There are a million and three ways to exercise. Each one has its respective benefits. Some philosophies subscribe to high-intensity interval training (HIIT), where it’s all about doing maximum output for short bursts of time. Others prioritize endurance at a steady pace. Similarly, some research suggests daily exercise is best, while other studies show it's okay to get it all done on the weekend.
Which one is right? Science doesn’t have a definitive answer. And a recent study published last week in the Scandinavian Journal of Medicine and Science in Sports adds more credence to daily exercise: The new study offers evidence that exercise frequency tops exercise duration. The study suggests that moderate exercise several times a week does more than longer or more intense exercise only once a week.
However, this finding appears to contradict a previous study and longevity hack that found so-called weekend warriors, or those who only exercise once or twice weekly on weekends, derive similar benefits to those who exercise more frequently.
The twist, perhaps unsurprisingly, is that they’re both right.
Science in action — In the recent study on frequent exercise, 34 healthy adults comprised three groups with different four-week exercise regimens:
- One cohort performed six bicep curls with a weight one day a week
- Another performed six curls per day five days a week
- The third performed 30 curls one day a week
The researchers, who are from Japan and Australia, concluded that performing fewer reps per day but more days per week was more effective than performing a large number of reps one day a week. Looking at the 2020 World Health Organization (WHO) weekly exercise guidelines, which suggest a weekly quota of 2.5 to 3.5 hours of moderate exercise, this finding may reasonably be interpreted as a point for spreading out several hours of exercise over the week, rather than completing it all at once. Furthermore, the WHO also recommends strength exercises at least two days a week.
In the evidently contrasting study, researchers from eight countries examined the self-reported exercise habits of 350,978 healthy Americans aged 18 to 84 between the years 1997 and 2013, all marked in the U.S. National Health Interview Survey. Then, they linked participant records with the National Death Index through the end of 2015 to follow mortality. These researchers found that those who reported exercising only on the weekend had similarly low mortality rates to those who exercised throughout the week.
Why it’s a hack — The truth is they’re both good for different things, and even doing just one can do wonders.
Jeffrey Hsu, a cardiologist at the University of California, Los Angeles, points out that for one thing, these studies follow different outcomes. While this more recent study looks at muscle thickness and strength over only four weeks in three dozen people, the weekend warrior one follows the risk of death in hundreds of thousands of individuals over decades.
“Overall, they don’t contradict each other,” Hsu tells Inverse. “I think they have a similar theme ... but very importantly, they’re looking at very different outcomes.” Hsu was not involved in either study.
Additionally, the long-term study counts anything as exercise, whereas the recent study only looked at a particular bicep curl. Both are integral to healthy living and aging, but can’t necessarily be assessed the same way. As a heart doctor, Hsu has more experience with cardiovascular workouts as a backbone of physical health. “What we have a lot more data for is cardiovascular exercise,” he says, clarifying that there’s a strong link between regular cardio exercise and longevity as well as improved life quality.
While the weekend warrior study found no significant mortality difference between weekend warriors and more regular gym goers, the more recent study did find a clear beneficiary. The group who practiced six reps per day for five days a week showed the most strength growth, even more than the group who did the same number of reps per week but performed them all in one day.
Exercise and sports science professor Kazunori Nosaka, a co-author of the strength training paper, says that his team’s recent study doesn’t yet have data on how these habits affect heart health, though they’re investigating it. He does give a shoutout to HIIT as a way to improve both strength and cardiovascular wellness. Nosaka works at Edith Cowan University in Joondalup, Australia.
That’s not to say weight training is irrelevant to longevity — quite the opposite. It just may be more difficult to show a direct link between lifting and longevity. Hsu says that such data may be “harder to capture” in long-term studies. But you don’t need a longitudinal study to see that weight training benefits us in the long run. “If you think about what the benefits are with weight training, especially as we get in our 70s, 80s, and 90s, we know that more frequent causes of death in these populations are related to muscle weakness and poor balance,” Hsu says. As we get older, falls become more dangerous because we’re more prone to serious bone fractures. Growing our muscles helps safeguard our balance and strength to prevent these falls.
Hsu also underscores that since this recent study is smaller and drew on less data, there’s less information on how socioeconomics may affect exercise habits. For instance, there’s a question of what circumstances make a weekend warrior lifestyle more viable than daily exercise.
How it affects longevity — In an answer that may be equal parts frustrating and liberating, what’s best is getting any exercise, period.
“My general philosophy is whatever is a regular habit,” Hsu says. Still, he’s ultimately wary of the weekend warrior routine. “The cardiovascular system doesn’t like this whole stop-and-go mentality where it’s not being worked six days a week, then on one day a week, it’s getting worked to its maximal intensity.” While it doesn’t work super well for the heart and lungs, Hsu says it poses a “very, very, very low” risk to cardiovascular health.
Nosaka reinforces that his team’s paper finds that frequent exercisers got the most out of what they did, but the best kind of exercise is the one that gets done. Even the six-rep bicep curl set took only one minute, and, as he writes to Inverse, “Every muscle contraction counts!”
Hack score out of 10 — 🏊🏿♂️🚶🏿♀🚶🏻🏃🏼🏃🏼🚴🏼🏊🏿♂️🚶🏻🏃🏼 (9/10 regular exercisers and weekend warriors)