The Impact of Cardiovascular Fitness on How the Cardiovascular System Reacts to Inflammation-A Possible Explanation for Why Being Fit Decreases Mortality

Dr. Jeffrey Sankoff is an emergency room physician, triathlete, coach, and host of the TriDoc podcast. He breaks down the latest in multisport science to help keep you educated, healthy, and fast!

Age brings with it a lot of positives; wisdom, maturity of thought and behavior, financial security to many, and the joys of parenthood and grandparenthood. But the aging process also brings with it important health consequences that as active endurance athletes we are always on the lookout for ways to forestall.

Cardiovascular disease (CVD) is the leading cause of death in the Western world and particularly burdens those who are older. Regular exercise is one of the well-known means by which the risk of CVD can be decreased.

• A growing body of research suggests that one of the important ways that exercise is protective is by how it affects our blood vessels.

• People who exercise regularly tend to have blood vessels that are less stiff and therefor offer less resistance to blood flow and this is better for the heart. 

The big question for scientists to this point has been why? What mechanisms are at work that cause these changes?

The Short Answer 👇

Inflammation has important impacts on the blood vessels and over time makes them stiffer. Regular exercise has been shown to reduce overall inflammation and mitigate the impact of inflammation on the blood vessels leading to improved overall cardiovascular health.

The Long Answer 👇

The inflammatory response is critical to fighting infection and to healing injuries. A complex interplay of a wide variety of cells, inflammation is mediated by a vast array of chemicals that are liberated both locally and systemically by those cells with wide ranging effects. These effects are integral to keeping us healthy but if unchecked can contribute to significant disease. For example, many auto-immune diseases like Lupus or Rheumatoid arthritis are simply the result of inflammatory processes that have run amok. Similarly, sepsis, a syndrome of unchecked whole-body inflammation in response to an infection is a major cause of morbidity and mortality in hospitals.

Research has revealed that even minor bouts of inflammation can have an impact on our blood vessels and how they respond to normal stresses. In an acute infection when inflammatory mediators are high, blood vessels become stiff and less responsive to endogenous vasodilators like nitric oxide.

When we are young, that stiffness resolves once the acute inflammatory process has resolved but over time as we age, there is a gradual decrement in the ability of the vessels to return to normal.

All of this is compounded by the effects of aging on the immune system itself. As we get older our immune system is changed in two ways: First, it becomes less capable of fighting off infections and so we are more susceptible to illness and second, the system is continually activated at a higher level than when we are young. That is to say that as we age, we have a higher and higher baseline level inflammatory state. This is frequently referred to as ‘inflammaging’.

The clinical effects of these two changes in conjunction with the established vascular changes seen with age result in older adults becoming more seriously ill more frequently from infection and their succumbing to CVD in the early phases of those infections. 

Exercise it seems can have a dramatic impact on all of this.

When compared to age matched controls who don’t exercise, older adults who exercise regularly have significantly lower levels of baseline inflammation. In addition, they have been shown to have a less exuberant response to infections and have blood vessel characteristics that are more comparable to young adults then to their sedentary peers.

Studies have also shown that when contracting an infection, older adults who do not exercise have a 33% higher risk of developing sepsis and an 87% higher risk of death when they do get septic demonstrating the important effects that exercise has on the immune system and the inflammatory response.

The physiologic rationale for all of this appears to be in how regular exercise lowers inflammation and oxidative stress and how that in turn improves the health of the vasculature and protects the heart. An additional benefit comes from tempering the responsiveness of the immune system. Much of this is speculative or extrapolated from research on parallel questions but the evidence is very compelling.

Previous experience has shown how regular exercise was protective from the most severe cases of Covid and from developing long Covid, again by means of decreasing the inflammatory response so this is along the same lines.

The take home point is clear; regular exercise has important benefits not just to well-being but to long term health and making it a part of your regular routine as you age can lead to a higher quality of life and longer life as well.

Train hard, train healthy

Lefferts EC, Ranadive SM. Vascular Responses to Acute Induced Inflammation With Aging: Does Fitness Matter? Exerc Sport Sci Rev. 2024 Apr 1;52(2):68-75