By Rachel A. Gioscia-Ryan, @RGRunPenguin and Zachary Clayton, @ZachSClayton, University of Colorado Boulder, US
Ageing is a broad concept defined in different ways depending on the type of scientist you ask. There are several ways our bodies can age on a molecular level. Changes to our blood vessels are an important component of ageing because blood flow around our body is crucial to making sure oxygen and nutrients are delivered, waste is cleared, and so our cells are nourished.
These alterations in our blood vessels result in what is called vascular ageing (the vasculature is the technical term for the network of our blood vessels). Vascular ageing primarily means that our blood vessels stiffen and are less able to dilate.
Specifically, with advancing age, there is stiffening of large elastic arteries (e.g., the aorta and carotid arteries) which is highly associated with other diseases of aging such as Alzheimer’s Disease and related dementias, as well as kidney disease and Type 2 diabetes mellitus.
Furthermore, impaired ability to dilate (called vasodilation) occurs as a result of a reduction in biologically available nitric oxide, the primary vasodilatory molecule produced by endothelial cells (single layer of cells lining the inner wall of our blood vessels).
Collectively, this is referred to as vascular endothelial dysfunction, which is an initiating step in the progression of atherosclerosis (the scientific term for the “clogging” of arteries due to plaque build-up).
In humans, we know that vascular ageing is influenced by individual lifestyle factors such as diet and physical activity, but how these factors interact with advancing age and impact vascular health is not fully understood.
The Western-style diet, characterized by high levels of saturated fat and sugar, and low levels of fibre and nutrients, is popular in developed and developing countries and has been linked to increased heart disease risk. Furthermore, this particular dietary pattern may be viewed as a model of accelerated vascular aging, such that age-related vascular dysfunction can occur faster than that observed while consuming a “healthy” diet (low levels of saturated fat and sugar, and high levels of fibre and nutrients).
Although dietary patterns are frequently maintained over the course of adult life, there is little information about how consumption of a Western-style diet interacts with the changes that occur to arteries with primary aging (the processes of ageing that are not due to disease nor poor health).
Regular aerobic exercise, colloquially referred to as cardio, has numerous established health benefits, including decreasing heart disease risk, in part because of the beneficial effects on the function of our blood vessels.
Experiments in mice have shown that aerobic exercise protects blood vessels when they are fed a Western-style diet at a young age. Other experiments have shown that voluntary wheel-running (a model of aerobic exercise), at an older age in mice, also protects against the negative effects of a Western-style diet.
Recently, our study published in The Journal of Physiology, examined whether exercise performed over the course of the lifespan can protect arteries from the combined stressors of ageing and chronic consumption of a Western-style diet in male mice. This was the first study to look across the entire adult lifespan, rather than focusing on either younger or older mice.
The study found that lifelong aerobic exercise prevented vascular dysfunction, due to chronological aging and also the Western-style diet administered to the mice, across the lifespan. This protection appeared to be mediated by limiting vascular mitochondrial oxidative stress and inflammation.
The key results of the study illustrate: 1) the temporal impairment of vascular function over the lifespan in mice, and acceleration and exacerbation of that dysfunction when animals consumed a Western-style diet; 2) the remarkable protective effects of voluntary aerobic exercise; and 3) the underlying mechanisms by which chronological aging, Western-style diet-mediated accelerated vascular aging and aerobic exercise influence vascular function over the course of the mouse lifespan.
Our study demonstrates:
- that the consumption of a Western-style diet accelerates the rate in which blood vessels age
- the protective effects of consistent aerobic exercise on the vasculature in the setting of normal chronological aging versus aging while consuming a Western-style diet
Taken together, our results implicate the importance of early adoption and maintenance of healthy dietary patterns and physical activity to maintain vascular function throughout the lifespan and likely reduce the risk of developing heart disease.
The perspective pieces written about this research article include an editorial and a Journal Club article, both published in The Physiological Society’s journal The Journal of Physiology.
The authors note that a study of this magnitude requires a large workforce and they would like to sincerely thank every member of the Seals Laboratory that assisted with this project.
Please note that all views expressed on The Physiological Society’s blog reflect those of the author(s) and not of The Society.