Washington: Researchers have said that the formula for peak exercise heart rate that doctors have used for decades to diagnose heart conditions may be flawed as it does not account for differences between men and women.
The simple formula of "220 minus age" has been widely used to calculate the maximum number of heart beats per minute a person can achieve.
Many people use it to derive their target heart rate during a workout. Doctors use it to determine how hard a patient should exercise during a common diagnostic test known as the exercise stress test.
After analyzing more than 25,000 stress tests, the researchers found significant differences between men and women and developed an updated formula to reflect those nuances.
Thomas Allison, M.D., cardiologist and director of stress testing at Mayo Clinic, and senior author of the study, said that the standard that's currently in use is somewhat outdated.
The new formula can help people better optimize their workouts and also improve the accuracy of test results. Stress tests, which are commonly used to help diagnose conditions such as coronary heart disease, heart valve disease and heart failure, require patients to exercise near their top capacity while technicians monitor the patient's cardiac performance.
The researchers drew data from 25,000 patients who took stress tests at Mayo Clinic between 1993 and 2006. The sample included men and women 40 to 89 years of age who had no history of cardiovascular disease.
Women in the age range of 40 to 89 years should expect their maximum heart rate to be 200 minus 67 percent of their age. In men, the formula is 216 minus 93 percent of their age. For women younger than 40, the relationship of heart rate to age may be different, as an insufficient number of tests on women younger than 40 were available to provide reliable results.