August 5, 2013
Arteries in the neck and chest are more important in determining walking speed than arteries in the leg.
Due to aging, many older adults experience more restricted blood flow in their legs, and researchers have wondered how lower blood flow affects walking ability. Recent research by a Texas Tech University scientist discovered arteries in a person’s neck and chest are more important in determining walking speed than arteries in the leg.
The study conducted by Joaquin Gonzales, an assistant professor in the Department of Health, Exercise and Sports Sciences, found stiffness in the large arteries located in the chest and carotid artery in the neck were more related to slow walking speed than the femoral artery in the leg.
Published in Clinical Physiology and Functional Imaging, the study determined if arterial stiffness relates to walking speed in healthy older adults. With his findings, new therapeutic strategies could be developed to improve physical function by focusing on vascular health in aging adults.
“To my surprise, the relationship between central arterial stiffness and walking speed remained significant after adjusting for age, body mass index, and resting blood pressure,” Gonzales said. “This is interesting because it means that the association between central arterial stiffness and walking speed is not explained by the older age of our participants, their body mass or because of high blood pressure.”
Walking speed is an important measure of physical function because it predicts disability and death in older adults.
Through an experiment with 21 adults ranging in age from 61 to 67, Gonzales’ research indicated vascular function in aging adults may diminish their ability to perform daily activities such as walking.
Two previous studies by other researchers focused on what arteries influence walking speed, but both studies involved adults with multiple disorders or diseases. To eliminate these confounding variables, Gonzales’ study only included adults free of cardiovascular disease and who were not taking medication that could influence their vascular function.
Participants completed a 400-meter walk test to measure walk speed. Arterial stiffness was measured using Doppler ultrasound and pulse wave velocity using arterial tonometry.
“An easy way to comprehend pulse wave velocity is bowling,” he said. “When a bowling ball is thrown on a hard surface it rolls fast. When the ball is thrown on a carpeted floor that provides cushion, the ball travels slowly. In the same way the bowling ball would travel on carpet, our arteries serve a role to dampen the force of blood when it is ejected from the heart. However, stiff arteries fail to dampen the pressure and force associated with blood flow, which can cause injury at small arteries – like those in the brain and kidney. Therefore, high pulse wave velocity reflects stiffer arteries.”
Because the heart is constantly beating, arterial stiffness with advancing age is unstoppable. However, Gonzales recommended tips to slow down the process.
“Other studies have shown that regular aerobic exercise can decrease the stiffness of arteries in older adults,” he said. “Diet is another important component as well. You want a diet high in natural nitrates, which increase the nitric oxide in the blood, relaxing arteries, and making them more flexible.”
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