With commentary by lead study author Julianne van der Berg, a Ph.D. candidate in social medicine at Maastricht University in the Netherlands.
It is well known that exercise can help prevent and manage diabetes, but researchers have begun to look more closely at the risks of being sedentary.
Recent studies have found that being sedentary, such as sitting at a desk all day or spending too many hours in front of the TV or computer screen, has been associated with a number of risk factors for diabetes and metabolic syndrome, including larger waist circumference, high cholesterol, and high triglyceride levels.
Now, a new study from the Netherlands has found that people who were more sedentary were more likely to develop type 2 diabetes and metabolic syndrome than those who were less sedentary.
Up until recently, the research has focused on the benefits of exercise. Aside from helping you lose and maintain weight, exercise can help maintain blood glucose levels, help insulin absorb glucose into your body’s cells, and help insulin or diabetes medications work more effectively. But exercising for 30 or 45 minutes a day may not be enough to counter all of the negative effects of sitting at your desk or watching TV for hours on end.
Researchers wanted to see just how great a role sedentary behavior plays in the risk of type 2 diabetes. They asked participants with normal glucose, impaired glucose and diabetes to wear a device that tracked their sedentary behavior, rather than relying on self-reports of activity, which can be less reliable. They looked at the amount of time they were sedentary as well as the number of breaks people took from being sedentary.
The study found that one extra hour of sedentary time a day was associated with a 22 percent increased risk for type 2 diabetes and a 39 percent increased risk for developing metabolic syndrome. Those with type 2 diabetes had up to 26 more minutes a day of sedentary time compared to others. “Our findings suggest that sitting behavior may play a significant role in the development and prevention of type 2 diabetes,” says the lead author, Julianne van der Berg, a doctoral candidate in social medicine from Maastricht University in the Netherlands.
"The consequence of sitting for a long period of time is that there is little muscle use and thus, little energy burn, and the metabolic pathways regulating how we store blood sugars are less active and effective," says Avi Biswas, lead author of the Toronto study, a doctoral candidate at the University of Toronto and Research Analyst at Toronto Rehabilitation Institute. "Thus, we tend to have more sugars in our blood, store less, and over time this can contribute to an increased risk for developing type 2 diabetes."
Prior research has found that long periods of sedentary time was also associated with an increased risk for dying from all-causes including cancer and cardiovascular diseases, an increase risk for certain forms of cancer, cardiovascular disease and type 2 diabetes. One meta-analysis from the University of Toronto found that the largest association was with type 2 diabetes, with a 91 percent increased risk.
The Toronto study did find that exercise can reduce the risk of death from all-causes due to prolonged sedentary behavior, but only partially. “Our study found that those who were highly sedentary but also exercised had reduced their risk of death from all-causes by 30 percent as compared to those who were highly sedentary but also did not exercise enough,” says Biswas. “In other words, the risks still exist, but they’re much lower,” he says.
If you’re sedentary for many hours a day, going to the gym will definitely help, but the research suggests that you also need to interrupt that sedentary time.
To do this, you may need to find ways of replacing your sitting time with standing time or walking time. For example, try standing or walking during phone calls or invest in a standing desk. But just getting up to stretch may not help. “Sedentary breaks” won’t hurt but the Netherland study did not find that these types of breaks significantly change the risk of diabetes, though they appeared to lower the risk of metabolic syndrome. The point is to spend less time sitting and more time on your feet.
To do this, you may need to find ways of replacing your sitting time with standing time or walking time. For example, try standing or walking during phone calls or invest in a standing desk. “Sedentary breaks” won’t hurt but the Netherland study did not find that these types of breaks significantly change the risk of diabetes, though they appeared to lower the risk of metabolic syndrome.
Some ways to reduce your sedentary time: Take a five minute standing or walking break once every half hour or hour. Get up and move during your lunch break. If watching TV, playing video games, take breaks during every commercial or every half hour.
“While regular or high levels of physical activity seem to have protective effects on reducing sedentary risks, we believe there is sufficient evidence to suggest that a focus on promoting regular exercise and reducing sitting time to be a better public health message,” says Biswas.