squatted than the days they didn’t. Almost everyone’s blood sugar levels stayed lower during the daylight hours when they exercise snacked, with slighter, shorter after-meal blood-sugar spikes.
The effects, though consistent, were small. But the researchers hadn’t expected substantial improvements, Little said, since the volunteers already controlled their blood sugar well. With the snacking, that control was slightly better.
And almost everyone seemed to find the four minutes of daily exercise tolerable and even, for many, fun.
This study looked only at short-term effects, though, and doesn’t show whether continued exercise snacking would have greater or more-lasting impacts on blood sugar.
It also doesn’t tell us much about the ideal snack serving. “We had to make somewhat arbitrary choices” about the length and number of snacks, Little said. “We don’t think there’s anything magical about precisely one minute of exercise,” or four minutes a day. Seventy seconds at a time might be better. Or five daily snacks. “Find what works for you,” Little said.
Exercise snacks also aren’t meant to supplant regular, sustained exercise, Gibala said. “I would always recommend that people meet the guidelines.”
But if you don’t have the time or inclination to regularly work out and are worried about your blood sugar, he said, consider a minute of stair stepping now and 60 seconds of side shuffles later today. Every minute counts.