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Curr Biol. 2018 Nov 19;28(22):3685-3690.e3. doi: 10.1016/j.cub.2018.10.005. Epub 2018 Nov 8.

Human Resting Energy Expenditure Varies with Circadian Phase.

Author information

1
Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA; Division of Sleep Medicine, Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA.
2
Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA.
3
Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA; Division of Sleep Medicine, Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA; Division of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Boston, MA 02115, USA; Department of Biobehavioral Health, Pennsylvania State University, University Park, PA 16802, USA.
4
Division of Endocrinology, Diabetes, and Hypertension, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA.
5
Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA; Division of Sleep Medicine, Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA. Electronic address: jduffy@research.bwh.harvard.edu.

Abstract

There is emerging evidence that circadian misalignment may alter energy expenditure, leading to obesity risk among those with irregular schedules [1-5]. It has been reported that energy expenditure is affected by the timing of sleep, exercise, and meals [6]. However, it is unclear whether the circadian system also modulates energy expenditure, independent of behavioral state and food intake. Here, we used a forced desynchrony protocol to examine whether fasted resting energy expenditure (REE) varies with circadian phase in seven participants. This protocol allowed us to uncouple sleep-wake and activity-related effects from the endogenous circadian rhythm, demonstrating that REE varies by circadian phase. REE is lowest at circadian phase ∼0°, corresponding to the endogenous core body temperature (CBT) nadir in the late biological night, and highest at circadian phase ∼180° in the biological afternoon and evening. Furthermore, we found that respiratory quotient (RQ), reflecting macronutrient utilization, also varies by circadian phase. RQ is lowest at circadian phase ∼240° and highest at circadian phase ∼60°, which corresponds to biological morning. This is the first characterization of a circadian profile in fasted resting energy expenditure and fasted respiratory quotient (with rhythmic profiles in both carbohydrate and lipid oxidation), decoupled from effects of activity, sleep-wake cycle, and diet in humans. The rhythm in energy expenditure and macronutrient metabolism may contribute to greater weight gain in shift workers and others with irregular schedules.

KEYWORDS:

carbohydrate oxidation; circadian phase; circadian rhythm; lipid oxidation; metabolic rate; respiratory quotient; resting energy expenditure

PMID:
30416064
DOI:
10.1016/j.cub.2018.10.005

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