This article comes from the current issue of the Reverse Diabetes newsletter. I thought it might be of interest to those of you who are exercising strenuously.
How Fast Should Your Heart Beat?
It seems to be part of the American DNA to push ourselves to the limit. We cram as much as possible into every hour of the day, overworking, over committing and overstressing—and the way we exercise is no exception.
It’s a too-common story: We settle into a sedentary lifestyle, until an extra ten or twenty pounds has crept onto our bellies, butts or thighs. And then we overcompensate by diving into a workout schedule that’s much too hard on our bodies. This can cause effects that range from the minor (but defeatist) “exercise burnout,” to much more serious overstressing of our hearts.
Each body is different—some people can run a mile in 10 minutes while others get winded from a walk around the block. How do you know if you’re pushing yourself enough to promote good health, but not harming your heart?
The gold standard for measuring exertion is your heart rate, or how many times your heart beats in a minute. When exercising, you want to shoot for a heart rate that’s 50 to 85 percent of your personal maximum—the point at which your heart can’t pump any harder.
Maximum heart rates tend to be fairly consistent from one person to the next, although it declines gradually as you get older. That makes it easy to calculate a target heart rate range that’s specific to your age. There are several formulas for doing this, but the simplest is merely subtracting your age from 220. For example, if you’re 40 years old, subtract 40 from 220 and you’ll get 180. That’s a rough estimate of your maximum heart rate, 180 beats per minute.
Next multiply this number by .50 and .85 to get the lower and upper limits of your exercise heart rate. In the example above, you’d get a lower target of 90 (180 x .50) and an upper target of 153 (180 x .85) beats per minute.
To know if you’re hitting your target heart rate, you’ll need to take your pulse during your workout. Locate an artery on the palm side of your wrist or on either side of your neck just under your jawbone. Press lightly with your index and middle finger to feel your pulse. Timing with your watch, count the number of beats you feel in 10 seconds. Multiply that number by 6. The number you get is the how many times your heart beats per minute. Cross-reference that with your 50–85 percent intensity scale. If you’re in your target range, every pump of your heart is beating back your diabetes and it’s potential cardiovascular complications.
If you haven’t exercised in a while, spend much of your time in the 50–60 percent range. Doctors call this the healthy heart zone, and it’s what you achieve doing a brisk walk in which you can still hold a conversation. Next is the 60–70 percent zone, which some call the fat-burning zone, and it’s where you are exerting enough to really start building muscle. Next is 70–80 percent, the aerobic zone, which you can only sustain for a limited time before huffing and puffing. Finally there is the 80–85 percent anaerobic zone, which is the range you achieve in intense but short spurts of exertion, like running sprints or lifting heavy weights.
For moderate exercisers, most of the time will be spent in the 50–70 percent range. But on occasion, push harder for maximum health!