Interval-Based Exercise Training

Interval training is a unique and powerful way to train that is time-efficient and burns more total calories than regular training. It involves the performance of higher intensity exercise followed by recovery periods in a very specific time frame. The purpose of performing short bouts of high-intensity exercise is to reach overload, or uncomfortable intensity levels, throughout your training routines. 

Obviously, it would be impossible to exercise at such high-intensity levels for an entire 30-minute workout. This is why there are built-in rest periods—not enough to allow you to fully recover, but enough to challenge you appropriately during these quick-paced,time-efficient workouts. The interval training formulas outlined here are based on the body’s energy systems(anaerobic and aerobic) to offer you a scientific approach to interval training.

The best ratios are those that are related to the ATP-PC, anaerobic glycolysis, and aerobic energy systems. Because these systems become depleted in very specific time frames, we use ratio intervals to follow their energy depletion and consequent recovery. The work in the work-to-rest ratio is anaerobic; that is, you work until you become breathless or close to it (this uses the ATP-PC, or anaerobic glycolysis, system), and then recover aerobically so you can catch your breath enough to prepare you for the next interval.

Most important with interval training is to remain consistent. If you decide to run on the treadmill at a 2:1 work-to-rest ratio, you need to stay true to the intervals and not decide halfway through that you need more time to rest or can wait another minute. The training benefit comes from the overload that results from the consistency of the ratios. For example, if you decide that the hard part will take two minutes and your recovery will take one minute, stick with that routine during the entire workout to the best of your ability.

You have the flexibility to select any work-to-rest interval range you would like within any of the three heart rate zones. Use the following ratios to determine which works best for you depending on how long you need to work hard and how long you need to recover. Also included are some examples of activities using the ratios. If you understand the work-to-rest ratio design, however, you can devise your own ratios and choose any activity you like (e.g., cycling, outdoor walking, or jogging).

1:1 Work-to-Rest Ratio 

A 1:1 work-to-rest ratio means that you work and recover for the same amount of time. Following are sample 1:1 work-to-rest ratio activities:

• Treadmill: Alternate five minutes of running (at 5 mph, or 8 km/h, or faster)with five minutes of walking (at 3.5 to 4 mph, or 5.6 to 6.4 km/h) for a total of 30 to 45 minutes.

• Elliptical trainer: Alternate two minutes at a high intensity (as hard as you can work while still maintaining good form, posture, and control) with two minutes at a moderate intensity for a total of 30 to 45 minutes.

2:1 Work-to-Rest Ratio

A 2:1 work-to-rest ratio means that you work for twice as long as you recover. 

Following are sample 2:1 work-to-rest ratio activities:

• Treadmill: Alternate three minutes of running (5 to 7 mph, or 8 to 11.3 km/h)with 90 seconds of jogging (5 to 5.5 mph, or 8 to 8.9 km/h) for a total of 30 to 45 minutes.

• Elliptical trainer: Alternate 40 seconds at a high intensity (as hard as you can work while still maintaining good form, posture, and control) with 20 seconds at a moderate intensity for a total of 25 to 30 minutes.

3:1 Work-to-Rest Ratio

A 3:1 work-to-rest ratio means that you work three times as long as the recovery. Following are sample 3:1 work-to-rest ratio activities:

 Treadmill: Alternate 15 minutes of running (5 to 6 mph, or 8 to 9.7 km/h) with five minutes of jogging (6 to 7 mph, or 9.7 to 11.3 km/h) for 30 to 45 minutes.

• Elliptical trainer: Alternate nine minutes at a high intensity (as hard as you can work while still maintaining good form, posture, and control) with three minutes at a moderate intensity for 30 to 45 minutes.

Remember, too, that you can change the work-to-rest ratio into a rest-to-work ratio if you need to. For example, if working hard for two minutes with only one minute of recovery (2:1) is too much for you, simply flip it and use the ratio as a rest-to-work ratio instead—working for one minute and then recovering for two minutes (1:2).