High-intensity interval training, or HIIT, is a form of cardio exercise that combines short bursts of speed with longer periods of active recovery. The high-speed intervals allow you to cover distance faster and work your cardiovascular system harder, and the slower intervals allow you to catch your breath and recover. Overall, HIIT can give you the same benefits as steady-paced cardio in less time.
HIIT
According to exercise physiologist Pete McCall, you should do the high-intensity sections of HIIT training at about 80 percent of your maximum heart rate. If you don't wear a heart monitor while you exercise, aim to feel like you are working at level seven on a scale of one to 10. Your intense intervals should be 30 seconds to two minutes long, and for each minute at high intensity, you should give yourself two to three minutes at low intensity to recover. This kind of exercise is more tiring than long, steady workouts.
Benefits
When you work at a high intensity, your body switches from aerobic metabolism to anaerobic metabolism, meaning your cells stop drawing energy from oxygen and begin using other fuel sources. While this form of exercise is more fatiguing than the aerobic exercise you do in a long workout, it also strengthens your heart and trains your muscles more efficiently. Less intense workouts build the same systems, but they require more hours of exercise each week to achieve the same results.
Calories
Long, moderate-intensity workouts put your heart rate in the "fat burning" zone, a metabolic system that uses more energy from calories stored in your body as fat than from carbohydrates. HIIT works your heart harder and forces your body to use carbohydrates as fuel instead, so a lower percentage of the calories you burn come from stored fat. However, HIIT burns far more calories in total, so despite the lower percentage, you still burn more calories from fat. According to Michael Bracko of the American College of Sports Medicine, HIIT also increases your metabolism for up to 24 hours.
Considerations
HIIT places higher demands on the body than long workouts do. If you are out of shape or you have a medical condition that intense exercise can aggravate, HIIT might not be safe for you. Talk to your doctor about whether you should try HIIT or exercise less intensely. McCall says to do HIIT sessions a maximum of twice per week, on non-consecutive days, to allow your body time to recover. To train safely at high intensities, warm up for five to 10 minutes at a low to moderate level before you do any harder intervals.
References
- American College of Sports Medicine: For All-Day Metabolism Boost, Try Interval Training
- American Council on Exercise: What Is High Intensity Interval Training (HIIT) and What Are the Benefits?
- MyFoodDiary.com: Aerobic vs. Anaerobic: What Is the Difference?
- American Council on Exercise: Will I Lose Body Fat More Efficiently by Performing My Aerobic Workouts at a Low, Rather Than a High, Intensity?
Member Comments