Sleeping during the day: effects on the 24-h patterns of IGF-binding protein 1, insulin, glucose, cortisol, and growth hormone

Abstract

Background: Disturbed sleep is a major risk factor for metabolic disturbances, including type 2 diabetes, but the involved mechanisms are still poorly understood. We investigated how an acute shift of sleep to the daytime affected IGF-binding protein 1 (IGFBP1), which is a risk factor for diabetes. Methods: Seven healthy men (age, 22-32 years) participated in a night sleep condition (sleep 2300-0700 h) and a day sleep condition (0700-1500 h) with hourly blood samples taken for 25 h (starting at 1900 h) and isocaloric meals every 4th hour awake. The blood samples were analyzed for IGFBP1, insulin, GH, glucose, and cortisol. Result: The acute shift of sleep and meal timing (to 8 h) shifted the 24-h patterns of IGFBP1, glucose, insulin, and GH to a similar degree. However, the day sleep condition also resulted in elevated levels of IGFBP1 (area under curve (AUC)C22%, P!0.05), and reduced glucose levels (AUCK7%, P!0.05) compared with nocturnal sleep. Sleeping during the day resulted in elevated cortisol levels during early sleep and reduced levels in late sleep, but also in increased levels the subsequent evening (P's!0.05). Conclusion: Sleep-fasting seems to be the primary cause for the elevation of IGFBP1, irrespective of sleep timing. However, sleeping during the day resulted in higher levels of IGFBP1 than nocturnal sleep, suggesting altered metabolism among healthy individuals, which may have implications for other groups with altered sleep/eating habits such as shift workers. Moreover, sleep and meal times should be accounted for while interpreting IGFBP1 samples.

Examining multiple sleep behaviors and diurnal salivary cortisol and alpha-amylase: Within- and between-person associations

“…Shortened sleep or high levels of sleep duration variability may be acting as a stressor influencing cortisol output or may be representative of higher levels of stress influencing sleep behavior. This is consistent with prior studies that have demonstrated changes to 24-h patterns of cortisol in shift workers who naturally vary sleep schedules and sleep durations, as well as with studies that have experimentally manipulated sleep schedules (Rehman et al, 2010). …”

Impact of circadian misalignment on energy metabolism during simulated nightshift work

“…Possible contributing mechanisms for decreased EE at the beginning of the daytime sleep opportunity include reduced resting metabolic rate (31) and sleep-induced decreases in the metabolic hormones cortisol, norepinephrine, and epinephrine that typically increase EE (32,33) and are highest at this circadian time (5). During sleep, circulating cortisol, norepinephrine, and epinephrine levels are reduced and morning sleep after the nightshift could decrease these hormones (34,35), leading to decreased EE. Our finding of shorter REM latencies during daytime sleep may be associated with reduced catecholamine levels, thereby potentially decreasing EE (34).…”

U-shaped relationships between sleep duration and metabolic syndrome and metabolic syndrome components in males: a prospective cohort study

“…Frequent napping and long nap duration were shown to increase the risk of type 2 diabetes mellitus [17,18]. In in vitro experiments, sleeping during the daytime resulted in higher levels of insulin-like growth factor binding protein 1 (IGFBP1) than nocturnal sleep [19]. In addition, cell and molecular links exist between disorders of circadian rhythms and sleep with MS [20].…”