Day-Night Rhythm in Human Skeletal Muscle

Day-night Rhythm in Human Skeletal Muscle Metabolism

This study evaluates the existence of a day-night rhythm in skeletal muscle energy metabolism in healthy lean subjects. Subjects will stay at the research facility for 44 hours with a standardized living protocol during which several measurements of skeletal muscle and whole body energy metabolism will be performed.

Recent evidence from both observational and experimental studies indicates that disobeying our normal day-night rhythm negatively influences our metabolic and cardiovascular health, possibly leading to obesity and type 2 diabetes mellitus (T2DM). An important hallmark of obesity and T2DM is a decreased skeletal muscle mitochondrial function. Interestingly, recent research indicates that also skeletal muscle mitochondrial function under the influence of a day-night rhythm. The main objective of this study is to investigate the presence of a day-night rhythm in skeletal muscle energy metabolism (in particular mitochondrial function) of healthy young participants. Therefore, subjects will stay at the research unit for 44 hours, with standardized meals and sleeping time. During this period we will take five muscle biopsies, perform indirect calorimetry measurements and blood draws.

Inclusion Criteria:

• Caucasian
• Healthy (as determined by dependent physician based on medical questionnaire)
• Male
• Age: 18-35 years
• Normal BMI (18-25 kg/m2)
• Regular sleeping time (normally 7-9h daily)

Exclusion Criteria:

• Extreme early bird or extreme night person (score ≤30 or ≥70 on MEQ-SA questionnaire)
• Heavily varying sleep-wake rhythm
• Shiftwork during last 3 months
• Travel across >1 time zone in the last 3 months
• Engagement in exercise > 2 hours total per week
• Using >400mg caffeine daily
• Smoking
• Unstable body weight (weight gain or loss > 3kg in the last 3 months)
• Significant food allergies/intolerance (seriously hampering study meals)
• Participation in another biomedical study within 1 month before the first study visit
• Any contra-indication to Magnetic Resonance Imaging (MRI) scanning