King Grub
2012-08-22, 16:43
Background:
The disruption of the circadian system has been associated with the development of obesity.
Objective:
We examined the effects of circadian misalignment on sleep, energy expenditure, substrate oxidation, appetite, and related hormones.
Design:
Thirteen subjects [aged 24.3 ± 2.5 (mean ± SD) y; BMI (in kg/m2): 23.6 ± 1.7 (mean ± SD)] completed a randomized crossover study. For each condition, subjects stayed time blinded in the respiration chamber during 3 light-entrained circadian cycles that resulted in a phase advance (3 × 21 h) and a phase delay (3 × 27 h) compared with during a 24-h cycle. Sleep, energy expenditure, substrate oxidation, and appetite were quantified. Blood and saliva samples were taken to determine melatonin, glucose, insulin, ghrelin, leptin, glucagon-like peptide 1 (GLP-1), and cortisol concentrations.
Results:
Circadian misalignment, either phase advanced or phase delayed, did not result in any changes in appetite or energy expenditure, whereas meal-related blood variables (glucose, insulin, ghrelin, leptin, and GLP-1) followed the new meal patterns. However, phase-advanced misalignment caused flattening of the cortisol-secretion pattern (P < 0.001), increased insulin concentrations (P = 0.04), and increased carbohydrate oxidation (P = 0.03) and decreased protein oxidation (P = 0.001). Phase-delayed misalignment increased rapid eye movement sleep (P < 0.001) and the sleeping metabolic rate (P = 0.02), increased glucose (P = 0.02) and decreased GLP-1 (P = 0.02) concentrations, and increased carbohydrate oxidation (P = 0.01) and decreased protein oxidation (P = 0.003).
Conclusions:
The main effect of circadian misalignment, either phase advanced or phase delayed, is a concomitant disturbance of the glucose-insulin metabolism and substrate oxidation, whereas the energy balance or sleep is not largely affected. Chronically eating and sleeping at unusual circadian times may create a health risk through a metabolic disturbance.
Effect of a phase advance and phase delay of the 24-h cycle on energy metabolism, appetite, and related hormones. Am J Clin Nutr August 22, 2012.
http://www.ajcn.org/content/early/2012/08/20/ajcn.112.037192.full.pdf+html
The disruption of the circadian system has been associated with the development of obesity.
Objective:
We examined the effects of circadian misalignment on sleep, energy expenditure, substrate oxidation, appetite, and related hormones.
Design:
Thirteen subjects [aged 24.3 ± 2.5 (mean ± SD) y; BMI (in kg/m2): 23.6 ± 1.7 (mean ± SD)] completed a randomized crossover study. For each condition, subjects stayed time blinded in the respiration chamber during 3 light-entrained circadian cycles that resulted in a phase advance (3 × 21 h) and a phase delay (3 × 27 h) compared with during a 24-h cycle. Sleep, energy expenditure, substrate oxidation, and appetite were quantified. Blood and saliva samples were taken to determine melatonin, glucose, insulin, ghrelin, leptin, glucagon-like peptide 1 (GLP-1), and cortisol concentrations.
Results:
Circadian misalignment, either phase advanced or phase delayed, did not result in any changes in appetite or energy expenditure, whereas meal-related blood variables (glucose, insulin, ghrelin, leptin, and GLP-1) followed the new meal patterns. However, phase-advanced misalignment caused flattening of the cortisol-secretion pattern (P < 0.001), increased insulin concentrations (P = 0.04), and increased carbohydrate oxidation (P = 0.03) and decreased protein oxidation (P = 0.001). Phase-delayed misalignment increased rapid eye movement sleep (P < 0.001) and the sleeping metabolic rate (P = 0.02), increased glucose (P = 0.02) and decreased GLP-1 (P = 0.02) concentrations, and increased carbohydrate oxidation (P = 0.01) and decreased protein oxidation (P = 0.003).
Conclusions:
The main effect of circadian misalignment, either phase advanced or phase delayed, is a concomitant disturbance of the glucose-insulin metabolism and substrate oxidation, whereas the energy balance or sleep is not largely affected. Chronically eating and sleeping at unusual circadian times may create a health risk through a metabolic disturbance.
Effect of a phase advance and phase delay of the 24-h cycle on energy metabolism, appetite, and related hormones. Am J Clin Nutr August 22, 2012.
http://www.ajcn.org/content/early/2012/08/20/ajcn.112.037192.full.pdf+html