This is the second part in a multi-part series of what kinds of “essential” fitness gadgets are out there, whether you could possibly live your life without them, and whether they’re worth it anyway.
Heart rate monitors. The first time I saw one outside of a doctor’s office was during a PE class in college. Your basic fitness heart rate monitor consists of a chest strap with sensors that read the electrical activity of your heart through sweaty contact with your skin. If you’re not sweaty, in order to get a reading, you’ll want to dampen the chest strap under the faucet first. Heart rate monitors provide instant feedback on how many beats per minute your ticker is ticking. More expensive models will take that data plus personal data you input (age, sex, resting heart rate, V02 max) to tell you how hard to work out and how many calories you’re burning at any given moment. Some will transmit that data to the cardio machine you’re working out on so you can read it on the machine monitor instead of your monitor’s wrist watch.
Are you asleep yet? That’s probably the most boring biofeedback ever. If a GPS device and a heart rate monitor walked into a bar, the GPS device would totally score some phone numbers. “Hey ladies,” GPS says, “I just ran a 3,000 foot mountain. 5 miles. 30 minutes. Uphill both freaking ways!” Meanwhile, Heart Rate Monitor is alone in a corner drinking a beer and thinking about trying the pinball machine. “195 beats per minute? Anyone? Bueller…?”
Ok, well, aside from the questionable sexiness of the data you get from a heart rate monitor, let’s look at how you’d get said data without a sweaty chest strap tucked under your boobs (or nips, if you’re a guy).
Heart Rate Monitors
The old-fashioned way: If you don’t have a heart rate monitor, all you need is a watch or a clock. Take your pulse either on your wrist or the carotid artery in your neck using your first two or three fingers (not your thumb, because your thumb has a pulse too). I personally find the carotid artery easiest. How accurate you want to be depends on how much math you want to do in your head. You’ll get a good ballpark reading by counting the number of heartbeats in 10 seconds and multiplying by 6 for your total beats per minute. I’m lazy enough that I usually take my pulse for 6 seconds and multiply it by 10.
If you don’t give a damn about your pulse and just want to know how hard you’re exercising, you could follow Borg’s Scale of Perceived Exertion. Your Rate of Perceived Exertion (RPE) is basically a fancy way of asking yourself, on a scale of 1 to 10*, how close am I to feeling like I’m going to bust a lung?
*On a side note, Borg’s original scale went from 6 to 20. I guess anything less than that assumes you’re dead or in a coma?
But is it worth it? It really depends on what you want from it. I’ll tell you why I originally got a Polar F11 heart rate monitor, and why it’s been buried in the bottom of my gym bag for the last two years. Before I read Born to Run, my standard method for avoiding knee pain due to flat feet was a combination of incredibly expensive prescription insoles and supplementing running with a similar, low-impact activity: the elliptical machine. If you’re counting calories, you find out pretty quick that gym equipment — elliptical and treadmill alike — grossly overestimates your calories burned. In my Human Machine days, numbers were my life. I had to know what my basal metabolic rate (BMR) and total daily energy expenditure (TDEE) were, plus how many extra calories I was burning on top of that so that I could compare calories in to calories out and conquer the ambiguous flesh bag that was my body. Sounds healthy, doesn’t it?
What I didn’t know, of course, was that, while more accurate than the cardio machine, heart rate monitors aren’t that accurate either. At least not if you’re female.* Even Polar’s OwnCal method of personalizing your heart rate monitor overestimated calories burned by 12% in women. Guys, you’re fine, the margin of error was only like 2%.
*The few exercise-related studies that focus on men and women as separate groups show that we do have significant physiological differences. This suggests that ladies should take the male-dominated body of exercise knowledge of the last 50 years with a grain of salt.
The discrepancy is due to the method of calculating calories. It relies on your V02 max (how efficiently your body uses oxygen during exercise), which most heart rate monitors estimate based on average data for people of your age and gender. More expensive heart rate monitors let you input a custom V02 max, which you can get by having a doctor strap a mask to your face and shove you on a treadmill.
So yeah, don’t get a heart rate monitor if you just want to figure out how many calories you’re burning.
However, that doesn’t mean they can’t be a great training tool for beginning exercisers. Even though all I wanted were the calories, what I really learned from using one was that I was way too hard on myself. I would practically elliptical my legs off, then be mad at myself if I couldn’t finish a whole, say, 45 minutes at that pace, because I was missing out on all sorts of calories burned.
The heart rate monitor clearly indicated that I was trying to do entire workout sessions at my heart rate threshold, not at my target heart rate. You shouldn’t work out at your threshold for more than a few minutes at a time. This is called High Intensity Interval Training (HIIT), and is incredibly effective. However, removing the “interval” part is just plain stupid. When you’re exercising within your target heart rate (and estimations are totally fine here), you’re increasing your aerobic capacity. Stronger heart, more stamina, more energy, and can we say hello, endorphins? Also, from a psychological standpoint, you’re much more likely to enjoy and desire to continue exercise if you don’t feel like a total failure every time you go to the gym.
Now, I only use my heart rate monitor when I’m curious about the intensity of a new exercise. My heart rate monitor lead to the discovery that my exertion playing Dance Dance Revolution on Difficult is comparable to jogging for the same amount of time. Sweet!
If you’re an experienced exerciser, I’d say you could pass on the heart rate monitor. They’re pretty good learning tools, however, and I’m sure they have their place for elite athletes with a coach and doctor to guide their use.