There’s No Such Thing as a Free Calorie

I have a very generous watch. No, it didn’t buy me Christian Louboutin boots for Christmas but it gives me something I treasure almost as much. Aw heck, I’ll be honest – probably more: a high calorie burn.

Let’s get one thing straight: when I work out, I work out hard. I’ve been known to sweat so much there isn’t a single dry spot on my tank top. I breathe hard, my heart pounds, my muscles quake, sometimes I even see stars. And I love it. I live for that endorphin rush. But I don’t work nearly as hard as my watch gives me credit for.

About 6 months ago I bought a lovely little Timex triathlon heart rate monitor that has become my #1 workout companion. Up until then I had worked out lo this many years completely unwired but my gym buddies convinced me to get one with their constant chatter of heart rate zones, max and mins and – laaaa! – calorie burn. I mean, I felt like I was working harder than the gal next to me but was I really?

According to my watch, I’m kicking everyone’s butts. So much so that it’s become a bit of a joke. My two workout buddies both have Polar monitors, judged to be the gold standard, and even taking into account our ages, weights, heights, and genders, my watch still grossly overestimates. But at least I know that it does.

Your Treadmill is Lying to You
According to my favorite Gina Kolata of the New York Times, every heart rate monitor – whether it be of the chest-strap variety or the grab-your-machine-in-your-sweaty-palms variety – is wrong. Wildly wrong.

The first problem is that every person is different and machines calculate that lovely little calorie number based on calculations of what the manufacturer deems average (and every manufacturer defines that differently). Are you average? I pride myself on being, well, a freak. Kolata reports, “Claude Bouchard, an obesity and exercise researcher who directs the Pennington Biomedical Research Center in Baton Rouge, La., found that if, for example, the average number of calories burned with an exercise is 100, individuals will burn anywhere from 70 to 130 calories.” And when I look at my workout buddies, I know darn well who is torching 130 calories (*cough* 12% body fat *cough*) and it isn’t me. Yet my watch routinely gives me more calories burned than hers gives her. We even traded monitors for a workout (you should have seen people’s faces when we went into the bathroom together – “look ma, they’re so close they even pee together!”) to see what happened and, sure enough, my calories dropped by about 200. I immediately traded back. See why I loooove my watch?

The second problem is that every machine is different. “They drift in speed and grade,” Dr. William Haskell, an exercise physiologist at Stanford explains. “If you go from one machine to another, it is obvious that at the same setting you are working much harder on one and much less on the next.” I have seen this first hand on the stair climbers at my gym. Last time I was suckered on to one of those climbing monstrosities I had it down all the way to level 1 and still couldn’t move my feet fast enough to stay off the floor. It also had an adverse affect on the workouts of those around me as they were all laughing so hard they fell off their respective machines. I’ve told you all before – sometimes it is dangerous to work out with me.

So Why Bother?
If I know that my watch is off and I know that the counts on the machines are off, then why bother with the counting at all? It can be a bad thing if you use your “calories burned” to judge how many calories you can eat during the day. Since no machine errs on the side of too few calories burned (no one would buy that treadmill!), it is guaranteed that your calorie burn is being overestimated. Which would lead you to overestimate your calories allotted for the day. Which would lead you to become horribly obese, get diabetes, have all your limbs amputated and DIE ALONE IN A PUDDLE OF CHEETOS AND BE BURIED IN A PIANO BOX. Ahem. (Sorry, even I get caught up in the media hyperbole sometimes.)

For me, it’s just another tool. I don’t take the actual number seriously but I do look at my heart rate – I’m assuming at least that is accurate as it is strapped to my actual sweaty chest – to gauge how hard I’m pushing myself. I also use the calorie count to judge how I am performing compared to similar workouts on other days or even entirely different workouts.

The End of the Story
I’m going to keep my happy little watch. It’s a psychological thing. It makes me smile to see it crowing 1300 calories for one workout. It motivates me to keep pushing it a little harder. It’s a good tool for comparison purposes. But I’ll always take those numbers with a grain of salt and I hope you do too.

Anyone else have an excessively enthusiastic heart rate monitor?!?