Maximal heart rate
from The New York Times
You might reasonably assume that the maximal heart rate formula of 220 minus age is based on a large, reliable body of data, since it is so widely employed by coaches, athletes, physicians and used as the basis of the target-heart-rate posters hanging in your local gym. But in fact, the formula has been largely discredited in recent years.
7701 Las Colinas Blvd., Ste. 800, Irving, TX 75063