University of Missouri School of Medicine researchers have found that reducing daily physical activity for even a few days leads to decreases in the function of the inner lining of blood vessels in the legs of young, healthy subjects, causing vascular dysfunction that can have prolonged effects.

Paul Fadel, associate professor of medical pharmacology and physiology, and John Thyfault, associate professor of nutrition and exercise physiology, also found that the vascular dysfunction induced by five days of inactivity requires more than one day of returning to physical activity and taking at least 10,000 steps a day to improve.

“We know the negative consequences from not engaging in physical activity can be reversed,” said Fadel. “There is much data to indicate that at any stage of a disease, and at any time in your life, you can get active and prolong your life.”

Diabetes and cardiovascular disease risks

“Inactivity is typically going to lead to people being overweight and obese,” said Fadel. “The next step after that is insulin resistance, which leads to Type 2 diabetes and cardiovascular disease.”

According to the Centers for Disease Control and Prevention, more than 29 million Americans are living with diabetes. That number is expected to continue to increase: the CDC estimates one-third of people born after 2000 will have Type 2 diabetes in their lifetimes.

“The best treatment is to become more active, and our research lends proof to that concept,” Fadel said. “If you do not realize how harmful sitting around all day and not doing any activity is to your health, this proves it.”

The researchers studied the early effects on the body’s blood vessels when someone transitions from high daily physical activity — 10,000 or more steps per day — to low daily physical activity, less than 5,000 steps per day. Five thousand steps is the national average, but only half of the daily recommendation from the U.S. Surgeon General.

The research was published in November (2013) in the Journal of Applied Physiology and in September (2014) in Medicine and Science in Sports and Exercise. The research was supported in part by National Institutes of Health grants, an ACSM Foundation Research Grant from the American College of Sports Medicine, and an American Heart Association Pre-Doctoral Fellowship.