Jan 222010
Susan Dawson-Cook swimming butterfly

Photo by Chris Mooney

Did you know you can turn back the biological clock by 10 years or more doing interval training? It’s true. Recent research says so. I know you want to try it right away, but hold on for a moment! First, let me explain what interval training is and how it keeps the body young.

Interval training consists of short bursts of hard work followed by short periods of active recovery. Active recovery is what it sounds like—you slow down, but keep moving. You can do interval training on the treadmill, stationary bicycle, elliptical, outside walking or bicycling, or swimming. Some group exercise formats are also interval workouts.

Here’s an example of a treadmill interval workout. You warm up for 5 minutes and then alternate between a minute of fast walking with a steep incline and a minute of slow walking without an incline, repeat that 10 times and follow that with a 5 minute cool down for a total of 30 minutes. On other days, you could change it up by adding some intervals of jogging to the high-intensity segments or changing the length of the intervals. Fit people should aim for a 1 to 1 ratio of work to recovery, with intervals ranging from 30 seconds to 4 minutes.

I recommend using a heart rate monitor to ensure heart rate stays within recommended ranges (60 to 80 percent of maximum heart rate for a healthy individual). People taking medications reducing blood pressure and heart rate should refer to the Borg Rating of Perceived Exertion (RPE) to estimate how hard they are working.

People new to interval training often need attenuated recovery periods. A healthy, fit individual can safely work at a higher intensity than a sedentary individual with health issues. Many athletes train or compete at levels higher than 90 percent of their maximum heart rate, whereas individuals with cardiac risk may be told not to exceed 50 percent of their maximum heart rate or an estimated RPE of 11 (light) on the 6 to 20 scale.*

Now on to the why…The lungs and heart work together as an oxygen delivery system, taking in oxygen and pumping and delivering it to the muscles. As we age, heart beats slower and lung capacity decreases, which means that oxygen gets delivered more slowly to muscles.  This is why we fatigue quicker and are unable to move as fast.

Training at a high intensity forces the body to make adaptations to cope with this stress by building more muscle, stronger bones, and a better oxygen delivery system in preparation for the next episode. We can delay age-related degradations in stamina and strength by doing regular interval training. In addition to keeping you younger, interval training burns beaucoup calories, not only during the workout, but for hours afterward.

*Interval training is not safe for everyone. Consult with a doctor before beginning a new exercise program.