Breaking Sitting and Metabolic Health in Sedentary Lean Adults

Two trials are included - Prolonged sitting and Breaking sitting.

In the Prolonged sitting trial, after consuming breakfast, participants sat on a chair for 180 min. After 180 min, lunch was provided. After finishing lunch, participants sat on a chair for another 120 min. In the Breaking sitting trial, after consuming breakfast, participants walked 2 min on a treadmill every 20 minutes for the following 180 min. For the remainder of the time participants sat on the chair. After 180 min, lunch was provided. After finishing lunch, participants continued 2 min of walking every 20 min for the following 120 min. Blood samples were collected in a regular pattern throughout the trials. Energy balance (e.g., energy intake and spontaneous physical activity) was assessed using food diary and an accelerometer until midnight in the trial days once participants left laboratory.

Inclusion criteria

• Physical inactive males and females
• Aged between 20 and 45 years
• Lean healthy (waist circumference less than 90 cm for males and 80 cm for females)
• Weight stable for more than 3 months (no change in weight +/- 3%)
• Non-smoker
• Able to walk comfortably on a treadmill

Exclusion criteria

• Personal history of/existing diabetes, cardiovascular disease, metabolic disease or dyslipidaemia
• Waist circumference > 90 cm for male and > 80 cm for female
• Taking medications that may influence lipid or carbohydrate metabolism or immune system function
• Unable to take part in exercise for any reason (e.g., injury or disability) or a positive response to any questions on the Physical Activity Readiness questionnaire (PAR-Q)