Calcium channel blockers are a class of medications designed for the treatment of high blood pressure, chest pain and irregular heartbeats, explains the Texas Heart Institute. These drugs' method of action, the main purpose of which is to block some of the calcium in the blood from entering into the heart muscle, may affect exercise tolerance.
Method of Action
The Texas Heart Institute explains that calcium channel blockers work by slowing "the rate at which calcium passes into the heart muscle and into the vessel walls. This relaxes the vessels. The relaxed vessels let blood flow more easily through them, thereby lowering blood pressure."
Significance
The heart muscle is different from all other muscles of the body in that not only is it capable of contraction, it is also able to conduct electricity, as explained in the "New World Encyclopedia." Reasoning stands that if calcium channel blockers work by slowing the entry of calcium into the heart muscle, other muscles of the body must be similarly affected. An article in a 1987 "Journal of Clinical Pharmacology" by Borje Johansson relates, "The troponin-tropomyosin system associated with the actin filaments is the best known of the calcium control systems. It operates, for instance, in vertebrate skeletal and cardiac muscles." This means that the system for muscle contraction in both cardiac and skeletal muscle both function by the same physiological principle.
Expert Insight
An April 2010 article in the "The Physician and Sportsmedicine" by Chad Asplund of Ohio State University's Department of Family Medicine, Division of Sports Medicine, provides information on calcium channel blockers and exercise. Asplund states the health-care provider should prescribe a medication which has both "favorable effects on blood pressure and minimal detrimental hemodynamic change during exercise." In regard to particular classes of medication, the author recommends, "Evidence supports that the medications with the most favorable effects are angiotensin-converting enzyme inhibitors, calcium channel blockers, alpha-blockers, and cardiac-selective beta-blockers."
Prevention/Solution
Causes of hypertension vary, and many times the exact cause of hypertension is unknown. Exercising, obtaining and maintaining a healthy weight, smoking cessation and stress reduction are four lifestyle changes recommended by Mayoclinic.com for the health of your heart, arteries and hypertension. It is conceivable that if you improve your lifestyle and health habits, there may come a time when your health-care provider feels your hypertension is controllable without prescription medication.
Considerations
William B. Jeffries, Ph.D., an investigator in hypertensive research for more than two decades, provides this information about specific calcium channel blockers: " Some calcium channel blockers also decrease exercise tolerance, such as verapamil and diltiazem." Additionally, in response to a question about which antihypertensive medication would be the least likely to cause electrolyte imbalance and dehydration for a cyclist and the recommended time of day to take the medication, Dr. Jeffries stated, " I think if it were myself, I would be inclined toward a dihydropyridine calcium channel blocker such as amlodipine. If taken once per day, it would probably be best at bedtime."
References
- Texas Heart Institute: Calcium Channel Blockers
- New World Encyclopedia: Cardiac Muscle
- Journal of Clinical Pharmacology: Calcium and Regulation of Contraction: A Short Review
- "The Physician and Sportsmedicine": Treatment of Hypertension in Athletes: An Evidence-Based Review
- All Experts: Hypertension
