Final answer:
The formula 220 minus age is commonly used to estimate maximum heart rate (HR) during exercise.
Step-by-step explanation:
The formula 220 minus age is commonly used to estimate maximum heart rate (HR), which is a measure of the highest number of beats per minute the heart can reach during exercise. Maximum HRs are normally in the range of 200-220 bpm, but decrease as one ages. By subtracting the individual's age from 220, this formula provides an estimate of the maximum HR.