PRINTED ON TREADMILLS and exercise bikes in gyms around the world is a simple method for estimating the maximum rate at which your heart should safely beat, in beats per minute: 220 minus your age. This neat formula is endorsed by august bodies like the American Heart Association and the British Heart Foundation. By this calculation a 50-year-old should expect their upper limit to be 170 beats per minute. But studies have shown that people of the same age can have wildly varying maximum heart rates. No simple formula will cut it.
Knowing your maximum heart rate can be useful when planning exercise. Workouts in lower “zones”, defined as up to 70% of maximum heart rate, improve aerobic capacity. More intense exercise trains anaerobic fitness.
Unlike resting heart rate, which can be lowered with training, there is little one can do to change the maximum. As exercise gets more intense, heart rate rises to deliver more oxygenated blood to working muscles. But there is an upper limit. Once the interval between beats becomes so brief the heart’s ventricles cannot fully refill before the next contraction, less blood is pumped with each pulse. Cells in the heart’s natural pacemaker, the sinoatrial node, determine the ceiling. They can only fire electrical impulses so fast, limiting the number of beats per minute.
Most people do not know their true maximum. Assessments to determine it in athletes push them to their limit and are typically only done under medical supervision. Everyone else uses a formula based on their age. Studies have shown that ageing reduces the level of electrical activity in the heart’s pacemaker, which lowers the maximum heart rate that can be achieved.
The “220 minus age” formula was the first attempt to put a figure on how age affects maximum heart rate and traces back to a paper from 1971. By modern standards, though, the evidence for the formula is flimsy, explains Robert Robergs, a professor of exercise physiology and biochemistry at Jan Evangelista Purkyne University in the Czech Republic. The original study combined data from several sources without stringent criteria about the subjects or exercise protocols, and the formula was fitted by eye, rather than a proper statistical model. That did not stop it becoming exercise-science orthodoxy.
Newer research studies in recent decades, based on more rigorous statistical analysis, tend to find that the age-related decrease in maximum heart rate is slower than the original formula implied. One commonly cited alternative, the Tanaka equation, first published in the Journal of the American College of Cardiology in 2001, estimates maximum heart rate as 208 minus 0.7 times age (173 for a 50-year-old).
These newer measures still fail to capture the huge amount of individual variability. One study, published in PLOS ONE in October 2025, compared seven different formulas with measured values in 230 people. It found that individual predictions were often off by as much as 20 beats per minute in either direction. That size of error could mean that what counts as moderate exercise for one 50-year-old may equate to vigorous exercise for another.
What should amateur athletes do? Consistency is key, says Professor Robergs. Pick one method and stick with it. That way you will know if your chosen training method is working, and can adjust if it is not.