MANHATTAN — I see it all the time: people wearing fancy heart monitors on their arms or pressing their hands into the pulse reader on the stationary bike or treadmill.
It's addictive, watching the monitor flutter up and down with increasing and decreasing exertion as you think about all the calories you're burning.
There's only one problem: it's an imperfect — and sometimes misleading — way for the average gym-goer to measure the effectiveness of their workout.
It's a controversial answer that comes as a shock to the students in my interval classes, and when I used to teach spin. Cyclists and other serious athletes rely on heart rate monitors quite often, but the average gym-goer really doesn't need one
The first problem with using a heart rate to monitor your intensity is figuring out what number you should be hitting.
For more than 30 years, people have been told to use a simple formula — 220 minus your age — to determine their maximum heart rate. Therefore, an elite female athlete at 45 years old is supposed to have the same maximum heart rate as a pot-bellied 45-year-old guy, who hasn’t set foot in a gym since college. Doesn’t make much sense, does it?
There are major variations in heart rate based on gender, physical fitness, overall health and age.
There are other, more complicated formulas to determine your maximum heart rate, and you can even take an expensive test to figure it out. But if you really want to know that magic number, it probably makes most sense to just push yourself as hard as you can and look down at the heart monitor. Most likely that number will not be your maximum heart rate but approximately 90 percent of it.
The question remains, however, what do you do with that number once you figure it out.
This brings us to another huge problem with heart rate monitors — they lead some people to believe there is an optimal fat-burning zone, and, if you work out in this zone, body fat will start melting away.
Most trainers and exercise professionals have long since abandoned the fat-burning zone, but I heard just a couple months ago a trainer telling her client not to work out too hard if he wants to burn fat.
That’s crazy. In order to burn fat, you must work out and work out as hard as you can. If you lower your intensity, you burn fewer calories. If you consume more calories than you burn, you will not lose weight, and you will not become fitter.
Rather than using a fancy device, I think the best way to monitor intensity is to use Rate of Perceived Exertion — RPE. Using a scale of 1 to 10, with 10 being as hard as you can physically push yourself, try to work from 7.5 to 9.5 for the majority of your workout. Bring the intensity below a 9 if you’re pregnant.
The truth is that if you work out hard, past what is physically comfortable, your body and fitness level will change quickly. Actually, you will be able to work out less often because you are getting more out of the workouts you do.
Three to five intense workouts a week are much better than seven days on the elliptical with a magazine.
Do whatever it takes to help you to get there. So, if you love your heart rate monitor then use it, but don’t be married to any maximum heart rate formula.
If you haven’t invested in one, my advice would be to save your money and set up a session or two with a good personal trainer who can help you find your maximum intensity. It will be more than worth it.