Interval training involves alternating periods of high intensity exercise with low intensity exercise, or a recovery period. There are different ways to effectively perform this type of training while maintaining a target of burning an optimum quantity of calories during a short period of time. They are typically performed in a measure of seconds and minutes, however they can also be performed un-timed by pushing yourself during a cardio session as hard as you can handle, and then slowing down to recover. Once you feel rested, you should increase the intensity again.
When you do a cardio session at the same pace the whole time, your body goes into what is called steady state. This means that your body has adapted to the speed you are going and tries hard to conserve energy (calories). You can avoid this, shock your body and burn more calories and fat with an interval training workout mixed in with your regular cardio workouts.
With interval training you can benefit from an “after-burn" effect. This is when your fat-burning metabolism continues to burn at a higher rate hours after you are finished working out. During a conventional aerobic workout, your system returns to its base fat-burning metabolism much faster. It will revert even faster as you continue to better condition your body and your fitness level.
Doing intervals offers other advantages over steady-state cardio. They can help to strengthen your heart and lungs, increase your overall energy levels and endurance. Another major advantage is you can do them with a variety of different exercises and equipment. The following workout samples are designed specifically to be performed on the treadmill and elliptical.
Obviously each individual is in charge of the level of difficulty of the intervals and how hard they work during the work sets. The idea is to work harder than usual in your high intensity intervals and to briefly recover during the low intensity periods. Our activity level, fitness level, and endurance threshold vary so much from one person to the next, resulting in a need to appropriately modify an interval training regimen according to your body’s ability.
In the sample interval workouts, the levels increase in difficulty and intensity from beginner to advanced. However, if you need more recovery time during the workout, be sure to take it. If the intensity intervals are too extensive, go as long as you can and then try again the following week to increase the duration. The speeds / inclines given are also only examples and should be increased or decreased as needed.
Finally, too much of anything can often be more harmful than helpful. So do not forget to work in this type of training with regular strength training workouts and longer, lower intensity cardio to avoid injury and adaptation. Even an extremely fit athlete should have variety in their workout, incorporating some long and low intensity days for endurance, rest and recovery.