Shorter Means Longer

As a bring proponent of high-intensity interval training (HIIT or HIT), I welcome the results of a recent study by the NSCA on interval length. Interval training is high-intensity ( near maximal) cardio training followed by rest periods or low-level "active" recovery periods.

I have generally seen intervals of from 30 seconds to four minutes recommended by various sources. Personally, I employ 30 second to 2 minute intervals, depending on the equipment I'm using and how energetic I'm feeling. For clients, I have generally used 30 second to 1 minute intervals based upon their fitness level and pain tolerance. Anecdotally, clients seem to "like" (and I use this term very loosely) the 30 second intervals better and experience a lower RPE( rating of perceived exertion.)

The recent NSCA study tested 12 triathletes at 90% and 100% of maximum power output(MPO) for 30 second and 3 minute work sessions, respectively. The group that used 30 second work and rest intervals at 90% MPO were able to exercise longer than the 3 minute group. They experienced higher mean and total VO2, a higher heart rate, and a lower blood lactose concentration.

VO2 indicates the amount of oxygen consumed each minute. A higher amount means you are working harder. Blood lactate accumulation is an indication of fatigue, so the lower levels seen in the 30 second group is a good thing. So, shorter (interval lengths of 30 seconds) means longer (exercise sessions) and better ( measurable results.)

Willy Wonka: "A little nonsense now and then, is cherished by the wisest men."