The so-called “weekend warrior” exercise approach offers an enticing trade: skip the workouts all week, and cram them into one or two days instead. It sounded great to me, until I realized it could turn my hard-earned “Thank God it’s Friday” into “Oh God, it’s Friday.”
Still, for people who genuinely lack the time to exercise during the workweek, this approach could offer real convenience—and real health benefits.
A recent study in Hong Kong has supported that idea, finding that people who packed all their weekly exercise into one high-intensity interval training (HIIT) session lost about as much body fat as those who spread the same workout across three sessions.
So, is doing all your exercise in one session really just as good as spreading it out? The answer depends on your goals and overall health. But according to Dr. Keith Diaz, an exercise physiologist at Columbia University, even infrequent exercise has real value.
“You don’t have to be a daily gym goer to reap the benefits,” he says. “Some exercise, even if it’s just one time a week, provides health benefits.”
Weighing the evidence
The study, published in Nature Communications, spent 16 weeks following 315 adults who were overweight or had central obesity. The researchers split the participants into three groups, with one doing a single 75-minute HIIT session per week, and another spreading this exercise across three weekly sessions.
“They had participants do three 25-minute HIIT sessions of 4 minutes hard and 3 minutes easy,” Diaz says. “There was 15 to 30 minutes between HIIT sessions, plus a 5-minute warm-up and 5-minute cool-down.” The once-weekly group did all three of those 25-minute blocks in a single visit; the second group spread them into three visits across the week, one block per visit. A third group, the controls, did not exercise, and instead attended health education classes.
By the end of the 16 weeks, both HIIT groups had lost more body fat than the control group. Specifically, the once-weekly group lost about 1.75 pounds more than the control group, and the group that exercised three times a week lost 2.2 pounds more. Waist circumference, which is a measure of central obesity, also improved significantly in both exercise groups compared to control.
“These were relatively modest reductions in fat,” Diaz says. Neither group reported any exercise-related injuries.
The fitness factor
The researchers measured much more than fat loss. They also tracked cardiorespiratory fitness, which is a measure of how efficiently the body uses oxygen during exercise, and a strong predictor of long-term health.
By this measure, the two workout groups did not perform equally. The group that exercised three times a week achieved roughly an 11 percent improvement in cardiorespiratory fitness, compared with an approximate 6 percent improvement in the once-weekly group. Diaz has a theory for why this might be the case.
“Physiologically, the more frequently you stress your body with exercise, the more it will adapt and yield changes to your heart, blood vessels, and muscles,” he says.
So, if fat loss is your main priority, a “weekend warrior” workout might be enough. However, Diaz believes the study actually makes a case for spreading exercise across the week “if your focus is on being fitter and generally being more healthy.”
The ideal weekend warrior
So who does stand to benefit from squeezing a week’s worth of exercise into one session? According to Diaz, the ideal “weekend warrior” is a healthy person who, because of the demands of their daily lives, might not get around to exercising otherwise.
“This approach is best suited for generally healthy individuals who are short on time during the week and struggle to exercise because of their busy weekday schedule,” he says.
However, some people with preexisting health conditions might not see the most benefit from this highly consolidated regimen. In particular, Diaz says people with diabetes or hypertension should try to be physically active every day.
“Exercise lowers blood sugar and blood pressure for 12 to 24 hours afterward,” he says. “So, the weekend warrior approach would not be ideally suitable for individuals with diabetes or hypertension, who need these regular reductions in blood sugar or blood pressure.” Diaz adds that people with heart conditions should discuss once-weekly HIIT with their doctors before starting.
Related ‘Ask Us Anything’ Stories
The bottom line
Although the once-weekly approach has undeniable appeal and might truly benefit some busy folks, Diaz notes that it’s not exactly the magical quick fix some headlines would suggest.
“I think the headlines around one day of exercise a week melting belly fat are misleading,” he says. “Yes, it’s one day of exercise, but it’s a lot in one day.”
Although the exercise itself takes 75 minutes in total, adding time to warm up and rest between the sessions means that the single weekly workout takes almost three hours to complete. And it’s not melting the fat away.
Despite that deflating reality check, Diaz sees real potential in this approach when healthy people use it appropriately.
“This study adds further support that some exercise, even if just on the weekend, is better than none,” he says. “So if the weekend is the only time you have to exercise, this could be an option for you.”
In Ask Us Anything, Popular Science answers your most outlandish, mind-burning questions, from the everyday things you’ve always wondered to the bizarre things you never thought to ask. Have something you’ve always wanted to know? Ask us.
The post Can one intense workout per week keep you healthy? Here’s the science. appeared first on Popular Science.