Ivabradine for Heart Rate Reduction During Exercise in Healthy Adults

Inclusion Criteria: * Healthy males and females aged 19-39 years, and 60-79 years * Engaging in regular aerobic exercise (e.g., running, cycling, swimming, hiking, field, ice, or racquet sports) at least once per week Exclusion Criteria: * History of any cardiovascular condition, including hypertension * Use of any chronic medication * History of any respiratory condition, including asthma * Smoking, including cannabis or vaping in the past year * History of diabetes mellitus, cancer, hepatic, renal or any other chronic illness * Seated blood pressure ≥130/90 or \<100/60 mmHg * Body mass index \<20 or \>32 kg/m2 * Non-sinus rhythm or abnormalities on 12-lead electrocardiogram (ECG) * Pregnant, breastfeeding, or women of childbearing potential not using appropriate contraception * Current or recent (past year) participation in \>150 minutes per week of moderate-vigorous intensity exercise (to avoid endurance training-related bradycardia) * Any condition that prevents vigorous exercise from being performed safely * Seated resting heart rate \<60 beats per minute * Prolonged QT interval (e.g., long QT syndrome) * Sick sinus syndrome, sino-atrial block or third-degree atrio-ventricular block * Use of strong cytochrome P450 (CYP3A4) inhibitors (e.g., nirmatrelvir and ritonavir, ketoconazole), which can increase ivabradine levels in the blood to potentially unsafe levels * Use of verapamil or diltiazem, which are moderate CYP3A4 inhibitors and also lower heart rate, posing a risk of excessive bradycardia when combined with ivabradine * Lactose intolerance, as ivabradine contains lactose * Known allergy/hypersensitivity to ivabradine or to any ingredient in the formulation or component of the container