HIIT is high intensity interval training, which means you perform a high intensity interval (+80% max heart rate) followed by a low intensity interval. The most common HIIT technique is a 30 second intense exercise followed by a 10 second lesser intense exercise like walking or sit ups. These intervals are generally repeated for about 10-30 minutes depending on the type of exercise.
A light warm up is recommended due to the increased chance of injury associated with high intensity activity. Don't forget a 5-10 minute warm down!
Benefits of HIIT VS Traditional Cardio
EPOC (Excess Post-Exercise Oxygen Consumption)
Also known as "the after-burn" in recovery. Oxygen EPOC is used in the processes that restore the body to a resting state and adapt it to the exercise just performed. EPOC includes, hormone balancing, replenishment of fuel stores, cellular repair, innervation and anabolism. EPOC burns extra calories up to 40 hours after your HIIT session - of course that depends on how hard your session was. Performing HIIT can help you burn calories all day long even if you're standing still, this will help shed fat faster.
HIIT dramatically increases growth hormones catecholamines and epinephrine. These are fat-incinerating hormone that have been shown to enhance fat mobilization release from both subcutaneous and intramuscular fat stores. To maximize hormone release, don't eat carbs 1-2 hours before you workout, the insulin response from carbs will limit the growth hormone release.
HIIT is time efficient, most workouts are from 10-30 minutes long. Way shorter than traditional cardio (40-90 minutes long) and you burn twice as much! What's not to love?
Can Be Done Anywhere
HIIT can be done in and outside the gym. Sprinting is the most popular form of HIIT, which can be done on the pavement, on a track, basically anywhere. HIIT doesn't need equipment, which is also a great money saver! So really, that gym membership isn't as beneficial.
VO2 MAX (maximal oxygen consumption, maximal oxygen uptake, peak oxygen uptake or maximal aerobic capacity) is the maximum capacity of an individual's body to transport and use oxygen during incremental exercise. This reflects the physical fitness of an individual. HIIT increases an individuals VO2 max faster than traditional cardio, and if you're an athlete, increasing your VO2 max is essential to performance.
Aerobic & Anaerobic
The high intensity portion of the workout (such as sprinting) works the anaerobic system, performing the low intensity portion (walking) works the aerobic system. By working both systems, you burn glucose and fat - the best of both worlds!
Your Body Won't Adapt
A 30 minute jog may burn 400 calories at first, but probably won't burn the same amount of calories 6 months later if you're doing it regularly. Your body adapts to things like jogging, which means it won't burn as many calories and you'll reach a plateau in your fat loss quickly.
HIIT on the other hand is unpredictable and there a lot of variables like equipment and interval length. This keeps your body from adapting, therefore you keep burning high amounts of calories and won't plateau any time soon.