New formula for maximum heart rate.

Experts and fitness enthusiasts have been fussing about the failure of the standard maximum heart rate formula to predict accurate heart rates for decades. The original formula, 220 minus your age, specifically tends to underestimate maximum values for older subjects. So, if you are a runner over 40, using the Maximum Heart Rate formula to calculate workout zones for quality workouts such as threshold training, for example, you are likely to set zones that may not challenge your cardiovascular system adequately to meet your training goals.

In a new meta-analysis of 351 studies that involved 18,712 subjects, funded by the National Institutes of Health, researchers at the University of Colorado confirmed that the standard formula overestimates rates for young adults and underestimates for older adults. The two formulas intersect for 40 year olds. The authors also confirmed that maximal heart rate varies with age but not gender or fitness level. They proposed a new formula, 208 minus .7(your age), which corrects the problems of the original formula. A controlled laboratory study measuring maximal heart rate in 514 adults confirmed its predictive power. This table (below) illustrates the significant differences between maximum heart rates using the two formulas. Remember that training zones are found by calculating a percentage of maximum, for example, a target zone of 70% to 85% of maximum is a general fitness, or aerobic training zone. Target heart rates of 85% to 100% of maximum are used for anaerobic threshold training.

If you use heart rates to monitor your training you may want to switch to the new, improved formula. However, you should know that all predictive formulas are limited to estimating for individuals based on aggregate data. What that means is that actual maximum heart rates, even with this better formula, can be off by as much as 10 beats per minute (the standard deviation in the Colorado study) and monitors used to measure them may vary as well.

Many experts believe that Ratings of Perceived Exertion are far better training tools and they don't require expensive, electronic gear. You probably know exactly how you feel when you put in a maximum effort, for example, when you achieved a personal best in a 5K. Ratings of Perceived Exertion are related to heart rate and oxygen uptake in a linear fashion. In other words, higher ratings indicate higher heart rates and oxygen uptake--no monitor necessary.

(Journal of the American College of Cardiology, 2001, Vol. 37, No. 1, pp. 153-156; For more information on Ratings of Perceived Exertion visit the American College of Sports Medicine Web site at www.acsm.org and click on Current Comments, Perceived Exertion, August 2001)

Age  Old Formula:      New Formula:
     220 minus age  208 minus .7 (age)

60        160              166
40        180              180
20        200              194