Some things to remember when using a heart rate monitor and calculating your target heart rate.
Listen to your body. “If you feel sick and dizzy or nauseous, it’s irrelevant what your heart monitor says,” said Mr. Jordan. “You should slow down and get off the machine. It’s important everyone listen to their body as well as look at the heart rate monitor.”
Target heart rate is different for everyone. Don’t pay attention to my numbers or anyone else’s. Your target range could be much higher or lower.
Maximum heart rate doesn’t change over time. Your maximum heart rate is genetically predetermined and, like height and eye color, doesn’t change over time. Instead, as your fitness levels increase, your heart won’t beat faster, but it will become stronger, pumping out more blood per beat and allowing you to do more (such as pedal or run faster) at the same heart rate.
Standard formulas are unreliable. A common formula for determining maximum heart rate is 220 minus age. But this is often inaccurate. In my case, the formula says my maximum heart rate is 169, putting my target range at 118 to 152, far lower than the range of 145 to 166 that I posted on my bike test.
Not all heart monitors are equal. While the heart rate monitors built into gym equipment can serve as a guide, Mr. Jordan notes that they are less accurate than a watch with a chest strap. “Just 10 beats off is quite a difference,” Mr. Jordan says. “It can be the difference between feeling sick and working out within the appropriate level of intensity.”
Since leaving the Human Performance Institute, I have dutifully continued the 3×3 interval training, using a heart rate monitor at every workout. Weeks later, high-intensity interval training remains surprisingly fun and satisfying.
While I’m sold on high-intensity exercise, I still wish we could come up with a better name for it. How about fun, fast interval training, or F.F.I.T.?
“High-intensity interval training makes time go by faster, and it is more fun,’’ said Dr. Chriest. “It’s not jogging for an hour. I like it because the rest periods go by fast and before you know it, it’s over.”