Cardiologists and athletes usually monitor heartbeats as way to gauge fitness. But, researchers at Northwestern University Feinberg School of Medicine say, the traditional formula based on men is inaccurate for women. The result may be a number that's too high.
The traditional formula involves a math equation of 220 minus a person's age.
The newer formula is more complicated: 206 minus 88 percent of a woman's age.
If all the math is too much, don't despair. Critics say much of this heart-rate monitoring is not very useful and can distract from finding an exercise routine you like and will stick with.