The Dangers of a Sedentary Lifestyle

The Harvard School of Public Health says that 9 out of 10 cases of type 2 diabetes could be prevented by not being overweight, not smoking, and regularly exercising. However, a new factor has been added to the list of things that you can do to prevent diabetes: avoid extended periods of sitting.

This is why the American Diabetes Association has started a "Get Fit Don't Sit" Day, as research has shown that breaking up periods of inactivity is one of the most powerful weapons in preventing type 2 diabetes. They recommend getting up at least every 90 minutes, though many researchers recommend even more frequent activity, getting up every 20 minutes.

A 2015 publication in the Annals of Internal Medicine reports that a sedentary lifestyle is linked to a 91% increased risk of developing type 2 diabetes. And for many people, that's a big problem. The World Health Organization estimates that 95% of the world’s adult population is inactive. The Bureau of Labor Statistics, in 2011, shows Americans over the age of 15 watched almost 3 hours of TV per day on average. According to Emma Wilmot, a Clinical Research Fellow in Diabetes and Endocrinology working at the Leicester Diabetes Centre, referring to a study by the University of Leicester, "The average adult spends 50%-70% of their time sitting, so the findings of this study have far-reaching implications."

A 2013 study published in the International Journal of Behavioral Nutrition and Physical Activity surveyed 63,048 middle-aged Australian men about how long they sit during an average day as well as diagnoses of any chronic diseases, including type 2 diabetes. The result: the more time the participants sat, the higher the risk for type 2 diabetes and other chronic diseases. Additionally, even among the men who exercised regularly, they were still at a higher risk for diabetes if they sat for more than 4 hours a day. Richard Rosenkranz, PhD, study co-author and assistant professor of human nutrition at Kansas State University, concludes, "What this study found, and what other studies have found over the last five years, is that sitting time is an independent risk factor. Even if you get 30 minutes of exercise every day, you are still at risk if you sit for more than 4 hours."

And it’s not just diabetes. Sitting for more than 6 hours a day increases the men's risk for cancer, heart disease, and high blood pressure. And there's now interest among researchers in the relationship between a sedentary lifestyle and dementia, as well as depression. And some people report that when they stop sitting for extended periods of time, they experience less neck and back pain.

Dr. Rosenkranz asserts that sitting time may be why men get more chronic diseases than women (such as type 2 diabetes and heart disease). "Traditionally, since childhood, men have spent less time doing housework or child care," said Rosenkranz. "That may mean they have had more uninterrupted sitting time."

A 2008 Australian study in the Official Journal of the American College of Sports Medicine of people who were getting the recommended amount of exercise found that the more television they watched, the higher their blood glucose levels and blood pressure, and the larger their waist circumferences. The result: an increased risk for type 2 diabetes and heart disease.

A 2007 study showed that kids with type 1 diabetes who watched more television tended to have higher blood glucose levels.

Melanie Davies, Professor of Diabetes Medicine at Leicester, is a director of the National Institute for Health Research's Leicester-Loughborough Diet, Lifestyle and Physical Activity Biomedical Research Unit, explains that a study she participated in has important implications for health care professionals, "Being sedentary is common and dangerous for our long term health, particularly for diabetes and cardiovascular disease, and that this link appears to be over and above other lifestyle factors such as our diet and physical activity."

Dr. Joel Fuhrman, Director of Research for the Nutritional Research Foundation, notes, "Exercise and standing cannot compensate for and undo the dangers of eating unhealthily. People still need to eat healthily to expect a healthy play-span and lifespan."

How Sitting Increases Your Risk of Type 2 Diabetes

One theory about why extended periods of sitting put you at a higher risk for type 2 diabetes is that your body needs to work harder to absorb sugar and make insulin when sitting. That can put too much stress on the cells that make insulin, and that may be an important diabetes risk factor.

Marc Hamilton, Ph.D., of the Pennington Biomedical Research Center in Baton Rouge, La., studies a human enzyme called lipoprotein lipase that gets fat out of the blood and into the muscles for use during activity. According to Diabetes Forecast, he found that inactivity dramatically suppresses the enzyme, which leaves fat in the blood, potentially increasing the risk of heart disease, or that the fat will be stored in the body.

How to Reduce Your Risk

According to Dr. Hamilton, frequent minor movements, such as standing and walking, but not necessarily vigorous exercise, seems to be the best way to keep lipoprotein lipase working properly. "Sitting too much is not the same as exercising too little," says Hamilton.

"It may be that a prolonged period of very low energy expenditure is the key factor," Rosenkranz said. "All you need to do to reduce the risk of prolonged inactivity is stand up and walk slowly. You don't need exercise, just some increased activity."

David Dunstan, Ph.D., head of the Physical Activity Laboratory at Baker IDI Heart and Diabetes Institute in Victoria, Australia studied whether breaks in sedentary time, even short ones, can help people avoid the negative effects of sitting. In a 2008 study, Dunstan tracked the activity of a group of people who wore accelerometers for a week. He found that, no matter how much time they spent exercising or sitting, people who moved more frequently were thinner and had lower blood glucose levels than those who sat for extended periods.

Dunstan studied these mini breaks in overweight and obese adults in an office environment. Some participants sat all day, while others got up every 20 minutes to walk for 2 minutes, either walking slowly or at a moderate pace. Dunstan reported in a 2012 article in Diabetes Care that the breaks lowered blood glucose levels after meals, no matter how fast the participants walked. "The muscle contraction itself—and not intensity—is the important factor," says Dunstan.

According to the Harvard School of Public Health, every 2 hours you spend sitting while watching television increases your risk for type 2 diabetes by 14%. One way to counteract this is to get up and move whenever a commercial comes on.

Dr. James Levine, Professor of Medicine at the Mayo Clinic, is credited with the quote, "Sitting is the new smoking." He's a big proponent of standing desks, treadmill desks, and any other strategies to keep people moving throughout their day.

Dr. Fuhrman notes that people who are overweight often have poor exercise tolerance, and food addictions require a comprehensive approach that includes counseling and abstinence from processed foods.