How disrupted body clocks affect energy use during simulated night shift work

Total daily energy expenditure decreased by ∼3% on each of the second and third nightshift days.

• Energy expenditure increased by ∼4% on the transition day to the first nightshift, following an afternoon nap.
• Energy expenditure decreased by ∼12-16% during scheduled daytime sleep opportunities, despite poor sleep quality.
• Total daily fat utilization increased on the first and second nightshift days, while carbohydrate and protein utilization decreased on the second nightshift day.
• Ratings of hunger were lower during nightshift days, even with decreased levels of the satiety hormones leptin and peptide-YY.
• Findings indicate that working and eating during the biological night may be linked to reduced energy expenditure and increased risk of weight gain.

Simplified