Understanding Interval Training

Targeting Maximum Fat Loss Through High-Intensity Interval Training

High-intensity interval training (HIIT) is a form of exercise that is growing in popularity. HIIT combines two of the most effective fat-burning methods.

The first method is high-intensity training, which pushes the body to maximum effort to achieve muscle fatigue and maximum oxygen use in a quick burst. Think sprinting or heavy weight lifting. The harder muscles work, the more oxygen they require. This is measured relative to one’s maximum amount of oxygen their body consumes during exercise. Working your body close to its oxygen max triggers the Afterburn Effect, where the body continues to consume oxygen (and burn calories) up to 48 hours after the workout (it takes approximately five calories to consume one liter of oxygen).

The second method is interval training, which alternates periods of intense effort with periods of moderate-to-low intensity effort. Interval training boosts metabolism significantly longer than a steady workout of equal or even greater length (for example, a 20 minute workout of alternating high/low-intensity periods burns more calories than a 20 minute workout of steady intensity). Interval training also builds lean muscle tissue faster than steady state training.

So instead of jogging for 30 minutes you alternate between sprinting and brisk walking for 30 minutes. Due to the Afterburn Effect it burns even more calories than plain jogging, even though the distance traveled and the time is the same.

By combining the above two exercise methods, exercisers can maximize fat-burning and muscle-building potential through significantly shorter workouts. HIIT also maximizes increased metabolic rate, optimizes muscle building and muscle retention during fat loss, and increases calorie burn during and after workouts.

The Science Behind Interval Training

HIIT taxes and maximizes both aerobic and anaerobic fitness, while light cardio addresses aerobic only. Aerobic respiration requires oxygen to generate energy in the form of ATP, while anaerobic respiration does not. HIIT affects muscle tissue at the cellular level, actually changing mitochondrial activity in the muscles themselves.

University studies indicate as little as 27 minutes of HIIT three times per week produces the same anaerobic and aerobic improvement as 60 minutes of steady state cardio five times per week.