When it comes to physical activity, every bit counts

We’ve stepped into a new year, which for many people means new resolutions. And this story was supposed to tackle a big one: the best exercise people can do to be healthy.

There’s just one small problem. “There’s simply no such thing as ‘best exercise,’” says Emmanuel Stamatakis, a physical activity epidemiologist at the University of Sydney. If you see a headline like that, he says, it’s probably clickbait.

What scientists do know — from piles of studies spanning 70 years — is that regular physical activity pays off in long-term health benefits. And recent work is starting to paint a clearer picture of all the activities that can help. You don’t have to body build like Arnold Schwarzenegger or crush marathons like Tigst Assefa. And not everyone has the time, money or ability to join a gym or use special equipment. But you don’t need to, Stamatakis says. Biking to the grocery store, raking leaves, playing soccer with your kids — it all counts.

Scientists still have much to figure out, like how physical activity’s benefits cascade through the body and how to empower people to add movement to their daily lives. But at least one conclusion seems clear, says I-Min Lee, an epidemiologist at Harvard Medical School and Brigham and Women’s Hospital in Boston. “Any physical activity is better than none.”

For Lee, it comes down to finding something you enjoy. That can make the difference between getting off the couch or staying put. “The best physical activity,” she says, “is something that you will do and stick with.”

Physical activity can extend your life and offer a slew of other health benefits

The idea that physical activity is good for you might seem eye-rollingly obvious and peskily pervasive. Fitness influencers post workouts on social media, news reports tout exercise’s benefits and governments worldwide try to get citizens moving.

Still, the United States’ current physical activity guidelines, published in 2018, reported that some 80 percent of adults aren’t doing enough. Adults need at least 150 minutes of moderate physical activity or 75 minutes of vigorous activity per week, plus muscle-strengthening activities at least two days per week, the guidelines suggest. (How long should these muscle-strengthening sessions last? “We don’t really know,” Lee says.)

But scientists are learning that even a little physical activity can be helpful, Lee says. Most of the studies underpinning the 2018 recommendations relied on self-reported data, Lee and colleagues wrote in a JAMA opinion piece in October. People tend to remember exercises like running or swimming laps, Lee says. But the myriad movements we take in a typical day — movements that scientists now know can improve health — were difficult to document via self-reports.

Today, wearable technology has yanked those missing movements out of obscurity and into the spotlight. Outfitting participants with tracking devices lets scientists collect mountains of in-depth data throughout a person’s day, such as step count, acceleration and heart rate. That’s helping reveal all the things that physical activity (or the lack of it) can do for people’s health.

“If you do nothing, just do a little bit. If you already do a little bit, do a little bit more.”

I-Min Lee

In the last year, scientists have shown people who did more physical activity were less likely to be hospitalized for common conditions like gallbladder disease, diabetes and urinary tract infections. These data add to recent survey-based studies and clinical trials linking exercise with lower risk of death due to flu and pneumonia, improvements in memory and attention, and better outcomes after a COVID-19 infection.

“Study after study has demonstrated the benefit of physical activity,” says Bryant Webber, a preventative medicine physician at the U.S. Air Force Academy in Colorado Springs, Colo. His team has shown that it’s never too late to start. In a study of more than 100,000 people age 65 and older, both aerobic training and muscle strengthening seemed to lower the risk of dying over the next eight years. Even people older than 85 saw benefits, says Webber, who did the work while at the U.S. Centers for Disease Control and Prevention. “We were impressed.” 

Some people may be getting the benefits of physical activity without realizing it. Stamatakis’ team in Australia studies incidental activity: the typical, routine movements people perform in their daily lives. His team analyzed data from people who don’t exercise in their free time but had worn tracking devices for a week. Just a minute or two of intense activity — like taking the stairs or dashing to catch a train — a few times per day reduced the risk of dying in the following seven or so years by about 40 percent, Stamatakis and colleagues reported in 2022 (SN: 12/8/22). The more activity, the better, he says. And last year, his team linked just three and a half minutes of daily vigorous activity with a roughly 18 percent reduction in cancer risk.

Walk uphill, carry a heavy grocery basket, “get a little bit out of breath,” Stamatakis says. Any burst of exertion that briefly boosts your heart rate a few times per day could have long term health benefits, he says. That’s something many people don’t understand. In interviews with middle-aged people, Stamatakis has heard a common misconception. “The majority of them still think that you need to go to the gym, otherwise there’s no point.”

Don’t get him wrong, Stamatakis isn’t saying people should skip the gym. “I want to make it absolutely clear that exercise is a fantastic option,” he says. But for people who can’t afford a gym membership or aren’t able or willing to exercise in traditional ways, short bursts of vigorous activities several times per day could be good, too.

Scientists still have questions about exercise, but they know even a little bit helps

At Harvard, Lee has worked to dispel another popular misconception: that people need to take 10,000 steps every day to stay healthy.

She started looking into the idea in 2018, when her hospital launched a campaign to get employees to walk more. Because Lee studies physical activity, her administrators asked her to form a team. It was mostly middle-aged and older folks, she says. “For some of these people, if you’re asking them to do 10,000 steps — I mean, no way,” she says. “Even doing 5,000 steps is a stretch.”

In 2019, Lee’s team found that older women who took around 8,500 steps per day were 66 percent less likely to die during the study than those who took roughly 2,500 steps per day. In a 2022 analysis, Lee and her colleagues reported something similar in men and women of different ages. Bottom line: For mortality benefits, people age 60 or older should shoot for 7,000 steps a day, and people younger should shoot for 9,000, she says.

But those targets shouldn’t be discouraging, she says. Lee takes a tiered approach. “If you do nothing, just do a little bit,” she says. “If you already do a little bit, do a little bit more.”

She follows that advice herself. Lee grew up in the tropics in Malaysia, where it was hot, and she didn’t see many people exercising, including herself. “I did diddly-squat,” she laughs. That changed after she came to the United States for her doctorate. “It got to be so embarrassing to do physical activity research without being physically active,” she says. So she started running. “I run slowly, and I don’t run a lot, but I do it,” she says.

The message that people can reap health benefits from even a little bit of physical activity is seeping into the mainstream, says Lyndon Joseph, an exercise physiologist at the National Institute on Aging in Bethesda, Md. “You don’t have to be able to sprint like Usain Bolt,” he says. “You just need to be active.”

Scientists know physical activity works, Joseph says, though they don’t fully understand how. Why does walking, for example, which relies on leg muscles, also help the heart, lungs, kidneys and immune system? “The whole body responds to exercise,” Joseph says. Scientists are trying to figure out the molecules at play, and how those released from one tissue can improve the health of another. “That is the big question.”

How to get people to move — and do it consistently — is another big question. Changing people’s behavior is no easy feat, Stamatakis says. And massive structural barriers often stand in the way. Even if scientists get people on board with upping their step counts, if their neighborhoods don’t have sidewalks, hitting daily step goals becomes a lot more difficult.

More sidewalks, trails and bike paths would make it easier for people to rack up incidental physical activity. “The role of the environment is critical,” Stamatakis says. Lee agrees. Physical activity is not simply a personal choice, she says. Government policies can influence how much or little we’re able to do. Again, she emphasizes, it doesn’t take much to get substantial health benefits (SN: 11/5/19). And people can start at any level.

In fact, Lee says, “the biggest bang for your buck actually comes among people who go from doing nothing to doing just a little bit.”