Regular Leg Movement Even More Important in Certain Environments, UNO Research Finds

Standing up and moving around is likely even more important depending on the environment where a person is sitting, according to a new study by University of Nebraska at Omaha (UNO) researchers.

While the negative health effects of prolonged sitting have been well-documented, this study newly examines how the air in the environments where people sit can make matters worse.

As people exhale carbon dioxide (CO₂) in an office space or another densely populated enclosed area, the level of CO₂ can soar up to five times the normal atmospheric level, impacting heart rate, blood flow, and other cardiovascular functions, particularly in the legs.

Researchers found that these effects are compounded by sitting in place for long periods of time. Prolonged sitting typically reduces microvascular function, which involves small blood vessels such as capillaries, as well as macrovascular function, which involves larger blood vessels such as veins and arteries.

The good news: A little movement and effort can go a long way toward protecting cardiovascular health.

In the study, 14 healthy young adults sat in chairs for two and a half hours. Two groups were able to move their legs every 30 minutes while remaining seated by using a small elliptical at their feet. One group actively pedaled on the elliptical while a second group’s ellipticals were moved for them. A third group remained seated and did not move their legs for the duration of the study.

Song-Young Park, Ph.D., assistant professor in the School of Health and Kinesiology, led the study in UNO’s Vascular Research Lab. “We used a novel approach in this study by testing all three groups in an environment with CO₂ levels similar to that of an office space or classroom. By tracking changes in heart rate, blood pressure, arterial stiffness, and function of the endothelial lining in blood vessels, we were able to see how different levels of activity impacted vascular function.”

As expected, the group of participants who remained seated and relatively motionless for the test experienced the greatest reduction of vascular function in their legs. Those who actively pedaled on the elliptical experienced significantly improved function of all blood vessels in their legs. Those who had someone else pedal the elliptical for them to move their legs experienced some improved function in only smaller blood vessels of leg muscle. Additionally, CO₂ exposure exacerbates the negative effects of prolonged sitting but active movement still improved blood vessel function.

Liz Pekas, a doctoral research assistant in UNO’s Vascular Research Lab, discussed how this research could impact everyday life. “For anyone working a desk job or taking a lengthy flight, it isn’t always possible or ideal to stand up and walk around,” Pekas said. “This research found that adding in some movement when seated for an extended period of time can help protect vascular function. Moving around can be as simple as tapping your foot, fidgeting, or even pedaling on an elliptical device.”

The full research article can be read in the American Physiological Society’s Journal of Applied Physiology.

This work was supported by a pilot award from the National Institutes of Health COBRE (P20GM109090), the NASA Nebraska Space Grant (NNX15AI09H and 80NSSC20M0112), the NASA Nebraska Space Grant Fellowship, The Sherwood Foundation (5444), the University of Nebraska at Omaha Graduate Research and Creative Activity (GRACA) grant, and the NIH National Heart, Lung, and Blood Institute Grant R00HL125756.