Resting heart rate

Resting heart rate is the number of times the heart beats per minute at rest, measured on waking before getting out of bed.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 443.} Most adults fall between 60 and 80 beats per minute, though 60 to 100 can be normal.^{2Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 211.} Below 60 is classified as bradycardia and above 100 as tachycardia; women average 7 to 10 beats per minute higher than men.^{2Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 211.}

Endurance athletes tend to have lower rates because a trained heart pumps more blood per beat and needs fewer beats for the same resting output.^{3Viada, The Ultimate Hybrid Athlete, p. 64.} Viada describes these adaptations as tending to bottom out around 40 beats per minute.^{3Viada, The Ultimate Hybrid Athlete, p. 64.} Much lower rates are usually athletic bradycardia, often without symptoms but sometimes accompanied by dizziness on standing or general fatigue.^{3Viada, The Ultimate Hybrid Athlete, p. 64.}

In practice

• Count the radial pulse for a full minute after waking, before getting out of bed.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 443.} Use fingertips instead of the thumb, and avoid pressing hard at the carotid, which can artificially lower the reading.^{2Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 211.}
• Use resting heart rate in the Karvonen formula: as it falls with fitness, heart rate reserve rises.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 443.}
• Follow the trend: a waking rate that falls over time shows improving fitness, while a reading well above the client’s usual rate can signal overtraining and a need for rest or a health check.^{4Daniels, Daniels’ Running Formula, 4th ed., p. 77.}