Metabolic Effects of Natural Office Light in Type 2 Diabetes
Condition: Diabetes Mellitus, Type 2; Circadian Dysregulation
MeSH terms: Chronobiology Disorders; Diabetes Mellitus; Diabetes Mellitus, Type 2
Study type: Interventional

Summary: 
      This study will investigate the potential benefit of scheduled natural daylight exposure to
      improve glucose control in type 2 diabetes (T2D) patients and to unravel molecular mechanisms
      underlying the effects of natural daylight on circadian clocks and (glucose) metabolism in
      human skeletal muscle from T2D patients. Participants will stay at our research facilities
      and will be exposed to natural daylight or artificial light during the daytime over 4.5 days
      in a randomized cross-over design. For both conditions, the evening and night will be spent
      under standardized dim and dark conditions.
    

Detailed description: 
      Obesity and type 2 diabetes (T2D) are both strongly associated with a westernized lifestyle
      of low physical activity levels and high caloric intake. However, recently it has been
      recognized that also our 24-hour culture, characterized by working and eating late, reduced
      sleep (quantity and quality), and excessive light exposure in the evening and at night,
      should be considered as lifestyle factors that may negatively impact metabolic health. In
      this context, a factor that is often overlooked and underestimated is the lack of natural
      daylight since most people spend almost their entire work time in indoor office environments
      with limited access to natural daylight through windows.

      Therefore, this study investigates the potential benefit of scheduled natural daylight
      exposure to improve glucose control in T2D individuals and to unravel molecular mechanisms
      underlying effects of natural daylight on circadian clocks and (glucose) metabolism in human
      skeletal muscle from T2D patients. For this purpose, overweight to obese T2D patients (male
      and female) will undergo a randomized cross-over trial in which each subject serves as its
      own control. Participants will stay at our research facilities and will be exposed to natural
      daylight or artificial light during the daytime over 4.5 days. For both conditions, the
      evening and night will be spent under standardized dim and dark conditions, respectively.
      Over these two 4.5 days intervention periods, extensive 24h metabolic profiling will be
      conducted, including 24h continuous glucose monitoring, 24h blood and saliva sampling, 24h
      blood pressure and heart rate assessments, 24h core and skin temperature assessments, 24h
      energy expenditure and whole-body substrate metabolism, and a skeletal muscle biopsy and a
      mixed meal tolerance test with indirect calorimetry will be performed on the respectively
      last test day.
    

Intervention name(s): Natural or artificial office light exposure
Intervention type(s): Other
Intervention description(s): Over 4.5 days, participants will stay at our research facilities under different light conditions. Over these days different measurements will take place, including 24h continuous glucose monitoring, 24h blood and saliva sampling, 24h blood pressure and heart rate assessments, 24h core and skin temperature assessments, 24h energy expenditure and whole-body substrate metabolism, and a skeletal muscle biopsy and a mixed meal tolerance test with indirect calorimetry will be performed on the respectively last test day.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: circadian rhythm