Why is exercise good for our hearts? The Hidden Cardiovascular Benefit of Exercise
I think that we all know that exercise is good for us….right? Exercise stands as one of the most extensively studied interventions for improving our health and there is a wealth of evidence supporting its benefits across various health domains including cardiovascular, muscuskeletal, mental, and metabolic health to name a few. While most of us know that exercise is good for our health explaining why it is good often stumps many of us including health professionals. For this blog I will focus in on why exercise is beneficial for the cardiovascular system and why engaging in regular exercise is crucial for individuals with coronary artery disease.
It has repeatedly been shown that exercise is good for our hearts and in individuals with coronary artery disease who have had a heart attack, angioplasty, and/or bypass surgery, engaging in regular exercise has been shown to reduce cardiovascular mortality (the chance of dying from a heart-related cause) by over 20%, to reduce the occurrence of future cardiac events, and to lower the chance of being hospitalized in the future.
So what makes exercise so protective? What many of us are told is that in addition to increasing strength and fitness levels (which can be very important for individuals recovering from a myriad of heart issues not to mention prolonged hospital stays) exercise helps to optimize known cardiovascular risk factors such as obesity, diabetes, hypertension (high blood pressure), and dyslipidemia (high cholesterol). While regular exercise certainly increases the heart muscle’s strength resulting in significant improvements in cardiovascular fitness the effect it has on some risk factors is often small and does not account for the reduced mortality and lowered event rate that exercise achieves in those with cardiovascular disease.
Looking closer at the impact of exercise on cardiovascular risk factors research has shown that for individuals with hypertension exercise has been shown to achieve only modest reductions of systolic and diastolic pressures of about 5-7 mmHg. As for dyslipidemia, aerobic exercise has been shown to modestly lower bad cholesterol (LDL) by 3-6 mg/dl or 0.17-0.33 mmol/L. Considering that most cardiac patients are prescribed anti-hypertensive and cholesterol lowering medications, the ability to influence these risk factors to a major degree with the addition of an exercise program is questionable. In individuals with diabetes, exercise has been shown to improve blood sugar control and increase insulin sensitivity which is a fancy way to say that exercise helps the body’s cells to use blood sugar more effectively. This is a powerful benefit and the reason why all individuals with diabetes should engaged in regular exercise however again does not completely account for the mortality benefits that exercise has repeatedly been shown to achieve in cardiac patients.
So, if exercise’s benefits go beyond lowering cardiovascular risk by modifying the know cardiac risk factors what else is going on?…enter endothelial function.
To best understand the concept of endothelial function it warrants a quick step back to explain coronary artery disease. The hallmark of coronary artery disease is the accumulation of plaques and hardening of the coronary arteries otherwise knows as atherosclerosis. This process begins with damage to the endothelial lining which is a thin layer of cells that coats the inner most surface of the coronary arteries, and over time this can narrow the arteries and restrict blood flow to the heart. This reduction in blood flow can lead to a condition know as ischemia where the heart muscle does to get enough oxygen and in advanced stages plaques may rupture and the resulting blood clots can entirely block the artery leading to a heart attack.
When we exercise our heart rates increase and as the blood rushes through the coronary arteries the increased shear stress or force exerted by the increased blood flow on the endothelial cells acts as a catalyst for the production of a substance call nitrous oxide by the endothelium. Nitric oxide is a potent vasodilator (causes the arteries to widen), and diffuses into the smooth muscle cells of the arteries signalling them to relax and dilate. Beyond its role as a vasodilator, nitric oxide possesses anti-inflammatory and anti-thrombotic properties. By reducing inflammation and preventing excessive blood clotting, nitric oxide contributes to maintaining the health of blood vessels and preventing the development and/or progression of atherosclerosis.
The positive impact of exercise on endothelial function is not limited to a specific age-group or fitness level however to achieve the benefit the heart rate needs to increase and intensity is key. This is not to say that high-intensity exercise is the only way to enhance endothelial function as even moderate-intensity exercise such a brisk walking or cycling has been shown to elicit beneficial changes. That said, to improve endothelial health it is prudent to exercise at an intensity that at least provokes a mild challenge to your breathing.
The cardiovascular benefits of exercise extend far beyond the visible outcomes like increased endurance, improved cardiovascular risk factor profile, and a stronger heart. The intricate mechanisms at play, particularly the improvement of endothelial function through elevated shear stress and enhanced nitric oxide production showcases the positive impact of exercise on our cardiovascular system. As we lace up our sneakers or hop on our bikes, we are not just burning calories; we are investing in the long-term health of our hearts and blood vessels, ensuring a robust and resilient cardiovascular system for years to come.
The information in the blog is provided for informational and educational purposes only and does not constitute medical advice. The information is not a substitute for professional medical advice, diagnosis, or treatment. For questions please follow up with your healthcare professional.
