High intensity interval training workouts use the idea of performing maximal cardiovascular effort for short periods of time. Typically when people run on a treadmill, ride a stationary bike, or workout on an elliptical they pick a time increment, usually 30-60 minutes and then exercise at one steady pace for the selected time.
In high intensity interval training, also called HIIT, individuals will exercise for only 20-30 minutes. Within that 20-30 minute HIIT training workout the routine is broken up into a 3 minute warm up followed by intervals lasting 30 seconds to 1 minute where you run, bike, or pedal the elliptical at your maximal physical effort. You then get a 1 minute recovery period before performing the next 30 second maximal effort interval of your HIIT training workout. You continue your exercise in this way allowing 3 minutes at the end for a cool down.
Why is this more effective than the traditional long duration steady pace cardiovascular program? First of all during the high intensity intervals you are using different muscle types that burn more energy than those of the muscles used during a steady pace cardio workout. With the constant change of pace your body does not get a chance to adapt to any one type of exercise and therefore burns more energy. One of the biggest benefits of HIIT training is that during your recovery period after you leave the gym your body continues to burn calories as it repairs itself. You are therefore essentially burning calories during times when you aren’t even exercising. This is what makes HIIT training workouts so effective for weight loss. You can see this training philosophy in action if you have ever watched the popular TV. show the biggest loser. You also hear about HIIT training workouts when celebrities explain how they were able to lose a huge amount of weight for a movie role.
HIIT training workouts are also effective in helping to add lean muscle mass when the workouts are combined with a diet high in quality proteins. This is evident if you have ever seen the difference between the body compositions of a sprinter vs. that of a marathon runner. Sprinters have highly defined musculature because during workouts they are using a different type of muscle fiber called fast twitch muscle fibers. The body uses this type of muscle for activities that require short duration bursts of muscle contraction. Slow twitch muscles are the opposite. The body uses these types of muscle fibers for activities that are steady paced for long durations. Use this training method and you are sure to get results.
The bottom line is that unless you are training for a long distance race or a marathon you do not need to be doing low intensity long duration cardio. If your goals are the addition of lean muscle mass, improved cardiovascular health and weight loss HIIT training workouts are the way to go.