Interval training and the bodybugg

Some time ago I wrote about high intensity interval training (HIIT). One of the claims of HIIT proponents is that the intervals keep your metabolism up well after the short workout is over. Ever since I got the bodybugg, I’ve been curious to check that claim.

As it happened, my mom was in town recently, and her main exercise staple is HIIT running—one minute running, one minute walking, five times for a total of 10 minutes of exercise.  My sister Leanna and I decided to join her for a workout.  The workout itself was embarrassingly taxing; I’m supposed to be in decent shape, after all, with all the biking I’ve been doing.  You wouldn’t know it for all the gasping and coughing, though!

When we finished up, I waited a few minutes and synced my bodybugg.   I wasn’t surprised to see that it had spiked my calorie burn rate quite nicely (up from my sedentary 1-2 calories per minute to about 8 a minute for those killer 10 minutes).  But when I checked again later, I saw that my burn rate was back in my standard ho-hum range after just a couple of minutes.

Intervals are good for other things, though, and I wanted to get at least a few data samples, so Daniel and I did 30-second intervals on the road bikes one evening for 1o minutes total (in addition to the rest of the ride).  This didn’t spike my calorie burn rate as much as running (I’m guessing because I at least have the muscles for this sport) but still moved it up nicely.  No long term burn, though.

We did more road bike intervals the next night, and I ran the one-minute intervals with Leanna the day after that.  No ongoing metabolism increase followed.

So now the question is, of course, where is the misinformation?  Is the HIIT claim inaccurate, or is the bodybugg not picking up on the effect for some reason?   I honestly have no idea, and really no way of finding out.

I’m going to continue to do intervals regardless, running because I want to encourage Leanna and I figure it’s probably good cross-training in small doses, and cycling because I want to develop the ability to sprint a little more effectively.  But it seems that I’ll need to motivate myself with gains in sport-specific efficiency rather than magical weight loss!