As life expectancy increases in the world, centenarians—people who have celebrated their 100th birthday—have become increasingly common. Scientists now have more data related to changes that accompany aging than ever before. One thing the data show is that cardiac (heart) muscle must stay strong and, most importantly, resistant to fatigue for our heart to pump blood for up to 100 years.
To demonstrate the work your heart needs to do over the course of a century, take your pulse to estimate how many times your heart beats per minute. For most people, this number will be somewhere between 60 and 90 beats per minute. Now multiply it by the number of minutes in one year (525,600). Multiply the resulting number by 100. The number you end up with is how many times your heart would beat in your lifetime if you live to be 100. Pretty amazing.
In addition to your heart staying strong, your blood vessels need to be in top shape to help you become a centenarian. One way doctors can see how healthy your blood vessels are is to measure your flow-induced dilation.
When your heart pumps blood, it rushes through the blood vessels and acts on their innermost layer of cells (endothelial cells). Endothelial cells release chemicals that interact with the second layer of the blood vessel wall which contains smooth muscle cells. These chemicals cause the vessels to widen. This is called vasorelaxation or vasodilation. The entire response of the blood vessels is called flow-induced dilation.
My lab studied why flow-induced dilation changes from early childhood through healthy adulthood, and how it’s different in heart disease. My colleagues and I showed that different enzymes play a role in blood vessel dilation in children compared with healthy adults. In people with coronary artery disease (CAD), fatty plaques clog the vessels to obstruct blood flow. People with CAD also often have chronic inflammation, which makes the mitochondria (the “powerhouse” of the cell) produce free radicals. Free radicals damage cells and speed up aging. Hydrogen peroxide, a type of free radical, takes over regulation of flow-induced dilation in people with CAD. In other words, people with this form of heart disease have obstructed blood flow because free radicals have damaged their blood vessels. Cardiovascular disease, including CAD, is a leading cause of death in the U.S. and can certainly stand in the way of living your longest life.
Knowing what factors are responsible for controlling flow-induced dilation helps medical professionals develop balanced treatment plans to keep the blood vessels healthy in people of all ages. This knowledge might even help you live to be 100!
Natalya Zinkevich, PhD, teaches anatomy and physiology courses at Carroll University in Waukesha, Wisconsin. She studies vascular biology with a focus on human health and disease at the Cardiovascular Center of the Medical College of Wisconsin.