July 19, 2023 — It’s well known that exercise is beneficial to one’s health and particularly that it protects against heart disease. But how much exercise should people get? And how should they apportion their exercise time?
Current guidelines (such as those from the World Health Organization and the American Heart Association) recommend at least 150 minutes (2.5 hours) of moderate-to-vigorous exercise weekly to lower the risk of cardiovascular disease and death, but these guidelines don’t specify how those hours should be divided up. The U.K. National Health Service recommends spreading the exercise evenly over 4 to 5 days, or doing some every day.
The question is whether exercise is just as helpful if it’s concentrated over 1 or 2 days — sometimes called a “weekend warrior” pattern because many people who can’t exercise during the busy workweek can make the time to do so on the weekend.
A new study has encouraging news for weekend warriors: It’s the amount of exercise, not the pattern of exercise, that counts, even if the workouts aren’t evenly distributed over the week.
Improving Cardiovascular Risk
Lead study author Shaan Khurshid, MD, MPH, instructor of medicine at Massachusetts General Hospital in Boston, shared the researchers’ motivation for conducting the study.
“The weekend warrior pattern has been studied previously, but typically relying on self-reported data, which may be biased, or too small to look at specific cardiovascular outcomes,” Khurshid said. The researchers wanted a more objective measure of how much exercise individuals were actually getting and also wanted to investigate the question in a much larger sample.
To do so, they studied 89,573 participants in the U.K. Biobank, a huge biomedical database and research resource that has in-depth genetic and health information from half a million U.K. residents.
The average age of the participants was 62, and a little over half were female. For 1 week, participants wore a device on their wrist that recorded their total physical activity, as well as the amount of time spent at different levels of exercise intensity.
The researchers compared three exercise patterns:
- Active-weekend warrior (at least 150 minutes of mild-to-moderate physical activity, with the total amount of exercise over 1 to 2 days)
- Active-regular (the same amount of exercise, but spread over more time)
- Inactive (less than 150 minutes).
“We saw the opportunity to leverage the largest sample of measured activity to date in order to more definitively address the question of whether activity pattern affects specific major cardiovascular diseases differently,” Khurshid said.
Participants were followed for a median of 6.3 years to see if they had developed one of four types of heart problems: atrial fibrillation, heart attack, heart failure, and stroke.
A little over a third of participants (33.7%) were classified as inactive, while close to a fifth (24%) were active-regular. The largest percentage (42.2%) was active-weekend warriors.
After adjusting for other factors that can affect the risk of developing heart problems (such as age, sex, racial/ethnic background, tobacco use, and self-reported health and diet quality), the researchers found that both exercise patterns were associated with a lower risk of developing these conditions:
- Heart attack: 25% lower for active-weekend warriors, 35% lower for active-regular
- Heart failure: 38% lower for active-weekend warriors, 36% lower for active-regular
- Atrial fibrillation: 22% lower for active-weekend warriors, 19% lower for active-regular
- Stroke: 21% lower for active-weekend warriors, 17% lower for active regular
“The take-home is that efforts to optimize activity, even if concentrated within just a day or 2 each week, should be expected to result in improved cardiovascular risk profiles,” Khurshid said.
Maintaining Good Habits
Pinchas King, a 53-year-old publisher from Passaic, NJ, exercises on a regular basis.
“I try to exercise every day by going on a treadmill, and I start with high-intensity exercise,” he said.
King exercises for many reasons. “It gives me ongoing energy and also has multiple health benefits, such as preventing cancer, heart disease, and neurodegenerative diseases such as Parkinson’s,” he said.
He considers himself fortunate to be able to include exercise in a regular routine but is aware that many people aren’t able to do so. “The results of this study sound good and for those people who don’t have time during the week [to exercise], the study is useful,” he said.
But he expressed concern that people who already have an exercise regimen spread over the course of the week “might give up that good habit and postpone exercise until the weekend, and then maybe not end up doing it at all or doing less than the recommended amount.”
King considers the “2-day option” as a “nice substitute when necessary” — for example, if you’ve been sick or have been particularly busy and were unable to exercise on a given week. “But I think it’s better that people find time to incorporate exercise into their daily lives because waiting until the weekend might make it harder to implement.”
‘Every Minute Counts’
According to the CDC, only 28% of U.S. adults get the amount of exercise recommended by the guidelines.
One reason many people don’t exercise enough is that their busy schedule may not allow them time. Peter Katzmarzyk, PhD, associate executive director for population and public health sciences at the Pennington Biomedical Research Center in Baton Rouge, LA, said the study findings are encouraging for people in this situation.
“These results are important as they point out that physical activity can be accumulated throughout the week in different ways, which opens up more options for busy people to get their physical activity in,” said Katzmarzyk, co-author of an accompanying editorial in which he writes, “every minute counts” — especially among the three-quarters of U.S. adults who don’t achieve the recommended exercise goal.
Khurshid agrees. “Patients should be encouraged to achieve recommended activity levels and should not be discouraged if, for whatever reasons, they are only able to focus exercise within only 1 or a few days of the week,” he said. “Instead, our findings suggest that it is the volume of activity, rather than the pattern, that matters most.”
