This study evaluates the effect of bright light on postprandial blood glucose metabolism in obese subjects with impaired fasting glucose and/or impaired glucose tolerance.
Light has a major influence on the biological clock and several studies suggest that bright light during the day and dim light in the evening are beneficial for the circadian timing system. Nowadays, large parts of the population spend 90% of their time indoors and are thereby exposed to artificial lighting instead of daylight. The artificial light levels are relatively low during the day and continue relatively late in the evening. The lack of a clear natural light-dark cycle could results in delayed timing of the biological clock relative to the behaviour. Optimizing the lighting conditions under controlled laboratory settings might lead to better alignment of the biological clock, which in turn could improve metabolic parameters such as glucose control.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
14
Participants will be exposed to bright light (1250 lux) between 8:00 and 18:00 and to dim light (5 lux) between 18:00 and 23:00.
Participants will be exposed to dim light (10 lux) between 8:00 and 18:00 and to dim light (1250 lux) between 18:00 and 23:00.
Maastricht University
Maastricht, Limburg, Netherlands
Postprandial glucose (mg/dL)
Assessed with a continuous glucose monitor (CGM)
Time frame: Study Day 1-3
Glucose levels (mmol/L) in the postprandial state
venous blood draw every 30 min for 4 hours after breakfast and after dinner
Time frame: Study Day 2-3
Free fatty acid levels (µmol/L) in the postprandial state
venous blood draw every 30 min for 4 hours after breakfast and after dinner
Time frame: Study Day 2-3
Triglycerides levels (mmol/L) in the postprandial state
venous blood draw every 30 min for 4 hours after breakfast and after dinner
Time frame: Study Day 2-3
Insulin levels (µU/mL) in the postprandial state
venous blood draw every 30 min for 4 hours after breakfast and after dinner
Time frame: Study Day 2-3
Continuous interstitial glucose (mg/dL)
Assessed with continuous glucose monitor (CGM)
Time frame: Study Day 1-3
Energy expenditure
continuous measurement with whole room indirect calorimetry
Time frame: Study Day 1-3
Core body temperature (CBT) and skin temperature
Measured with a telemetric pill (CBT) and 14 temperature sensors (iButtons) in degrees celsius
Time frame: Study Day 1-3
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