When I declared my exercise goal for this year, I specified a minimum of 3 times per week (which I have interpreted to mean seven-day-moving-average), but I did not specify any quantity (time) or quality (exertion?) of exercise I’d get during each of those workouts. I had already developed a routine so I had an idea of what I’d do.
With three successful months under my belt (I had a 2-week sick break in March), and Wii Fit Plus now in the house, I’ve had some time to ponder just how good my routine is.
Wii Fit Plus uses MET‘s to calculate the effectiveness (in calories) of their exercises. Most of their exercises are not very vigorous, with METs in the 2-3 range. A few are higher, but I don’t think any are over 5. Compare this to Racquetball (my former favorite exercise) which is in the 7-10 range (depending on how competitive you are … that’s a 10 for me), or flying a plane, which I’ve spent nearly 10,000 hours doing, yielding only a 2. Playing an instrument in church is a 2.5, but playing the drums comes in at a 4 (which do I use?).
My workout routine includes three major sections and averages about 26 minutes. The three major sections are stretching, cardio / whole body exercise, and strength-building calisthenics (using bodyweight). The MET compendium lists calisthenics and circuit training with vigorous effort as an 8 which covers pretty much everything I do in the cardio and strength sections. Stretching and yoga are both listed as a 2.5 which sounds right for my stretching routine.
Of my average 26 minutes, no more than 5 minutes and 15 seconds is stretching (usually a little under 5 minutes). The mathematical formula for calories burned using METs works if you proportionally allocate mets. Ergo, my workout is worth, on average ((5 x 2.5) + (21 x 8)) / 26 = 6.9. If I work extra vigorously and extend the non-stretching portions (say, a 28 minute workout), it’s probably at least a 7. If I shorten it up and don’t work as hard, it might only be a 6 or 6 1/2. I use those numbers as a ballpark for logging credits on Wii Fit Plus.
But … Wii Fit Plus only allows you to log time for METs up to 5. Consequently, I have to adjust the time to compensate for the higher MET value (again, this can be done proportionally without violating the formula). Today’s 28 minute workout valued at 6.5 METs is worth 36 minutes at 5 METs, so that’s what I logged. This gave a caloric burn of 242 if I recall correctly.
Contrast that with yesterday’s 50-minute (of actual game play) session using Wii Fit Plus’s exercises. Granted I didn’t do the most vigorous ones, but in 50 minutes I only burned 109 calories. This suggests my average MET value for that time (which took well over an hour to accumulate) was somewhere south of 2, not much different than flying (should I log that?). It’s certainly more fun than my routine, but not nearly as efficient.
Getting back to my original observation that I didn’t specify a workout intenisty, should I log Wii Fit time as a workout? I burned 109 calories yesterday, which is almost half of what I usually do (at 6.5 METs that’d be about 12 minutes). Seems like I ought to count it for something anyway. Alternately, should I count all workouts based on (estimated) calories burned rather than time?
I suppose the answers to those questions aren’t as important as the fun I had figuring all that out. Call it food for thought… or maybe exercise for thought 😉