What Is Max Heart Rate?
Maximum heart rate (MHR) is the highest number of beats per minute your heart can achieve under maximum physical stress. It's a biological ceiling — you literally cannot exceed it. Every heart rate training zone is calculated as a percentage of this number, making it the foundation of heart rate-based training.
MHR varies significantly between individuals. Age is the primary factor (it declines as you get older), but genetics also play a role. Two 30-year-olds can have max HRs differing by 30+ beats per minute. This is why age-based formulas are only estimates.
The Formulas
220 minus age (Haskell-Fox formula): The most common and most criticized. Developed in 1970 from a limited dataset. It tends to overestimate max HR for younger people and underestimate for older ones.
208 minus 0.7 × age (Tanaka formula): More recent research suggests this is more accurate, especially for people over 40. A 2001 study found it predicted max HR better across age groups.
211 plus 0.64 × age minus 0.67 × age plus 0.05 × weight (Londeree formula): Incorporates age and body weight. More complex but not necessarily more accurate for most people.
Try our max heart rate calculator to see all three estimates.
How to Test It Yourself
If you want your actual max HR rather than an estimate, you need a field test. Warm up thoroughly (10-15 minutes), then run or bike as hard as you can for 3-4 minutes, with the last minute being an all-out effort. Your heart rate at the very end is your max HR. Do this on a day you're well-rested, ideally with a heart rate monitor.
Laboratory tests (VO2 max testing with a metabolic cart) give the most accurate result, but they're expensive and typically unnecessary unless you're a competitive athlete.
Use It to Train Smarter
Once you know (or estimate) your max HR, you can calculate your training zones. Zone 2 (the most important zone for building aerobic base) is roughly 60-70% of max. Zone 5 is 90-100%. Training in the right zones ensures you're working at the intensity that produces the adaptations you want.