If you don’t have time to exercise during the week, longer workouts over the weekend may be as good for the heart.
Adults should get 150 minutes of moderate to vigorous activity per week, most guidelines recommend, with the typical advice to spread it out through the week. Harvard researchers were surprised to find that people who jammed their 2.5 hours of activity into one or two days cut their risk of heart attack by 27%, compared to 35% among people who exercised more days of the week. "Weekend warriors" also saw heart failure risk drop by 38%, compared to 36% among regular exercisers, the new study published Tuesday in JAMA found.
“The idea that you could cram it all into a weekend or two days a week was a little surprising,” study co-author Dr. Patrick Ellinor, acting chief of cardiology at Massachusetts General Hospital and a professor of medicine at the Harvard Medical School, said.
The bottom line, Ellinor said, is that “getting 150 minutes of moderate to vigorous activity a week is the goal, however you get there.”
To take a closer look at how the timing of exercise made a difference, researchers turned to the UK Biobank, a widely used database of 502,629 participants, ages 40 to 69, who were enrolled between 2006 and 2010. For the new research, a subset of the group agreed to wear wrist-mounted accelerometers, which measure physical activity 24 hours a day.
Ellinor and his colleagues focused on 89,573 of the participants who wore the accelerometers for a week, the majority of whom were followed for 6.3 years. The researchers characterized the participants as either weekend warriors, regular exercisers or as inactive.
A major limitation of the study is that the activity data was collected over just a week, Ellinor said, so they don't know whether the participants continued the same exercise pattern through the follow-up period.
Still, the main message is that people should get 150 minutes of moderate to vigorous activity each week, “however they can get it,” said Dr. John McPherson, a cardiologist and professor of medicine at the Vanderbilt University Medical Center in Nashville.
“It can be bunched into two days or it can be 25 to 30 minutes every day,” said McPherson, who was not involved with the new research. ”What’s really important is maintaining the 150 minutes a week.”
How to avoid injuries from exercising
One argument against compressing exercise into two days is the higher likelihood of injury reported in some studies of weekend warriors. But experts say that people who are careful to build up to an exercise program and who properly warm up and cool down can avoid such injuries.
If you’re going to cram all your exercise into two days, you really need to build up to it, said Keith Diaz, an exercise physiologist and an associate professor of behavioral medicine a the Columbia University Vagelos College of Physicians and Surgeons.
“The biggest concern is overuse injuries,” said Diaz, who was not involved in the new research. “You can’t go from zero to 60 in two days. There are plenty of weekend warriors with no injuries but their bodies have acclimated to it.
The type of activity you pick is also important, Diaz said. While you’ll want to pick something you like to do, low impact activities, like swimming and biking, are a better choice because they’re less likely to damage joints, he added.
Because adult body starts to lose condition after three days of inactivity, limiting workouts to the weekend won't be the path to peak physical performance, Diaz said.
"You’re constantly fighting the body’s tendency to go back to the disuse state,” he explained.
The new study offers good news, said Glenn Gaesser, a professor of exercise physiology in the College of Health Solutions at Arizona State University.
“It really didn’t matter how people sliced up exercise during the week so long as they got at least the minimum amount of moderate to vigorous activity,” said Gaesser.
For people concerned that only exercising one or two days week might raise risk of injury, previous research shows that's mostly from contact sports, said Gaesser, who was not involved with the new research.
Calling the people in the study “weekend warriors is somewhat misleading since most are not doing ‘warrior’ activities,” said Gaesser. “The vast majority are doing typical cardiovascular activities, such as walking, cycling and so forth. Those who are participating in contact games are more likely to get injured.”
To avoid injuries from long workouts, pay attention to what your body is telling you, said Dr. Gregory Katz, a cardiologist at NYU Langone Heart and an assistant professor of medicine at the NYU Grossman School of Medicine.
“Don’t ignore that nagging ache,” said Katz, who was not involved with the new study. “Does this feel like the type of strain you should be putting on your body or something that might be harmful?”