The cardiovascular system is foundational to exercise, and our understanding of how it works and how things can go wrong is critical for the performance, success, and safety of our clients. Consultation with a medical professional and a physical is recommended before starting an exercise program to uncover the health status of the cardiovascular system (CVS) and whether it will be adversely impacted by exercise. Is this enough? Let’s explore some known cardiovascular diseases and issues, and the physiology behind them.
Covert Cardiovascular Culprits
Health physicals may miss CVS heritable conditions to include:
- Hypertrophic Cardiomyopathy (HCM) where the walls of the heart muscle thicken causing disruption of the heart’s electrical system, leading to fast or irregular heart beats (arrhythmias)
- Congenital coronary artery abnormalities that are abnormally connected. When the individual with this condition exercises the arteries become compressed decreasing proper blood flow to the heart
- Long QT syndrome–a heart rhythm disorder causing fast chaotic heart beats often leading to fainting and having increased risk of sudden death. (this can also be induced as a side-effect of medication)
Sudden death of an athlete may be related to any of the aforementioned heritable CVS conditions if not detected prior to engaging in competitive sports. While the condition of HCM can be controlled by surgical implant of a cardioverter-defibrillator, the aforementioned heritable conditions come with the physician’s advice to avoid competitive sports.
The endothelium is a single layer of cells that line the inside of the artery. Dr. Michael Greger, MD likens the endothelial cell layer to being the Teflon of the arterial wall, allowing blood/cells to move smoothly. The artery wall has three layers:
- the inner layer (intima): the endothelium that lines the lumen of the vessel
- middle layer (media): the smooth muscle cells and elastic fibers
- outer layer (adventitia) comprised of collagen fibers.
Cardiovascular Disease/Arterial Plaque
The food we eat directly correlates to the progression of fat streaks in the arteries which are reported to develop as early as the age of 10. These fatty streaks become plaque, a fatty wax-like substance that accumulates over time within the artery wall. As the “bad” cholesterol (LDL) deposits on the arterial wall, macrophages come to ingest the LDL forming foam cells.
The macrophages laden with LDL appear under the microscope as foam-like structures. Foam cells contribute to atherosclerosis by progressing to plaque, which over time becomes unstable, i.e. ruptures the lining of the artery wall. Plaque progression within the wall of the artery causes the intima surface of the artery to bulge into the lumen (the hollow of the artery).
The plaque is composed of lipids, cell debris, smooth muscle cells, collagen, calcium and appears as a white/yellowish bulge within the wall of the artery. Calcification can occur in the intima or media layers of the arterial wall. As plaque grows it will break through the surface causing the body to respond by forming a blood clot. If the clot breaks away it becomes stuck in the artery that feeds the brain or heart and leads to either a stroke or heart attack, respectively.
According to William C. Roberts, editor of the American Journal of Cardiology, the one critical risk factor for atherosclerotic plaque is low-density-lipoproteins (LDL). He suggests removing processed food as well as animal and dairy products to reduce LDL. Likewise, excess white sugar is detrimental causing advanced glycation end (AGE) products that cause cellular damage leading to diabetes, heart disease, kidney failure, Alzheimer’s, all leading to premature aging. Specifically, AGEs will cause oxidative stress and chronic inflammation to our arteries.
AGEs are the covalent attachments of sugars to proteins or lipids. Noteworthy, regarding plaque and its potential to rupture is inflammation caused within the body by processed food, sugar and trans fats, lending to the recommendation of a Mediterranean Diet.
Detecting Narrowing of the Arteries
A CT Scan of the heart and/or MR/PET (Magnetic Resonance/Positron Emission Tomography) scanning can detect artery dysfunction. The MR/PET has lower radiation exposure.
William Fallon says in Life Extension issue Oct 2005: “Many doctors consider radiation from medical X-Rays to be harmless. However, a new National Academy of Sciences report confirms what Life Extension has long argued: that any amount of radiation has a potential to damage DNA, increasing the risk off certain cancer and atherosclerosis.” Further, in the same publication is information from John W. Gofman, MD, PhD, professor Emeritus of Molecular and Cell Biology at Univ. of California, Berkeley. Dr. Gofman notes: “radiation damages DNA in the arteries. The radiation-induced changes create a cancer-like phenomenon in the arteries known as atheroma. Dr. Gofman believes the integration between atheroma and lipids blocks arteries and causes blood clots.”
What can be done?
In the follow-up article to this blog, we will discuss possible modalities in reversing arterial plaque and the damage it causes, although there are varying opinions on this matter. There are two camps: One believes plaque cannot be reversed, only controlled; the other claims that atherosclerosis can indeed be reversed with both medication and lifestyle changes.