By Andrea Wright-Agustin

“Just 20 seconds? I can handle that,” I said, arrogantly shrugging my shoulders. “We’ll see,” Dennis Tengan chuckled. “Ready … go!” I took off on the gym’s elliptical machine, pumping with furor. “OK … rest,” Dennis said, “Ten, nine … and … go! Faster!”

Not bad, I thought. Only seven more rounds. But every time Dennis yelled out, “C’mon! Push!”, my legs shook like Jell-O and the machine trembled in agony.

Dennis, my workout buddy, was introducing me to the Tabata Protocol, a demanding four-minute interval training workout that requires you to push yourself as hard as you can for 20 seconds, followed by 10 seconds of rest, then repeat the cycle eight times.

In interval training, short, intense bursts of physical activity alternate with low-intensity recovery periods. Interval training works both your anaerobic and aerobic energy-producing systems. The body’s anaerobic system provides just enough fuel for short surges of activity (usually less than two minutes) before the muscles fatigue. Anaerobic activities like weightlifting strengthen muscles and help rev your metabolism. The aerobic system helps you perform lower-intensity activities – like jogging – longer before fatigue. Your heart and lungs work hard and you build endurance.

Varying your workout between high and low intensity conditions your muscles to adapt quickly to change. This helps improve your overall fitness performance, burn more calories and fat, prevent exercise and weight-loss plateaus, and recover more easily. And best of all? You can do all this in half the time of a typical monotonous workout.

There are no rules for interval training; it can be done at any fitness level with nearly any exercise, including biking, swimming, jumping rope, abdominal exercises, and strength training. Simply increase and decrease your speed according to the time ratio you choose. The activity you’re doing and your ability will determine how you time each interval cycle and the length of the workout.

There’s no right or wrong ratio as long as you go at a pace you’re comfortable with, listen to your body, and allow enough recovery time between high-intensity intervals. Beginners might try alternating 10 seconds of fast walking with one minute of regular walking for 15 minutes, for example. An advanced trainer might alternate three minutes of speed-biking with one minute of cruising for one hour. If you don’t have a watch, you can gauge your intervals by distance. (Run one block, then walk one.) Or, simply go faster when you can, slow down when you need to, and repeat the cycle when you’re ready.

You should always warm up before interval training and don’t do it every day; your body needs time to recover. Beginners may want to start with once a week. Those with heart, lung, or joint conditions should consult their doctor before trying interval training, especially intense interval workouts like the Tabata Protocol.

Whether you’re short on time, striving for better results, or just need a change, interval training is a great way to boost your workout. Since I started doing it three times a week, I’ve had more energy, can train longer, and even dropped a few pounds. But Dennis still chuckles watching me huff, puff, and sweat through cycle number eight.