Each pulse at the wrist echoes a ventricular contraction. Heart rate is the number of times the heart beats per minute, normally between 60 and 100 at rest in adults.

Rate rises with exercise, fever, anxiety, and certain drugs, and falls with fitness, sleep, and some medications. Extremely slow or fast rates can reduce cardiac output and cause symptoms. Measurement is by pulse palpation, auscultation, or electronic monitoring. Rhythm regularity is assessed at the same time.

Target heart-rate zones guide exercise prescription. In hospital, continuous monitoring detects dangerous bradycardia or tachycardia early. Context matters: a rate of 50 may be normal in an athlete and ominous in a shocked patient.

• Number of heartbeats per minute
• Normally 60–100 at rest in adults
• Varies with activity, illness, and drugs
• Measured by pulse or electronic monitors