New research says 30 minutes of exercise each week is all you need, but there’s a catch.

It can be hard to find that in a busy world of work demands, family obligations, and a seemingly never-ending to-do list. Any Make more time to exercise — not to mention hit the (rather scary) recommended amount per week.

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

But new research from the Norwegian University of Science and Technology suggests that you may not need to exercise that much to reap the health benefits, that is, if you’re diligent about it. Researchers have found that just 30 minutes of high-intensity exercise (yes, once a week) per week is good for your health, especially your heart health.

Researchers say that for maximum benefit, it’s best to break up your weekly exercise into 30 minutes of exercise over the course of the week, for example 7.5 minutes of vigorous exercise four times a week. Researchers say the benefits of exercise, such as controlling blood pressure and blood sugar levels, are felt within a day or two after exercise, so it’s best to exercise several times a week.

Research shows that this high-intensity exercise should get your heart pumping and leave you short of breath. Low-intensity yoga classes or leisurely walks around the neighborhood are not suitable.

“For people who are inactive, strenuous activity can seem overwhelming and can be quite challenging,” said Dr. Jason Tso, a cardiologist and medical director of the sports cardiology program at Stanford University School of Medicine in California. Mr. Tso is not affiliated with this study.

The researchers classified high-intensity exercise as exercise that causes your heart rate to reach at least 85% of your maximum, or that you can’t comfortably continue talking but can still speak in short sentences. This often includes activities such as spin classes, running, and singles tennis.

But what exactly causes shortness of breath depends on your fitness level. For some it’s a fast trail run, for others it’s a slow jog.

“Vigorous activity puts real demands on the heart,” Dr. Sawalah Guse, director of the Cardiovascular Performance Program at the Massachusetts General Brigham Heart and Vascular Institute, told HuffPost via email. Mr. Guse was not affiliated with this study.

“People who have never been active or who have risk factors such as high blood pressure, diabetes, high cholesterol, smoking history, symptoms, or family history of heart disease are wise to consult a clinician before suddenly starting strenuous exercise,” Gusse added.

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

Tso said the recommendation for 150 minutes of moderate-intensity exercise each week is based on large-scale population studies. However, there is a reason why the recommended time for intense exercise is shorter than this.

“In fact, there has been a significant amount of research done on short-duration, very high-intensity exercise that shows similar benefits for cardiovascular health,” Tso said. “I think what all of this really shows is that just doing something, even in small amounts, can have big benefits.”

“For sedentary people, even small amounts of vigorous exercise can improve cardiovascular health and cardiovascular risk factors,” Guse added.

“High-intensity exercise is more time-efficient in that it burns more calories, and you probably get more benefits in a shorter amount of time,” Tso continued. However, high-intensity exercise is difficult and not suitable for everyone. “So there’s a certain amount of trade-off there,” Tso said.

Before committing to a 5-minute daily workout plan, know that it may not be as beneficial as a longer workout.

“I’m not suggesting 30 minutes a week as an end goal; broader evidence supports a dose-response relationship. More regular physical activity generally has greater cardiovascular benefits, up to a point,” Guseh said.

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

Further research comparing the benefits of short periods of high-intensity exercise with those of long periods of physical activity is needed. “I’m not going to give too much weight to this one study, but it’s a good thing anyway. It just reinforced the concept that everyone should do something,” Tso said.

“I’m cautious about saying the science is settled,” Gusse said, pointing to possible limitations of the study.

“People who are able to exercise vigorously are often fitter and healthier to begin with. They have fewer symptoms and may have fewer unrecognized cardiovascular diseases and physical limitations,” Gusse added.

Regular exercise provides countless health benefits.

“Your heart and vascular system change. Your blood pressure goes down, your cholesterol goes down, and your heart size actually increases. You have more energy and can function better in your daily life,” Tso explained.

It also has a positive effect on your mood. Exercise has been shown to reduce symptoms of anxiety and depression. Exercise strengthens your bones, reduces your risk of certain cancers, is an important way to maintain muscle mass, and can even help you sleep better.

“Doctors always prescribe drugs, but exercise is probably as effective as some drugs,” Tso says.

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

“Everyone can be as active as possible or try to make time to be active,” Tso says.

Many people want to focus on getting the “best” workout at the “optimal” time, but that can become a barrier to exercise. If you only have time for a 10-minute walk today, go outside and take a walk. Much better than sitting on your butt.

“For the general public…just do something, start doing it, do it regularly, and I think this paper will probably strengthen that,” Tso said.

“Thirty minutes is a meaningful starting point, not necessarily a destination,” Guse says. “Start where you are, build up gradually, understand your risks, and make your goal a sustainable exercise habit.”