Exercise, Inflammation and Heart Disease

Top line summary

• Inflammation is a critical process in the development of heart disease

• Inflammation can be measured by hs-CRP, a blood test

• Exercise interacts with inflammation in surprising ways

• Heart rate variability might be a surrogate for inflammation

What does inflammation mean?

To simplify nearly a century of research: we first thought thought that plaque buildup had to do only with lipids and lipoproteins. We now recognize that in addition to this very important factor, small signaling molecules that tell our body to, for example, fight an infection, play a significant role in every step of plaque development, remodeling and plaque rupture leading to a heart attack.

How can we measure inflammation?

A general marker of inflammation in the body is called protein called C-reactive protein (CRP). CRP is produced in the liver in response to inflammation by the liver. High sensitivity C-reactive Protein (hs-CRP) is a special blood test that can indicate broadly whether there is active inflammation in the body. hs-CRP above a level of 2 mg/dL has been independently associated with heart risk, but the risk is probably somewhat linear, like it is for lipoprotein (a). In other words, the higher the level the worse the inflammation and higher the risk of disease.

Exercise affects inflammation

Early in a bout of exercise, inflammation markers are increased. However, long term habitual exercise training results in reductions in inflammation, and in levels of CRP.

Interestingly, some studies suggest that higher heart rate variability is associated with lower markers of inflammation as well. High hs-CRP is seen in patients with low HRV and those with higher resting heart rate. It would be very interesting to see further studies confirming this relationship, and I suspect that the mechanism behind the relationship may be due to the effects of exercise, which we know can increase HRV and may reduce hs-CRP.

Summary

Inflammation is a critical driver of heart disease, and can be measured with hs-CRP. Exercise is the most powerful (and most enjoyable) drug we have in combating heart disease. Habitual exercise appears to be associated with reduced inflammatory markers, and is undeniably good for your health. Some dat supports high HRV to be associated with lower CRP.

Acknowledgements

“Inflammation and cardiovascular disease: From mechanisms to therapeutics” Alfaddagh et al, American Journal of Preventive Cardiology, 2020

“Inflammation in Atherosclerosis-No Longer a Theory” Libby et al, Clinical Chemistry 2021

“The Effects of Physical Activity on Serum C-Reactive Protein and Inflammatory Markers” Kasapis and Thompson, JACC 2005

“Heart rate variability and circulating inflammatory markers in midlife” Alen et al, Brain, Behavior, & Immunity - Health 2021

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