Research has shown that replacing sitting time with low intensity physical activity (such as slowly walking and standing) has beneficial effects on metabolic health, like insulin sensitivity, comparable to improvements after sitting all day in combination with 1h streneous exercise.

The main objective of this study is to investigate the underlying mechanisms responsible for improved insulin sensitivity after 4 days of sitting less compared to sitting and exercise in healthy obese women. Our secondary objective is to investigate the effects of sitting less on cardio metabolic parameters.

Inclusion Criteria:

• Signed informed consent
• Caucasian
• Postmenopausal women
• Aged 45-70 years at start of the study
• Body mass index (BMI) 25 - 35 kg/m2
• Stable dietary habits (no weight loss or gain >5kg in the past 3 months)
• Sedentary lifestyle (not more than 2,5 hours of exercise per week in the past 3 months)

Exclusion Criteria:

• Not able to complete the sitless try-out day according to the protocol
• Active diseases (cardiovascular, diabetes, liver, kidney, cancer or other)
• No use of medication interfering with investigated study parameters (as determined by responsible physician)
• Alcohol consumption of >2 servings per day
• Smoking in the past 6 months
• Participation in another biomedical trial which may have an effect on insulin sensitivity less than one month before the start of the study (screening visit)
• Mental or physical disability which interferes with physical activity
• Subjects with contra-indications for magnetic resonance imaging (MRI)
• Reported participation in night shift work 2 weeks prior to the start of the study (screening visit) and during study participation. Night work is defined as working between midnight and 6.00 AM.