The Basics of High-Intensity Interval Training

High-intensity interval training (HIIT) has emerged in the last decade as a style of cardiovascular exercise that is especially helpful for burning fat, building strength, enhancing endurance, and improving glucose metabolism (the way your body burns energy). HIIT has become an essential tool in most personal trainers’ and athletic coaches’ toolboxes.

“HIIT is one of the easiest and most efficient ways to burn more fat and lose weight without losing muscle,” says Brek Montoya, BS, ACSM-CPT, a personal trainer and fitness instructor at Canyon Ranch and The University of Arizona, “It's quick, challenging, and incredibly effective!”

As the name implies, HIIT mixes short bursts of high-intensity movement with low- to medium-intensity recovery periods. For example, after a short warm-up period, you would give a maximum 100-percent effort into a full-out run on the treadmill for 30 seconds, then slow to a brisk walk or jog at about 60-percent effort for 1 minute, and repeat that cycle for 20 minutes.

Or you might do jumping jacks as fast as you can for 20 seconds, rest for 10 seconds, and then run in place as fast as you can for 20 seconds and rest for 10 seconds, and repeat that five times.

While you might first think of HIIT in regard to running, you can actually do a wide variety of exercises in alternating levels of intensity, too, such as rowing, swimming or jumping rope. You can even do HIIT with body weight exercises like squats, push-ups, or tricep dips.

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Advantages of HIIT training

If you want to see results fast, try HIIT, which offers a number of advantages over some other forms of exercise. For example:

• Fat-burning: Research has shown that most of the fat that leaves your body exits through your nose as part of the breathing process. HIIT training is designed to make your lungs work more efficiently by enhancing your maximum oxygen uptake. The more oxygen you take in, the more fat you expel along with all that carbon dioxide.

• Convenience: HIIT can produce the same results in less time. One study demonstrated that 2.5 hours of HIIT training produced about the same success as 10.5 hours of endurance training. Whether or not that’s true for everyone, the fact is that HIIT workouts are usually shorter, so you spend less time at the gym. In fact, you don’t even need a gym. You can do HIIT in your living room. All that equipment is totally optional.

• Weight loss efforts: The seemingly magical benefit of HIIT training is the fact that fat continues to burn faster for 24–48 hours after your work out! So if you put in the extra effort to do HIIT, you’ll still be burning extra calories while you crash on the sofa later.

  Crashing is perfectly fine. Just don’t crash with a bunch of snacks that will annihilate the benefits of your workout.

• Insulin resistance: Regular workouts that integrate HIIT training help to increase insulin sensitivity, which can help protect you from diabetes.

• Strength: While steady-state cardio (such as running at the same pace for the duration of your run) is an aerobic exercise good for weight loss and general conditioning, HIIT employs anaerobic exercise. This means it goes beyond aerobic exercise by also promoting muscle growth.

Don’t make the mistake and think you only need HIIT. The best results for all-around fitness come from a combination of HIIT workouts with steady-state cardio and some free weights. Remember, the more you vary routine — so long as you’re always giving it your all — the better your overall fitness.

Consult a physician before beginning any new exercise program.

It’s a good idea to do a brief warm-up prior to any workout to reduce the chance of injury. A brisk, five-minute walk around the block or on the treadmill will do the trick.

Sample HIIT workouts for beginners

The possibilities are limitless where HIIT is concerned. Following are a couple of different HIIT workouts for beginners to try.

Form is important! A wide variety of books and videos are available to show you the proper way to perform for each exercise without injury and for maximum effectiveness. One good resource is the video database at Bodybuilding.com.

You can buy an interval timer that beeps at you when your intervals start and stop. You can also download a number of smartphone apps that do the same thing.

Be sure to allow time to adjust your machine if you’re using one. Don’t fudge on the start and end of the high-intensity interval, push through the entire time. (It will be over before you know it!) If anything, take a second or two less of rest. You might detest the thought in the moment, but you’ll be glad you did when the results start showing up.

HIIT workout #1 (low-impact)

Perform each move as hard and fast as you can for 20 seconds, and then rest as directed.

This workout is gentle on your joints, but don’t let it fool you — you’ll feel the burn before long.

• Squats 20 seconds

• Rest 10 seconds (usually about as long as it takes to get into position for the next move)

• Push-ups 20 seconds

• Rest 10 seconds

• Lunges 20 seconds

• Rest 10 seconds

• Plank 30 seconds

• Rest 1 minute

Then start over. Repeat the entire circuit three times, for a total of 9 minutes.

HIIT workout #2 (high-impact)

This one is a little harder. Perform each move as hard and fast as you can for 30 seconds, then rest as directed.

Don’t do this workout if you have knee, back, or joint problems.

• Jumping jacks 30 seconds

• Rest 1 minute

• Burpees 30 seconds

• Rest 1 minute

• Mountain climbers 30 seconds

• Rest 1 minute

• High knee march 30 seconds

• Rest 2 minutes

Then start over repeat the entire circuit, for a total of 14 minutes.

If these HIIT workouts are too difficult at the start, decrease the intense interval or increase the rest interval to something that works for you. Over time, you’ll be able to push your limits longer and need less rest in between.