// minds behind maths

Martti Karvonen

1918–2009 · Exercise physiology

Martti J. Karvonen was a Finnish physiologist whose work on exercise intensity gave rise to the heart-rate-reserve method. Rather than working from maximum heart rate alone, it uses the gap between maximum and resting heart rate, so training zones reflect individual fitness. The approach is now a staple of cardio training and the heart-rate features on modern fitness watches.

Source: Wikipedia — Heart rate

Formulas that trace back to Martti Karvonen