Study: Just 30 Minutes Of High-Intensity Exercise Weekly Provides Health Benefits

In a busy world with work demands, family obligations and seemingly endless to-do lists, it can be hard to find any time to exercise — let alone hit the (fairly intimidating) recommended amount per week.

Less than 25% of Americans meet the country’s physical activity guidelines, which state that adults should get at least 150 minutes of moderate-intensity exercise (such as brisk walking, gardening, doubles tennis) each week or 75 minutes of vigorous-intensity exercise (such as running, swimming laps or hiking uphill) and do at least two days of strength training each week.

But new research out of Norwegian University of Science and Technology suggests you may not need to exercise that much to see health benefits — that is, if you’re working out hard. Researchers found that just 30 minutes of high-intensity exercise per week (yes, per week) is good for your health, specifically heart health.

Researchers said it’s best to split the 30 minutes of weekly exercise up across the week for maximum benefit, so 7.5 minutes of vigorous exercise four times a week, for example. Exercise benefits, such as blood pressure and blood sugar control, happen for one to two days after exercise, according to researchers, making it best to exercise several times throughout the week.

According to the study, this high-intensity exercise needs to be heart-pumping and leave you breathless; a low-intensity yoga class or leisurely neighborhood walk doesn’t fit the bill.

“Hard activity for someone who’s inactive, it feels like a lot and it can be pretty tough,” said Dr. Jason Tso, a cardiologist and medical director of the Sports Cardiology Program at Stanford University School of Medicine in California. Tso is not affiliated with this study.

Researchers categorized high-intensity exercise as a workout that gets your heart rate to at least 85% of its maximum or movement that you can’t talk through comfortably but does allow you to speak in short sentences. This often includes activities like a spin class, running or singles tennis.

But exactly what gets you to the point of breathlessness depends on your fitness level. For some people, it is a fast trail run, while for others, it’s a slow jog.

“Vigorous activity places real demand on the heart,” Dr. Sawalla Guseh, the director of the Cardiovascular Performance Program in the Mass General Brigham Heart and Vascular Institute, told HuffPost via email. Guseh is not affiliated with this study.

“For someone who has been inactive, or who has risk factors such as high blood pressure, diabetes, high cholesterol, smoking history, symptoms, or a family history of heart disease, it is wise to check in with a clinician before abruptly starting intense exercise,” Guseh added.

Now, 30 minutes of exercise per week is much less than the 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity exercise that’s recommended in this country’s official guidelines.

The recommendation of 150 minutes of moderate-intensity exercise each week is based on large-scale population studies, according to Tso. But there is a reason the recommended time for vigorous exercise is lower.

“There’s actually been a fair amount of work looking at shorter but very high-intensity exercise showing similar benefit to cardiovascular health,” Tso said. “I think what all this really indicates is that just doing something, even small amounts, gets you a ton of benefit.”

“For a sedentary person, even small amounts of vigorous activity may improve cardiovascular fitness and cardiovascular risk factors,” added Guseh.

“Higher-intensity exercise is more time efficient in that you do burn more calories, and you probably get more bang for the buck at lower amounts of time,” Tso continued. But high-intensity exercise is challenging and isn’t the right fit for everyone. “So, there’s some trade-off there,” Tso said.

Before you commit to a five-minute daily workout regimen, know that it may not be as beneficial as longer workouts.

“I would not present 30 minutes per week as the final goal. The broader evidence supports a dose-response relationship: More regular physical activity generally provides greater cardiovascular benefit, up to a point,” said Guseh.

According to Tso, “I think it’s better to say five minutes a day of vigorous activity is much better ― immeasurably better ― than nothing. But is that enough? That’s a big question mark.”

More research that compares the benefits of short amounts of high-intensity exercise to the benefits of longer amounts of physical activity is needed. “I wouldn’t anchor on this one study, but it’s good anyway. It just reinforced the concept that everyone should be doing something,” Tso said.

“I’d be cautious about saying this settles the science,” said Guseh, who pointed out a potential limitation in the research.

“People who can do vigorous exercise are often healthier and fitter to begin with. They may have fewer symptoms, less unrecognized cardiovascular disease and fewer physical limitations,” Guseh added.

Regular exercise provides countless health benefits.

“It changes the heart and the vascular system. It lowers blood pressure, lowers cholesterol, actually increases heart size — it really allows you to have more energy and be able to function better in daily life,” Tso explained.

It also benefits your mood. Exercise is shown to lower anxiety and depression symptoms. Exercise is good for your bone strength, reduces the risk of certain cancers, is an important way to maintain muscle and helps you sleep better.

“Doctors prescribe medicines all the time, but exercise is probably as effective as several medicines,” Tso said.

Exercise should be part of everyone’s lifestyle, he added. Just because you can’t commit to multiple hours of exercise each week doesn’t mean you shouldn’t work out at all.

“Everyone can stay as active as they can, or try to make some time to stay active,” Tso said.

Lots of people like to focus on doing the “best” workout for the “most optimal” amount of time, which can end up being a barrier to exercise. If you only have time for a 10-minute walk today, get out and do it. It’s infinitely better than sitting on your butt.

“For the general population … just do something and get started and do it regularly, which I think is probably reinforced by this paper,” Tso said.

“Thirty minutes is a meaningful starting point, not necessarily the destination,” said Guseh. “Start where you are, build gradually, know your risk and make the goal a sustainable exercise habit.”