One of my runners at a recent hill workout exclaimed that they were at 110% of their maximum heart rate. I acknowledged that it was a hard workout, but told her that it really is impossible to be a 110% of your maximum heart rate. “But look at my monitor”, she said, “It’s flashing 110%!” and it was. She was using one of the newer heart rate monitors that calculate a maximum for you. All you have to do is plug in your age. The monitor was not defective, but it uses pretty basic formula, probably 220 – age, to calculate the max rate. This formula works for those under 40, but tends to be skewed as you get older.  The best way to determine your max rate is to physically test your limits on the track or a hill or even on a treadmill. But if you are not so inclined to push yourself to that level, a good formula to use that accounts for age, weight and sex is: 210 minus ½ your age minus 5% of your weight. And if you are male add 4 to the result. For example, a 58 year old male weighing 160 pounds would have a maximum heart rate of 177  based on : 210 – (58*.5) – (160 * .05) + 4 = 177.  And a  45 year old female weighing 125 pounds would have a max rate of 181 based on: 210 – (45 *.5) -(125 * .05) = 181 Try it with this calculator:
M or F	Weight	Age	Calculate	Max Heart Rate
Male Female