Resting heart rate

Resting heart rate (RHR) is the number of heartbeats per minute at full rest, ideally measured supine after several minutes of quiet rest or upon waking, and is influenced by caffeine, illness, medications, and sleep. Trained individuals typically have lower RHR primarily through elevated vagal/parasympathetic tone, with increased stroke volume as a secondary cardiac adaptation. Epidemiological data (e.g., Aune 2017) link elevated RHR with higher cardiovascular and all-cause mortality, making it a simple biomarker of cardiorespiratory health and recovery.