heartratelowering

Heartratelowering refers to processes or interventions that decrease heart rate, typically measured in beats per minute. It can describe physiological states such as resting bradycardia in trained athletes or sleep, as well as pharmacologic or procedural approaches that slow the heart.

Heart rate is governed mainly by the sinoatrial node and autonomic input. Heartratelowering arises from increased parasympathetic (vagal) activity, reduced sympathetic drive, or direct suppression of pacemaker activity. Endogenous factors such as endurance training or relaxation techniques can raise vagal tone and lower resting rate.

Common mechanisms and means include physiological adaptation from long-term exercise, sleep, and meditation; pharmacologic agents such as beta-blockers (e.g., metoprolol, propranolol), non-dihydropyridine calcium channel blockers (diltiazem, verapamil), and the If current inhibitor ivabradine; digoxin may also lower heart rate via enhanced vagal tone. Vagal maneuvers like carotid sinus massage can temporarily reduce HR in clinical settings.

Clinical use often aims to reduce heart rate in tachyarrhythmias, ischemia, or heart failure with reduced ejection fraction, or to control ventricular rate in atrial fibrillation. The goal is to balance rate reduction with preservation of adequate cardiac output.

Risks include symptomatic bradycardia, dizziness, or syncope, especially in older adults or those with structural heart disease. In athletes, a low resting heart rate can be normal but warrants evaluation if accompanied by symptoms.

See also: bradycardia, chronotropic agents, autonomic nervous system, sinoatrial node.