High intensity interval training (HIIT) works for people who are already in shape as well as less active people. HIIT combines periods of intense exercise interspersed with periods of rest or light exercise. You can incorporate high-intensity intervals into many kinds of exercises, such as walking, jogging, swimming, cycling, Zumba classes and kettlebell lifting.
Short bursts of sprinting or other intense aerobic effort — enough to increase breathing and heart rate — alternating with periods of lower-intensity exercise or rest increase the body’s ability to burn fat. Slowing down between high-intensity intervals allows the exerciser to work harder in a given time than if the intense activity is performed without periods of rest. Evidence suggests that the fat-reducing potential of HIIT is even greater for overweight individuals with a high fat mas