Background of the study:

A sedentary lifestyle and obesity are well known risk factors of type 2 diabetes. The major focus of current guidelines for type 2 diabetes prevention is on energy balance. Physical activity guidelines recommend at least 30 minutes/day of moderate to vigorous physical activity (MVPA). However, no advice is given how the other 23.5 hours of the day should be spent. Several recent epidemiologic studies suggest that excessive sitting, independent of moderate to vigorous physical activity, has detrimental health effects. Another possibility to sit less is by increasing low intensity physical activities as slowly walking and standing. A recent published study of Duvivier and colleagues suggests that sitting less and replacing it by slowly walking and standing has a better effect on insulin action and cardiovascular risk factors than the combination of one hour MVPA per day and sitting the rest of the day in healthy subjects (Duvivier et al. PLOS ONE 2013). Until now this research is not performed in subjects with overweight/obesity.

Objective of the study:

To assess the effect of low intensity physical activity on plasma insulin levels, cognition and mood in subjects with overweight/obesity

Study population:

21 subjects between 40-80 years old with overweight/obesity

Intervention:

2 activity regimes of 4 days: a sitting regime and a "sit less" regime

Inclusion Criteria:

• Signed informed consent
• Men and postmenopausal women: 40-80 years old
• BMI: 25.0 - 35.0 kg/m2
• Maximum 2.5 hours of MVPA per week (during last 3 months)
• Having a general practitioner
• Agreeing to be informed about medically relevant personal test-results by a physician
• Accessible veins on arms as determined by examination at screening

Exclusion Criteria:

• Reported participation in another biomedical trial which may have an effect on insulin sensitivity one month before the pre-study examination or during the study
• Blood donation in the past three months
• Reported participation in night shift work 2 weeks prior to pre-study investigation or during the study. Night work is defined as working between midnight and 6.00 AM.
• Consumption of >14 (women) or > 21 (men) alcoholic units per week
• Reported dietary habits: medically prescribed diet, slimming diet;
• Reported weight loss (>2kg) in the last three months prior to the screening;
• Not being able to execute at least three (out of four) cognition tests in the training session
• Not being able to execute the sit less try-out day
• Being an employee of Unilever or the collaborating research departments in Maastricht University Medical Centre
• Experimental drug use (during the last 3 months)
• Use of insulin, oral blood glucose lowering medication (metformin and/or SU-derivatives and/or DPP-IV inhibitors), corticosteroids or vitamin K antagonists in the last 3 months
• Fasting plasma glucose level > 6.9 mmol/L
• Medical conditions which make participation in the study not responsible which will be decided by a medical doctor during screening
• Other clinically relevant abnormalities in clinical chemistry at screening (to be judged by a medical doctor)
• Mental or physical disability which interferes with physical activity