Cardiovascular Disease

Most of the benefits of exercise affecting cardiovascular disease are actually reducing the risk factors for cardiovascular disease. Some major risk factors include: high LDL cholesterol, uncontrolled high blood pressure, obesity, diabetes, high C-reactive protein, atherosclerosis (Link to atherosclerosis module), etc. It has been shown for a long time however that exercise has healthy benefits on the cardiovascular system.

Link Between Exercise and Cardiovascular Health

It has been shown in studies for a long time that exercise correlates with better cardiovascular health. A study back in 1984 looking at Harvard alumni showed that post-college exercise correlates with low coronary heart disease risk. The alumni with sedentary lifestyles had a higher risk, even if they were varsity athletes in college. The overall conclusion to the study was that level of exercise is inversely proportional to total, cardiovascular, and respiratory mortality. This study looked at the benefit of exercise independent from other elements including smoking, obesity, hypertension and heredity.  

The Nurses' Health Study is an ongoing study, but a recent publication showed a similar result, but did not look at exercise independently. Instead, this study categorized nurses by several lifestyle factors, one of which was exercise. In the end, they concluded that women who didn't smoke, had a healthy BMI, had a healthy diet, and engaged in vigorous exercise had a 0.17 relative risk for coronary heart disease compared to all other nurses in the study. While it is unclear from this how much of the risk reduction is actually due to exercise, we can conclude that exercise does play some role in reducing risk.  

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Mechanisms

More recently, studies have looked at the mechanisms behind the benefits of exercise. Although a lot more information is known about the effects of exercise on the cardiovascular system, there are still a lot of questions to be answered. One study found that exercise relates to the levels of inflammatory markers. The study specifically looked at an older population, but it was still conclusive. They specifically looked at C-reactive protein, interleukin-6, and tumor necrosis factor alpha, all of which are inflammatory markers. Exercise was associated with low levels of all of these after controlling for body fat. A high level of all of these is associated with a high risk of cardiovascular disease, so reducing them is healthy for the heart.

Another primary mechanism is the functional activity of the vascular endothelium. The increase in exercise causes an increase in blood flow, which enhances the vasodilatory capacity of arteries. Specifically, it is nitrogen monoxide (NO) that is responsible for all of the benefits. Endothelium derived NO leads to inhibition of endothelial cell apoptosis, suppression of inflammatory activation, and an increase in the activity of oxygen-radical scavenging enzymes. These are the basic effects, but the full mechanism comes down to gene regulation which can be found in the article. The diagram below provides a summary.

 

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Special Cases and Risk Factors

This section is kind of messy. Too many bullets and not enought coherent explanation.

Many of the effects of exercise on the cardiovascular system depend on the study population and not all have found that exercise has a significant impact on the cardiovascular system. Below are summaries of studies looking at these various populations.

The Women's Health Study

https://www.jstage.jst.go.jp/article/circj/77/2/77_CJ-13-0007/_pdf

 

 

http://www.nejm.org.ezproxy.bu.edu/doi/full/10.1056/NEJMoa042135

 

 


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