Cardio Interval Training on a Treadmill

Picture of people running on treadmill in gym

Interval training is one of the best ways to boost your fitness power and lose fat. A treadmill offers the perfect tool to perform these workouts, which involve alternating short bouts of high-intensity work with equal, or slightly longer, bouts of low-intensity work.

Approach intervals at a moderate intensity, so they're aerobic, or make them all out HIIT (high-intensity interval training) sessions. Both have benefits, but HIIT is best saved for people who have an established level of fitness.

Aerobic Intervals

The goal during an aerobic interval workout is to burn calories, boost your heart rate and build stamina. You work in a heart rate zone that's aerobic — between 50 percent and 85 percent of your max — for the entire session. The bursts of higher intensity bring your heart rate into the higher end of that range, while the rest periods drop you to the lower end.

An aerobic interval workout differs from a steady-state aerobic workout in which your heart rate stays relatively stable throughout your effort. Performing this workout on the treadmill can help a person transition from walking to running consistently. It's also a solid way to build physical stamina so that, over time, you're able to perform steady-state workouts at a faster pace with less effort.

HOW TO DO IT: Warm up on a treadmill for 5 to 10 minutes at an easy pace. Then, pick up your pace for 1 to 3 minutes so that you're between 70 percent and 85 percent of your heart rate maximum. If going quickly isn't OK on your joints, ramp up the incline and keep your pace the same to raise your heart rate. Slow down — or decrease the ramp — to bring your heart rate back to 50 percent to 65 percent of your max for one to three minutes. Repeat the intervals until you've completed at least a 30-minute workout.

Senior woman running on treadmills in gym

High-Intensity Interval Training

HIIT involves alternating short bursts of hard work with rest just like aerobic intervals. The major difference is intensity. For a HIIT workout, the hard work should reach 90 to 95 percent of your heart rate max. Because the work is that much greater, the length of the intervals is likely shorter. You may also need to change the ratios of work to rest slightly, too. Instead of these being even, consider giving yourself slightly longer rest periods so you can recover enough to tackle each high-intensity interval with all-out effort.

HIIT has advantages in stimulating mechanisms in your body that encourage greater fat burning. Plus, it can be as effective as a long steady-state cardio session when it comes to building your markers of physical fitness, as demonstrated by a study published in a 2015 issue of Sports Medicine.

HOW TO DO IT: Warm up on a treadmill for 5 to 10 minutes. Gradually increase your intensity from a light walk to a moderate jog during this warm-up period. Then, raise your speed — or a combination of speed and incline — to a pace that makes your heart rate rise to about 90 percent of your heart rate maximum. If you use the talk test, conversation — or even a few words — aren't possible at this pace. Go for 30 to 90 seconds at this pace and then recover to an easy jog or walk for 1 to 2 minutes. Repeat between five and 10 times to get a complete workout.