Taking breaks from sitting — such as getting up and walking around for a couple of minutes — was not linked to lower levels of liver fat or insulin resistance, according to a new study published in the journal Diabetologia.
It’s well known that physical activity is good for your cardiovascular and metabolic health, especially for people with diabetes. Greater activity is linked to fewer blood glucose spikes, and may help prevent health problems down the road like peripheral neuropathy and dementia. There is also some evidence that being sedentary — sitting for extended periods — is bad for you, at least in some situations. Greater sedentary time is linked to the risk of developing foot ulcers in people with diabetic peripheral neuropathy, and it’s even tied to a greater risk for stroke in less active younger adults. But there has been less research on sedentary time than on physical activity, so researchers are still trying to understand how it relates to different aspects of health.
For the latest study, researchers in the Netherlands were interested in looking at how the timing of physical activity — specifically, whether it broke up periods of sedentary time — was linked to levels of liver fat and insulin resistance. Elevated liver fat and insulin resistance are both very common in people with type 2 diabetes, and are part of a pattern of metabolic problems that also often include obesity, high blood pressure, and abnormal blood lipid (cholesterol and triglyceride) levels.
The study participants were 775 adults with an average age of 56 and an average body-mass index (BMI, a measure of body weight that takes height into account) of 26.2, which falls in the category of overweight. Each participant wore an activity tracker for four consecutive days and nights, and were told to carry on with their usual activities during this time. Sedentary time was defined as time in a resting state other than sleeping. Participants were also categorized as being most active in the morning (6 a.m. to noon), afternoon (12 p.m. to 6 p.m.), or evening (6 p.m. to midnight). Participants also had their liver fat and insulin resistance measured.
Amounts of sedentary time not linked to liver fat or insulin resistance
The researchers found that total sedentary time was not linked to either liver fat or insulin resistance, while taking more breaks from being sedentary was actually linked to higher levels of liver fat. Getting more moderate to vigorous physical activity, on the other hand, was linked to less insulin resistance, but not to liver fat levels. Participants who were most active in the afternoon or evening tended to have lower insulin resistance than those who were most active in the morning, or who spread their activity evenly throughout the day.
The researchers concluded that greater physical activity, especially late in the day, was linked to lower insulin resistance, while taking breaks from being sedentary was not linked to lower levels of insulin resistance or liver fat. Further studies, they wrote, should examine whether the timing of physical activity has any effect on whether people develop type 2 diabetes, since insulin resistance plays a key role in its development.
Want to learn more about liver fat? Read “Diabetes and NAFLD” and “Preventing Fatty Liver Disease.” Want to learn more about insulin resistance? Read “Insulin Resistance: Your Questions Answered” and “Insulin Resistance: What You Need to Know.”