It’s no secret that exercise is important. It’s built into guidelines issued by the National Institutes of Health—at least two-and-a-half hours a week of moderate intensity exercise, such as brisk walking.
Not so fast, said Marc Hamilton, a pioneer in the growing field of inactivity physiology.
Here’s the better news: There are other things you can do to improve your health. That’s important, especially since fewer than 10 percent of Americans meet those exercise guidelines.
“Sitting is very hazardous behavior,” said Hamilton, director of the Texas Obesity Research Center at the University of Houston. “It leads to more issues than walking across the street, where you might get hit by a truck.”
Hamilton is one of the world’s leading biomedical scientists studying what happens inside the body when people are too sedentary, and he says there are no easy answers. Even intense bouts of exercise can’t undo damage caused by hours of sitting and inactivity.
He offers this analogy: People can’t thrive if they drink water only once a day. The body’s thirst for metabolic activity is no different.
Clearly, there is something special about remaining active throughout the day. That’s been clear for a decade—Hamilton began his research in the 1990s—but people in the Western World are as sedentary as ever, tethered to our cell phones and 100-channel televisions. The average American sits between 10 and 12 hours a day.
So far, however, there are no public health recommendations targeting that sedentary lifestyle.
That’s where Hamilton comes in. He was a founder of the field, which has spread to thousands of research labs all over the world, and much of his research has focused on lipoprotein lipase, a genetic enzyme involved in cardiovascular and a number of metabolic diseases. He discovered the enzymes are present in far higher concentrations in the soleus muscle—found in the lower leg and involved in standing and walking—than in other muscles.
Lipoprotein lipase, or LPL, is “a vacuum cleaner for fat,” he said. Sit down, and LPL levels plummet.
Without the “vacuum cleaner,” the risk skyrockets for obesity, diabetes, high cholesterol and other diseases linked to sedentary lifestyles as muscles lose the ability to convert blood glucose to energy and the fat instead travels to the liver, the coronary arteries and adipose tissues.
Hamilton, a professor in the UH department of health and human performance, hasn’t recommended quick fixes, such as standing desks or gimmicky reminders to fidget while you sit. He is waiting for results from his lab, where people come to have their oxygen levels, blood flow and a variety of chemical markers measured at rest and after specific activities designed to be safe for all kinds of people to do anywhere and any time.
He also works in the community, meeting with people at home and at community centers in Houston’s Third Ward and Fifth Ward. By working with people individually—showing them the results of blood tests that demonstrate the risks of inactivity—he is changing lives one at a time.
His next goal is even loftier. “We’re a university with a vision to make an international impact,” he said.
A rented space near Houston’s Galleria serves as hub for meeting with physicians, insurance executives, corporate leaders and individuals passionate about optimizing their own health with the latest medical advances. Employee health and public health affect the bottom line and the broader economy, and Hamilton is enlisting the business and medical communities to spread the word that inactivity can be deadly.
Despite statistics that might suggest this is a losing battle, Hamilton is just getting started.
“There is so much room for improvement in human health; it’s unbelievable,” he said. “I’m not pessimistic at all.”