Extending the length of your daily walks can benefit your heart, new research suggests.
In a study conducted among healthy adults, people who accumulated most of their daily steps in bouts of 15 minutes or longer had significantly lower risks of heart disease and death nearly a decade later than those who got in several shorter walks throughout the day. The study was published Monday in the Annals of Internal Medicine.
What’s more, adults who had been less active in the past and went on longer walks showed the greatest health gains.
An international team of scientists looked at the daily movements of 33,560 adults aged 62 on average and living in the U.K., using information collected from 2013 through 2015 in a medical research database called the UK Biobank. For three to seven days, participants wore an accelerometer on their wrist that recorded their physical activity.
Researchers divided the people into four groups, based on how they logged most of their steps each day: in bouts shorter than five minutes, five to less than 10 minutes, 10 to less than 15 minutes and 15 minutes or longer. The largest group — 42.9% of participants — fell into the under-five-minute category.
After about 9½ years of follow up, the researchers found that people who had walked in spurts of 15 minutes or longer had the lowest likelihood of dying during the study period, while people who took walks shorter than five minutes had the highest risk.
People who walked in longer bouts also had lower risks of heart disease during the follow-up period, with risk increasing as walk duration shortened.
Co-lead study author Borja del Pozo Cruz, a professor and researcher in the department of sports sciences at Universidad Europea de Madrid, calls the four walk durations “doses.”
“There’s a clear dose response,” del Pozo Cruz said. “The longer the bout, the better it is for the different health outcomes that we analyzed.”
The decision to study people’s health via step accumulation patterns, as opposed to total number of steps or intensity of physical activity, was intentional, he said.
“It’s easy to translate; everyone understands steps,” del Pozo Cruz said. “Everyone can essentially measure steps with their smartwatches or smartphones or pedometers or whatever. We thought focusing on steps would be much more impactful because their translation is immediate.”
Forget ‘exercise snacks’ and 10,000 steps a day
The notion that adults should strive for 10,000 steps a day is more a marketing ploy to sell fitness trackers than a scientific guideline, according to Steven Riechman, a professor in the department of kinesiology and sport management at Texas A&M University, who wasn’t involved in the study.
Riechman said that the body goes through a number of adaptations as it shifts from rest mode to exercise mode — changes that take a bit of time. That could explain why people who walked in bouts shorter than five minutes didn’t see as strong health gains, he said.
“You need to get all the systems engaged and fully operational, and that’s where the health benefits come from,” Riechman said. “The one I particularly thought of, [which] the article did not mention, is that the increase in body temperature is probably not going to occur in less than five minutes of walking.”
Despite mixed research on the health benefits of 10,000 steps a day, the study considered people who achieved an average daily step count under 8,000 to be “suboptimally active.” All study participants logged fewer than 8,000 steps a day, and those who logged fewer than 5,000 were deemed sedentary. The median activity of all participants was 5,165 steps a day.
The link between longer walking bouts and lower risks of early death and heart disease was more notable among sedentary participants, researchers found. Within this group, people who walked in bouts shorter than five minutes had a 5.13% risk of death during the study period, compared to a 0.86% risk for people who walked in bouts exceeding 15 minutes. Their risk of developing heart disease during the decade-long study period was 15.39% and 6.89%, respectively.
“You have big returns from zero to something,” Riechman said. “Then you keep getting benefits, but they’re just lower and lower. By the time you get to 10,000 [steps], you’re not accumulating too many more benefits.”
The study is at odds with previous research that touts the merits of “exercise snacks,” or spurts of physical activity lasting less than five minutes. For instance, a study published earlier this month in the British Journal of Sports Medicine found that exercise snacks improved the fitness levels of physically inactive adults. However, that study defined short spurts as structured, moderate-to-vigorous activity. The short spurts in del Pozo Cruz’s study, on the other hand, included the unstructured, low-intensity steps one might accumulate throughout the course of the day.
“Every step counts,” according to the American Heart Association, a mantra Riechman supports. Some physical activity is always better than none.
“Getting out and getting some of the steps, for sure, there’s definitely a benefit,” he said. “To me, you’re just not optimizing the benefits.”
‘Never too late’ to start walking
The study had several limitations, including that 97% of participants were white.
Another research constraint is that participants’ walking patterns represent a snapshot in time, and people’s exercise habits may fluctuate over the years. Even so, the study’s large sample size likely stabilized such variation, said Carmen Swain, director of the health and exercise science program at the Ohio State University, who wasn’t involved in the research.
One of the study’s biggest strengths, she said, is participants’ average age: 62. It’s a time of life when people may assume they’re past the point of lowering their risk of heart disease and early death.
“You can start [walking] at any age; it’s not too late,” Swain said. “The physiological adaptations that occur for a 20-year-old are also going to happen for a 60-year-old.”
Yes, a 60-year-old may already bear underlying signs of heart disease, she said, which is why it’s even more important for older adults to maintain a walking regimen.
“Unfortunately, it’s often a challenge for this population to start because they haven’t done it for so long,” said Swain, who lectures her students on the power of walking. “There has to be motivation.”
With heart disease being the No. 1 killer of men and women in the U.S., Swain hopes the heart-health benefits of walking will be motivation enough.
“Walking is so democratic. You can just do it wherever you want, whenever you want, however you want,” she said. “It’s a good form of exercise.”