By Kara Witzke • Oregon State University-Cascades

Would you know the answer if you were asked, “How long do you need to exercise to produce a health benefit?”

If you’re like most people, information overload from the fitness industry and changing guidelines have confounded a simple answer. Marathon training, Seven-Minute Abs, the 12-Minute Workout, Superslow, Orangetheory, Crossfit: Is one better than another? The way to answer this question is to look at the research, which is pretty clear. You can get healthy in a fraction of the time than we previously thought.

The skinny on the benefits of exercise

The U.S. Surgeon General states: “Engaging in regular physical activity is one of the most important things that people of all ages can do to improve their health. Even people who do not lose weight get substantial benefits from regular physical activity, including lower rates of high blood pressure, diabetes and cancer.” Despite these benefits, half of the U.S. adult population gets no moderate-to-vigorous physical activity at all and only 26 percent achieve the recommended levels. So, for most of us, modest increases in our physical activity will make a world of difference.

How much is enough?

The Department of Health and Human Services just released the newest edition of the government’s Physical Activity Guidelines for Americans for people age 3 and older. In addition to telling Americans to sit less, these new guidelines removed the recommendation that exercise should occur in at least 10-minute bouts to produce a benefit. Research is mounting that health is improved and risk of dying is reduced in those who accumulate at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity exercise every week any way they can. This recommendation has been made possible due to the overwhelming evidence that short duration (even very short duration), high-intensity exercise is remarkably beneficial to one’s health.

High-intensity is relative

High-intensity exercise, or high-intensity interval training (HIIT) as it is commonly called, refers to very short duration exercise that is done at a relative intensity that you might rate as at least a 7 or 8 on a 10-point scale. For most people, this subjective rating also equals about 70 to 80 percent of their maximum aerobic capacity. If that sounds like hard work, then you would be right. While you should be able to talk during moderate intensity exercise, HIIT makes that nearly impossible. The best part for many people, though, is that it takes much less time out of your day. Typical HIIT training sessions can be comprised of bouts that last between 10 and 60 seconds at a time for 10 to 20 minutes per session. If the exercise is this short, accumulating 75 minutes over the week is attainable for most people.

What counts as a high-intensity exercise

One of the best parts about this new approach is that almost every type of exercise that can be done at a moderate pace can also be done at a fast pace. Instead of walking on a treadmill on a 0 percent grade at a leisurely pace, you can walk briskly for 30 seconds at a 5 percent grade, followed by 30 seconds at a slower pace at 0 percent grade. Instead of riding a stationary bike at a moderate pace, do 30-second intervals as hard as you can. And the best part? You can burn the same amount of calories (and do the same amount of work) in as little as half the time. Entire gyms like Crossfit and Orangetheory base their group workouts on this exercise methodology. Does it work? Absolutely. Research shows an equal if not more profound effect of intermittent high-intensity bursts on cardiovascular health, metabolic profile, muscular development, and weight loss than with moderate (long and slower) intensity exercise. Research also shows that those who do HIIT exercise enjoy it more than those who do more traditional exercise at a steady pace.

Who should do HITT-style exercise?

Before you dismiss HITT training as too strenuous, or not for you, the research shows that it is safe and effective for all kinds of people; young and old, healthy or diseased. One caveat: If you are a male over 50 or female over 55, and have a known risk factor for heart disease, such as high blood pressure, high cholesterol, obesity and/or diabetes, you should first be cleared by your doctor before engaging in any type of high-intensity exercise. •

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