High Intensity Interval Training for Weight Loss

Regular aerobic exercise is a necessary component of a healthy lifestyle, and is an effective tool in weight loss regimens. People tend to begin their fitness routine enthusiastically, only to get discouraged as they grow bored with the repetitive nature of cardiovascular workouts and have difficulty fitting them into their day. Interval training is a way to squeeze more workout into less time by combining short bursts of intense activity into your regular workout. By keeping the "slow" intervals at an even higher pace, it turns into high-intensity interval training, and may help you burn more calories in less time.

Types of Interval Taining

Interval training includes three types. Regular interval training involves short bursts of increased intensity punctuated by periods of low-intensity work. High-intensity interval training uses short bursts of high-intensity work as well, but the in-between intervals are worked at a moderate rather than light intensity. In both of these methods, the work/rest intervals are timed precisely to maximize calorie burn. Fartleks, a Swedish interval training method, relies instead on the athlete's perceived exertion level to tell him when to switch modes. For example, a runner would sprint until he couldn't sprint any more, then jog at his usual pace until he catches his breath. Then he would sprint again, and the cycle would continue.


Interval training has many benefits, all of which are only enhanced by boosting the intensity. You burn more calories because your heart rate climbs higher and you use more energy to complete the intense bursts, and the switching between extreme effort and moderate effort teaches your body to use the anaerobic system more efficiently. The moderate rest intervals also teach your body to metabolize muscle wastes more efficiently, leading to fewer aches and cramps. Last but not least, high-intensity interval training helps increase the amount of oxygen you can comfortably pump in and out, allowing you to breathe harder and get more oxygen to your muscles without feeling out of breath. All of these benefits help you to perform better at any workout you do, which will only help you achieve your weight loss goals.

How It Works

High-intensity interval training works by switching the body back and forth between aerobic and anaerobic activity. During your moderate interval, you're working aerobically, using oxygen to provide energy to the body. When you dramatically increase the intensity for a short time, your body demands more energy faster than you can take in additional oxygen, so your body switches to anaerobic mode, burning stored carbohydrates for energy instead. The anaerobic mode is powerful, but it cannot last very long, so you then switch back to a moderate pace and back into aerobic mode. This gives your body a chance to recover and process the metabolic waste from your muscles before it's time for another intense interval.


The one factor that sets high-intensity interval training apart from regular interval training is the recovery period. In regular interval training, there is a greater difference between the intervals because even though the intense intervals may be very intense, the recovery intervals are very easy. For example, a runner may sprint, then walk, or even stop completely. In high-intensity interval training, you use active recovery, which means you move at a moderate pace while you recover. This means that after you sprint, you continue to run at your normal pace until it's time to sprint again. This prevents the body from recovering completely, and keeps the heart rate higher for the duration of the session, increasing calorie burn.


High-intensity interval training involves some risk. It is an intense experience that should not be done more than twice per week, with at least one day of rest in between. Begin gradually, and lengthen your intense intervals as you become more accustomed to the increased demands. Jumping right in can lead to injury, as your body will not be prepared. Wear a hear rate monitor and check your heart rate often to make sure you never go above your maximum heart rate -- 220 minus your age. If you are new to exercise or have a chronic health condition, consult your doctor before beginning high-intensity interval training.