If you exercise on a regular basis, then chances are you've looked for alternate methods to change your routine or shave some time off your workout. One of these methods is interval training, which, as the name suggests, means alternating intense and light cardiovascular activity. Variances on this technique take time off your workout by burning calories quickly while helping you build stamina and endurance [source: Mayo Clinic]. It also improves the efficiency of mitochondria -- the tiny organelles that allow your muscles to use oxygen to create energy -- which may allow you to burn fat more quickly than with a continuous workout [source: Reynolds].
Interval training can be integrated into most cardiovascular exercises but is commonly used in running, swimming and cycling. The exercises are meant to increase strength in the lungs and heart. The chance to increase stamina and endurance is appealing to athletes, but it can be a means to lose weight and get in shape for the average person as well. According to one study, people who participated in a cycling interval training regiment lost three times as much weight as those who cycled at a steady pace [source: Aubrey].
No change to a workout is worthwhile if it doesn't improve on the one you're doing now. Interval training operates differently than continuous workouts because the pause in strenuous activity helps reduce the accumulation of lactic acid, which is one cause of muscle pain. This buildup doesn't happen with interval training because the cool-down periods give your body a chance to redistribute the accumulated lactic acid. You will still experience delayed onset muscle soreness (DOMS), which is caused by muscles being stressed in ways they aren't used to, but you won't experience the immediate burning pain that you would with continuous exercise [source: WebMD].
In the next section, we'll take a look at the ways your can integrate interval training into your exercise.