By Michael Ormsbee, PhD, Florida State University

Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily

Research has found that doing short, intense workouts as opposed to long, low-intensity workouts not only saves you time, but also burns more fat. Professor Ormsbee dives into the specifics of how to get the most out of your workout.

Getting Started with HIIT

When it comes to High-Intensity Interval Training or HIIT, you may be wondering how to get started. Do you just go out and sprint? Chances are you won’t last very long and, if you’re like most people, you’ll probably injure yourself. 

Instead, warm-up with a few minutes of walking and exercises like jumping jacks, lunges, or body-weight squats. Then break your workout session into segments of high-intensity efforts and easy recovery.

You can find access to a number of interval or HIIT workouts online, in training books or from a coach. Some interval workouts go by minutes, some go by distance, and some just go by how you feel. However, the goal is always to work hard during the active phase and then recover for a period of time before the next active or work phase.

As you become more fit, you can extend the hard work phase and decrease the recovery time. A reasonable place to start could be 30 seconds very hard followed by one minute of easy recovery. You could even try mailbox or telephone pole intervals where you run hard from mailbox one to mailbox two, then go easy until mailbox three, and then repeat.

Is Interval Exercise Better?

You might even find interval exercise to be more enjoyable, as it breaks your workout down into segments and makes the time go by more quickly. Actually, it does go by more quickly because you can work out for less total time.

Research shows that interval training results in a greater overall adherence to exercise, and may be more enjoyable than continuous lower-intensity exercise. This is just one of many reasons for its effectiveness. 

“In fact, in my own research, we’ve shown that interval training combined with resistance training is incredibly effective for reducing body fat levels,” Professor Ormsbee said.

HIIT is thought to have this effect in part because it has been shown to increase mitochondrial density and to increase the number and activity of enzymes like citrate synthase, malate dehydrogenase, and others needed to break down carbohydrates and fat to make ATP. 

In some HIIT research, changes in these enzymes were shown after just seven weeks of exercising three days per week by doing four to 10, 30-second maximal sprints on a bike, followed by four minutes of recovery. HIIT has also been shown to be as effective or maybe even more effective at improving heart health than low-intensity exercise that burned the same number of calories.

When it comes to exercise intensity for fat loss, then, choose higher over lower. The best way to do this may be through interval training. 

Considerations for HIIT

Keep in mind, though, that this level of activity is very hard, so you really shouldn’t do it every day. It is best to mix in days of HIIT and days of slow-to-moderate intensity aerobic exercise. This should help to maximize fat loss and keep you from getting hurt.

Start with an amount of time that you can fit into your schedule. 

“We have shown great results with HIIT for just 20–30 minutes,” Professor Ormsbee said. “Essentially, you can start with very little exercise and have a great response for improving your body composition.”

In tomorrow’s article, we’ll cover frequency—how often you should be exercising to obtain your ideal body composition.

Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his MS in Exercise Physiology from South Dakota State University and his PhD in Bioenergetics from East Carolina University.

This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.