Overweight people who spend long periods of time sitting – such as office workers – may benefit from even a few short two-minute breaks of light or moderate exercise during the day, according to a new study.
Australian researchers, writing in the journal Diabetes Care, found overweight and obese people who broke up long periods of time sitting down with a short walk or other forms of activity were able to maintain healthier levels of blood sugar and insulin.
This was particularly true after a high-calorie meal, according to scientists from the Baker IDI Heart and Diabetes Institute in Melbourne.
Lead researcher David Dunstan noted spikes in blood sugar can damage blood vessels and cause heart problems.
"This increases our susceptibility to heart disease,” he said, “so, we want to minimize these rises in order to improve our health outcomes. Our research has already shown that sitting for long periods can be hazardous to health. Sedentary behaviour is also a risk factor for chronic diseases, including some cancers."
For the study, researchers recruited 19 participants aged 45 to 65 who were overweight or obese. Each participant took part in three experiments designed to approximate working conditions of office workers.
In the first experiment, they had to sit for 5 hours with no break. In the second, they sat for the same length of time, but every 20 minutes they walked on a treadmill at a light-intensity pace for 2 minutes. In the third, they took a moderate-intensity exercise break three times an hour.
Glucose and insulin levels were then tested at the end of the 5-hour periods in each of the three experiments. Dunstan said researchers found the participants who interrupted their sitting time with regular activity breaks had a “30 percent improvement” in controlling blood sugar levels. They also noted little difference in benefit between high and moderate intensity activity:
“Interrupting sitting time with short bouts of light- or moderate-intensity walking lowers …glucose and insulin levels in overweight/obese adults,” they wrote. “This may improve glucose metabolism and potentially be an important public health and clinical intervention strategy for reducing cardiovascular risk.”