Background: Regularly interrupting sedentary behaviour has shown beneficial effects on glucose and insulin metabolism; however, it is unclear as to the minimal intensity and duration of activity that can decrease the negative effects of prolonged sitting. The aim of this study was to investigate the effects of spontaneous low level physical activity performed during two days of predominantly sedentary behaviour on postprandial metabolism.
Methods: Over a two day period, 17 participants sat continuously; 7.5 hours (h) on day one and 6.5 h on day two, except for obligatory bathroom breaks. Participants were fed three meals on day one and a high fat meal on day two. Blood samples were taken at 0 min only on day one, and 0, 30 and 45 min for the first hour, then hourly for 5 hours on day two. Responses for day two were calculated as area under the curve (AUC) and incremental area under the curve (iAUC) for glucose, insulin and triglycerides. Participants wore a tri-axial accelerometer whilst in the clinic on both days of the intervention as well as wearing it home on day one. This was used to measure sedentary time and breaks.
Results: After adjusting for age, sex, Body Mass Index (BMI) and activity on day one, on day two, changes in vector magnitude counts, number of breaks and time in breaks from sedentary behaviour were not associated with plasma glucose, plasma insulin and plasma triglyceride AUC and iAUC.
Conclusion: During two days of predominantly prolonged sitting, no significant associations were found between accelerometer measured movement and postprandial glucose, insulin and triglyceride responses.
