Work out resting heart rate fitness instantly with clear inputs, formula shown and shareable results.
A low resting heart rate usually reflects a strong, efficient heart pumping more blood per beat. Heart rate reserve - maximum minus resting - is the working range available for exercise, and it widens as fitness improves. The Uth-Sorensen estimate VO2max = 15.3 x MHR/RHR turns the ratio into a rough aerobic capacity figure.
Heart rate reserve
HRR = MHR - RHR
Uth-Sorensen VO2 max
VO2max = 15.3 x MHR / RHR
This is an estimate from population-average equations, not a medical or diagnostic assessment. Individual results vary with genetics, training history and technique. Seek advice from a qualified coach or clinician before making significant changes to training.
First thing in the morning, still lying down, before caffeine. Readings taken during the day are typically 5-15 bpm higher.
Often incomplete recovery, illness, dehydration or poor sleep. A rise of 5-10 bpm above your norm is a common signal to ease off.