Maximum Heart Rate: Women are Not the Same as Men
This article was originally written for and published in the American Academy of Health and Fitness’ Gamut of Life.
The Greek philosopher Heraclitus, as interpreted by Plato, held that the only thing constant is change. A current example of this in the health and fitness industry is how to accurately calculate a client’s maximum heart rate and subsequently a woman’s target heart rate.
For about the last 40 years, the “220 – age” calculation for maximum heart rate (MHR) has been widely accepted and used for both women and men. However, it is interesting to realize that there is debate surrounding the true origin of this formula. Dr. Karvonen, when asked in 2000 to confirm the study whereby he developed this formula, explained that he did not create it. It seems that while the physiological study of predicting maximum heart rate dates back to the 1930s, the foundation of the formula is actually an estimate, based on observation of a linear best fit of a series of raw and mean data collected 1971 by Fox et al.2 In fact, Fox wrote in the results “….no single line will adequately represent the data on the apparent decline of maximal heart rate with age. The formula maximum heart rate = 220 – age in years defines a line not far from many of the data points….” 3
Perhaps this is why the formula has been challenged – because it does not account for differences in fitness levels, exercise types and gender. Gulati et al4 recently published research that evaluated the formula’s validity. Utilizing treadmill tests, they studied 5,437 women aged 35 – 93 (mean age of 52) exercising as long and hard as they could. The researchers investigated the correlation between heart rate response to exercise testing and age. They discovered that the mean peak heart rate for women is 206 – (0.88 x age), showing that the traditional calculation (220 – age) overestimates the MHR for women. Dr. Gulati, recognizing that one calculation will not apply to all women without exception, noted that this formula is based on averages and some women may find it too low or too high for them.
It is well known that one of the measurements for cardiovascular fitness is the intensity of exercise which is indicated by target heart rate (THR). This new calculation has a significant impact on how we coach clients, as it changes the basis for determining a female client’s THR and heart rate reserve, which is the difference between a person’s resting and maximum heart rates.
For years, there have been five accepted methods to calculate THR.
- The Talk Test. This is a subjective measurement, utilizing the hyperventilation response to monitor exercise intensity. Our client should be able to carry on a comfortable conversation, somewhere between singing an entire song and gasping for breath.
- Borg’s Rating of Perceived Exertion (RPE) or the subsequently revised Category Rating Scale. These are also subjective measurements. The original RPE scale was created in the early 1980s and ranges from 6 to 20. In this case, our client is in her THR when she perceives she is exercising between twelve and fifteen. The scale was modified in 1986 by the American College of Sports Medicine for more ease of use and uses a scale of zero to ten. The client is in her THR when she perceives she is between three and five.
- Metabolic Equivalents. This is a graded exercise test measuring the maximal oxygen consumption as converted to a multiple of resting oxygen consumption. Again, a percentage of the maximum is the target.
- VO2 or Aerobic Capacity – the maximum capacity of a person to transport and use oxygen during incremental exercise.
- Heart Rate as a percentage of MHR or Heart Rate Reserve where the THR = (MHR-resting heart rate) x desired intensity + resting heart rate.
Target heart rate is defined as a range instead of an exact number so as to account for different factors. For the purpose of this article, we will use the broad range of 60 – 85% of MHR for optimum exercise intensity which includes those trying to build aerobic capacity or increase endurance.
Let’s compare the effects of this new MHR calculation for a 40-year old woman.
Old formula New formula
MHR = 220 – 40 MHR = 206 – (0.88 x 40)
= 180 = 206 – 35.2 = 170.8 ≈ 171
This is about 9 beat per minute difference! It becomes a significant disparity when cyclists, runners, and others use their MHR to determine their target heart rate.
Applying the range of 60 – 85% of MHR = THR:
Old formula New formula
THR = (180 x 0.6) to (180 x 0.85) THR = (171 x 0.6) to (171 x 0.85)
= 108 to 153 = 103 to 145
This is a 5 – 8 bpm discrepancy which may appear small in a simple calculation but if our client is exercising and aiming to reach her correct THR, it can be exhausting and potentially threaten her health if she is using the incorrect formula. Imagine exercising for 20 minutes at a 145 bpm and now think of how much harder she would have had to push to exercise for 20 minutes at 153 bpm.
This table provides a quick glance at the THR of 65 – 80% of MHR. It highlights the differences between the old formula which still applies to men and the new formula that only applies to women.
|Age||Old Formula (now for men only)||New Formula (for women only)|
|20||120 – 170||113 – 160|
|25||117 – 166||110 – 156|
|30||114 – 162||108 – 153|
|35||111 – 157||105 – 149|
|40||108 – 153||102 – 145|
|45||105 – 149||100 – 141|
|50||102 – 145||97 – 138|
|55||99 – 140||95 – 134|
|60||96 – 136||92 – 130|
|65||93 – 132||89 – 126|
|70||90 – 128||87 – 123|
|75||87 – 123||84 – 119|
This new maximum heart rate calculation for women reinforces the importance of staying current on changes that result from ongoing new research. If we choose to overlook these changes, we are providing an enormous disservice to our clients, to ourselves, and to our profession.
- Robert A. Robergs and Roberto Landwehr, “THE SURPRISING HISTORY OF THE “HRmax=220-age” EQUATION”, Journal of Exercise Physiologyonline, ISSN 1097-9751, Volume 5 Number 2 May 2002.
2,3.Fox III, S.M. Naughton, J.P. and Haskell, W.L. Physical activity and the prevention of coronary heart disease. Ann Clin Res 1971;3:404-432.
4. Gulati M, Shaw LJ, Thisted RA, Black HR, Merz CN, Arnsdorf MF., “Heart Rate Response to Exercise Stress Testing in Asymptomatic Women”, June 2010.