Maximum heart rate (or pulse rate) [HRmax] is the fastest / quickest rate at which your heart can beat. In the normal situation maximum heart rate is achieved in response to exercise. It is influenced by various factors, including age, genetics, and overall fitness level.
Traditionally, the widely used formula for estimating maximum heart rate is “220 minus age,” which suggests that maximum heart rate declines with increasing age. However, this formula has limitations and may not be accurate for everyone. It provides a rough estimate, but individual variations can be significant. The only accurate way to make an assessment is via an exercise (cardiac) stress test to measure directly. These, particularly for people at the start of their fitness journey, should only be undertaken under medical supervision due to their inherent risks associated with inducing high heart rates.
During intense exercise or activities like running, the body demands more oxygen to fuel the muscles. To meet this increased oxygen demand, the heart must pump blood around the body at a faster rate. The maximum heart rate is reached when the heart is operating at its maximum capacity, and further increases in effort do not result in an elevated heart rate.
It has been observed that individuals of the same age, and similar training in the same sport, can have measured HRmax values 60 bpm apart, which strongly calls into question the application of estimation formulae.
It’s important to note that maximum heart rate provides a reference point. And additionally, factors such as fitness level, medication, hydration status, and overall health can influence an individual’s response during exercise.
Knowing your maximum heart rate might be useful for determining appropriate training zones and intensities. Heart rate training zones are typically calculated as a percentage of maximum heart rate. For example, moderate aerobic exercise might target 50-70% of maximum heart rate, while high-intensity interval training could aim for 80-90% of maximum heart rate.
Common Estimation Formulae
There are over 30 formulae to estimate maximum heart rate, all sharing the same feature of being dependent on age alone. The two most common ones are presented below.
220 – age
Certainly the most well known formula, and presented in countless textbooks, articles and used by a plethora of computer applications. However, despite the widespread use and acceptance of this formula there is no published record of research for this equation and review advises that it has no scientific merit for use in exercise physiology and related fields. It is estimated that it has an error standard deviation of ~12 beats, suggesting 95% of people will have a true value less than or greater than calculated by 24 beats per minute (a range of 48 beats!).
Whilst attributed to Fox and Haskell, the origins of the formula are vague, though it is understood that they did not derive the formula from original research. Additionally, if one derives a regression formula from the Fox et al manuscript data a different result is achieved: HRmax = 215.4 – age * 0.9147. So even the original data from which the observation established the formula does not support the equation.
208 – (0.7 * age)
Utilising both meta-analysis and laboratory studies, Tanaka, Monahan, & Seals published this formula in 2001. They concluded that HRmax is to a large extent predictable by age alone and is independent of gender and habitual physical activity status. Their study demonstrated a standard deviation of ~10 beats per minute, suggesting a 95% accuracy of ±20 beats per minute. It is probably considered one of the more accurate formula, but with a range of 40 beats, still does not seem great for training purposes.
References & Further Reading
- Resting Heart Rate.
- Robergs, Robert A. & Landwehr, Roberto (2002). The surprising history of the “HRmax=220-age” equation. Journal of Exercise Physiology Online, 5(2), pp. 1-10.
- Hirofumi Tanaka, Kevin D Monahan, Douglas R Seals (2001). Age-predicted maximal heart rate revisited, Journal of the American College of Cardiology, Volume 37, Issue 1, pp 153-156.
- Kolata, Gina (2001). “‘Maximum’ Heart Rate Theory Is Challenged”, New York Times.
- Gellish, R.L. et al. (2007) Longitudinal Modeling of the Relationship between Age and Maximal Heart Rate. Medicine & Science in Sports & Exercise, 39 (5), p. 822-829.