We’ve all heard how important physical activity is for managing diabetes, but a new series of studies shows just how vital exercise is to blood glucose control and just how little of it is necessary for benefiting health.
Sitting Increases Diabetes Risk
The first study, conducted by researchers at the University of Leicester in the United Kingdom, involved 500 men and women age 40 and older. The investigators established the length of time the participants spent sitting over the course of a week and also checked their levels of various chemicals associated with diabetes and metabolic function.
The researchers found that women (but not men) who spent the longest time sitting each week had higher blood levels of insulin, as well as of C-reactive protein, leptin, and interleukin-6 (all markers of inflammation), indicating that they were at increased risk of developing Type 2 diabetes. According to lead study author Thomas Yates, PhD, “Women who meet the national recommendations of 30 minutes of exercise a day may still be compromising their health if they are seated for the rest of the day.”
Inactivity Linked With Postmeal Glucose Spikes
Another study, this one conducted at the University of Missouri, sought to determine the effects of inactivity on the risk of disease. Although previous research has indicated a link between lack of movement and conditions such as heart disease and Type 2 diabetes, scientists have not been able to fully determine whether it is the inactivity itself that increases the risk of these conditions or if there are other factors at play, such as metabolic or lifestyle issues.
To get around this problem, researchers recruited a group of healthy, active young adults for their experiment. The participants were outfitted with continuous glucose monitors, asked to log their meals and snacks in detailed food diaries, and also given pedometers and activity-monitoring armbands to track how many steps they were taking each day.
For the first the first part of the study, the volunteers were told to live normally, walking and exercising as usual. Each exercised roughly 30 minutes per day and averaged a total of nearly 13,000 steps per day. According to the data from their continuous glucose monitors, their blood glucose levels did not spike after meals during this period.
For the second part of the experiment, the participants were told to cut back on activity so that their step count would fall to under 5,000 steps each day — less than half of their usual number of steps. During this portion of the experiment the step count fell to an average of 4,300 steps per day and exercise dropped to under three minutes each day. They continued to eat the same meals and snacks as in the first three days of the experiment. This time, however, their blood glucose levels did spike after meals, increasing by roughly 26% compared to when the participants were moving more. And these blood glucose peaks grew slightly each day.
Just a Little Movement Goes a Long Way
A third study, this one from the Baker IDI Heart and Diabetes Institute, had some good news to report. This research looked at 19 overweight and obese adults ranging from 45 to 65 years old. The participants were given a glucose-rich drink and randomly assigned to either uninterrupted sitting, sitting broken up by two minutes of light-intensity walking every 20 minutes, or sitting broken up by two minutes of moderate-intensity walking every 20 minutes. Each participant was assigned to each group at some point during the course of the study.
The researchers found that interrupting the sitting with light- to moderate-intensity walking significantly improved the participants’ blood glucose response to the study drink, and that walking at a light pace was just as effective as walking at moderate pace. According to lead researcher David W. Dunstan, PhD, “What this study is showing is that people who sit for long periods, like office workers and call center staff and drivers, could improve their health by simply breaking up their sitting time with frequent activity breaks… If we introduced the activity breaks, it lowered glucose levels by about 30%.” He suggests standing up at least every 30 minutes.
In sum, as John P. Thyfault, PhD, lead author of the second study, notes, “You don’t have to run marathons. But the evidence is clear that you do need to move.”
To learn more about these three studies, read the articles “Diabetes Risk From Sitting Around,” “Research Shows Inactivity Leads to Glucose Spikes,” and “Standing Up From Your Desk Every 30 Minutes Can Avoid Diabetes by 30%,” or see the studies’ abstracts in, respectively, the American Journal of Preventive Medicine, Medicine & Science in Sports & Exercise, and Diabetes Care.