Not Yet RecruitingEarly Phase 1

Ivabradine for Heart Rate Reduction During Exercise in Healthy Adults

Canada20 participantsStarted 2026-08-01

Plain-language summary

During exercise, working muscles require more oxygen. The heart meets this demand in two ways: by beating faster (heart rate) and by pumping more blood with each beat (stroke volume). Heart rate increases steadily with exercise intensity until exhaustion, but the amount of blood pumped with each beat tends to plateau at moderate intensities. Why the amount of blood pumped with each beat becomes limited before heart rate, however, is not well understood. Studying these mechanisms is difficult because most drugs that lower heart rate also affect how strongly the heart pumps, making it hard to separate the two effects. One medication that can help with this is ivabradine, which is used to treat people with heart disease who have high resting heart rates. It slows the heart rate without changing how strongly the heart pumps. This study will investigate whether ivabradine lowers heart rate during exercise in healthy younger and older adults, and whether a higher dose lowers heart rate more. The results will help us better understand how heart rate influences the heart's ability to supply oxygen to the body during exercise, and what limits the ability to exercise as people age. Participants will: * Attend three visits at SportsCardiologyBC in Vancouver * Complete a cycling exercise test at each visit to measure heart rate and how hard they can exercise * Take ivabradine (a heart-rate-lowering medication) before the exercise test at Visits 2 and 3 (a lower dose at Visit 2 and a higher dose at Visit 3) * Be monitored for side effects including slow heart rate, visual symptoms, and headache.

Who can participate

Age range

19 Years – 79 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

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 ris…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Heart rate, peak

Timeframe: Within 30 minutes of exercise onset

Trial details

NCT IDNCT07717710

SponsorUniversity of British Columbia

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2026-12

Contact for this trial

Stephen P Wright, PhD

604-806-9292 stephen.wright@ubc.ca

View on ClinicalTrials.gov More Healthy Adult trials