Fitness face-off – Harvard Health

What’s in style? The question doesn’t just relate to fashion. Indeed, even exercise styles go in and out of vogue, echoing trends fueled by social media and other cultural drivers.

Case in point: high-intensity bursts of exercise have grabbed headlines over the past couple of years, with scientists generating an array of studies examining the health benefits of short spurts of movement lasting from one to three minutes. That might consist of jumping jacks, lunges, running in place, jumping rope, air boxing, running up stairs, or any other high-intensity activity.

Meanwhile, plenty of research continues to focus on the health advantages of moderate-intensity, continuous movement. Mainstay choices for these sessions include brisk walking, cycling, jogging, and elliptical and treadmill use.

Given the swings in popularity between the differently paced alternatives, perhaps the most pressing question is which one is better for us. It might seem certain exercise patterns might prove superior to others, but we should resist the temptation to believe that, says Dr. Meagan Wasfy, a sports cardiologist at Harvard-affiliated Massachusetts General Hospital.

“There are always trends, and each one claims to be the latest and best way to move your body,” Dr. Wasfy says.

Breaking down the data

What health benefits does each approach offer? A sampling of recent studies and official health guidance weighs in.

Evidence supporting exercise bursts includes the following:

• A 2022 analysis of data collected on more than 25,200 people who didn’t otherwise exercise (average age 62, 56% women) published in Nature Medicine found that those who routinely did brief bursts of vigorous activity — defined as three bouts, each lasting a minute or two — had significantly lower odds of dying or developing cardiovascular disease over the following seven years than participants who didn’t.
• A 2023 analysis in JAMA Oncology of more than 22,000 people who didn’t exercise (average age 62, 55% women) suggested that even short, intermittent periods of intense movement — a minute at a time, three or four times a day — was linked with 18% lower cancer risk over the following 6.7 years, especially for cancers of the breast, uterus, or colon.

Evidence supporting longer, moderate-intensity exercise includes the following:

• Adults who do any amount of moderate-to-vigorous exercise derive health benefits, including reducing their risks of cardiovascular disease, diabetes, and some forms of cancer, according to the CDC.
• A 2022 analysis in JAMA Internal Medicine involving 78,000 people (average age 61, 55% women) found their risk of heart disease, cancer, and premature death dropped by 10% over the following seven years for every 2,000 steps they logged each day, with the benefit peaking at 10,000 steps.

Sense a theme from the findings? Regardless of intensity, it’s apparent that any movement is good for your health.

“No one comes out ahead with regards to the long-term outcomes,” Dr. Wasfy says. “What matters most is moving your body and doing more of it. The sum of movement, over the course of a year or decades of your life, is what matters.”

Exercise caveats

One clear advantage to exercise bursts — or its cousin, high-intensity interval training (HIIT) — is that any high-intensity activity enables you to fulfill recommended exercise guidelines in less time. Health organizations advise adults to get at least 150 minutes of moderate exercise or 75 minutes of vigorous exercise (or some equivalent combination of the two) per week. For an HIIT workout, you alternate vigorous, short sprints with brief periods of rest or lower-intensity movement.

“It’s a time-efficient way to get your recommended exercise dose in less time,” Dr. Wasfy says.

High-intensity exercise does pose a few drawbacks, however. These include a greater risk of injuries and inflammation to joints and muscles. Additionally, for people with heart disease or its risk factors, sudden bursts of exercise could be more likely to bring on new cardiac symptoms.

“If you’re writing an exercise prescription not knowing anything about someone’s health history, you’d write it for moderate-intensity, continuous exercise,” Dr. Wasfy says.

If you’d like to increase your exercise intensity but have existing heart disease — or symptoms such as chest pain with vigorous movement — talk to your doctor in advance. Older adults who’ve noticed their ability to exercise has declined should also speak up.

Ultimately, Dr. Wasfy says, you should choose a style of exercise you really like — and will do consistently — and disregard fitness trends. “If you’re healthy,” she says, “it’s really your choice.”

Image: © Luis Alvarez/Getty Images