Interval training does come with a few ground rules. Experts recommend that you don't train with interval training on consecutive days, which means you'll want to start with an every-other-day exercise plan. If you still want to work out everyday, you shouldn't work the same muscles as you do when you use interval training. For instance, if you're running, you'll want to work out your upper body instead on the days in between. You can do interval training on other muscle groups if you want, as long as you switch every other day.
Before you start, you need to stretch in the same ways you would before your normal workout. For most cardiovascular activities, this means low-impact, quick stretches that get blood circulation going. Once you're ready, it's time to enter the world of interval training.
The goal of interval training is to get your heart rate up to about 85 percent of its maximum for short bursts of time [source: Aubrey]. Depending on your experience and health, these bursts can last anywhere from a few seconds to a few minutes. This could mean switching from a hard run to an average jog, or from a brisk jog to a fast walk. You'll want to change up the duration of rest and activity every once and a while, both to keep your workout from getting dull and to keep your body from getting used to a standard.
You can apply the ideas of interval training to nearly any cardiovascular workout. This means if you prefer cycling, running, stair-climbing, swimming or even walking, you can incorporate interval training into it. It's best to start on the easy end of things. For instance, when you start, you may only want to incorporate the intense interval for 30 seconds, but as you warm up to it, you can add more and more time. Your rest periods will be based on your own body, so paying attention to your heart rate is key. Once you get back down to a moderate level, just above your normal resting rate, it's time to crank it up again.
Gyms often offer circuit interval training classes led by an instructor who changes up the exercises as well as the speed and rate of a workout. This prohibits your body from getting used to a specific movement and builds multiple muscles in one workout.
If interval training doesn't sound extreme enough for your workout, you might consider upping the ante a bit. We'll take a look at one way to do this in the next section.