There’s a little secret in the fitness world called interval training. Rather than doing the same cardio exercise for an entire workout, interval training alternates short, high-intensity bursts of exercise with slower, low-intensity periods of recovery.Research has shown that such intervals of high and low-intensity activity burn more calories and build fitness quicker in a shorter amount of time.Once designed for elite athletes, interval training is now something the average fit person can try. You don’t need fancy equipment or special training to rev up an exercise routine with interval training.Theory behind interval trainingBy alternating high-intensity movements with low-intensity movements, you’re working both the aerobic (with oxygen) and anaerobic (without oxygen) systems. High-intensity exercise causes muscles to produce lactic acid (waste products), which leads to muscle soreness. Too much lactic acid buildup causes exercise to become exhausting and painful.Alternating hard and easy exercise will reduce the amount of lactic acid that accumulates; thereby, making exercise more comfortable, improving endurance and increasing speed.Interval lengthThere are no hard and fast rules about interval length. Varying lengths bring varying benefits.Beginners should aim for no longer than 30 seconds of high-intensity bursts. If you’re feeling strong and are in good shape, go a bit longer.Know the risksRushing into high-intensity exercise may lead to injury. Start out slowly. Add one or two high-intensity intervals each workout. Slow down if you feel you’re overdoing it. As stamina increases, challenge yourself.Sample workoutsRemember, there’s no set rule about how to do interval training. It can be tailored to fitness levels and types of exercise.An interval-training workout involves four variables that can be changed to meet goals: intensity of intervals, duration of intervals, duration of recovery intervals and the number of interval repetitions.Interval training can be casual, spur of the moment bursts of activity, depending on how the body feels. If you’re working toward a more specific sports or fitness goal you can take a more sophisticated, scientific approach.Interval training workouts have been designed for sprints, stair running, jump rope, speed drills and agility drills.A simple example of interval training for walking would be to add short bursts of jogging or alternate slower walking with brisk walking. If you walk outdoors, jog or walk faster between certain landmarks, such as mailboxes or street signs, then slow down for a short distance.A second example that gets the heart pumping and improves fitness in a short amount of time includes running, rowing or cycling. Warm up for about 15 minutes, then run, row, or cycle as hard as you can (at 90 percent of your maximum heart rate) for three minutes. Then, go easy for three minutes, allowing your body to recover. Repeat these three-minute intervals of high- and low-intensity exercise three or four times. Then cool down for 10 minutes.Increase intensityTo get the most out of interval training, try the following:
- Add resistance: Between sets of cardio do a set with dumbbells, resistance bands or with your body weight.
- Increase speed: Push yourself during the sprinting intervals. Remember, it’s only a handful of seconds.
- Lengthen interval: Add a few seconds to intense intervals.
- Change exercises: If you’ve been sprinting then switch to burpees or high knees.
