Chronic Insufficient Sleep Has a Limited Impact on Circadian Rhythmicity of Subjective Hunger and Awakening Fasted Metabolic Hormones

Abstract

Weight gain and obesity have reached epidemic proportions in modern society. Insufficient sleep—which is also prevalent in modern society—and eating at inappropriate circadian times have been identified as risk factors for weight gain, yet the impact of chronic insufficient sleep on the circadian timing of subjective hunger and physiologic metabolic outcomes are not well understood. We investigated how chronic insufficient sleep impacts the circadian timing of subjective hunger and fasting metabolic hormones in a 32-day in-laboratory randomized single-blind control study, with healthy younger participants (range, 20–34 years) randomized to either Control (1:2 sleep:wake ratio, 6.67 h sleep:13.33 h wake, n = 7, equivalent to 8 h of sleep per 24 h) or chronic sleep restriction (CSR, 1:3.3 sleep:wake ratio, 4.67 h sleep:15.33 h wake, n = 8, equivalent to 5.6 h of sleep per 24 h) conditions. Participants lived on a “20 h day” designed to distribute all behaviors and food intake equally across all phases of the circadian cycle over every six consecutive 20 h protocol days. During each 20 h day, participants were provided a nutritionist-designed, isocaloric diet consisting of 45–50% carbohydrate, 30–35% fat, and 15–20% protein adjusted for sex, weight, and age. Subjective non-numeric ratings of hunger were recorded before and after meals and fasting blood samples were taken within 5 min of awakening. Subjective levels of hunger and fasting concentrations of leptin, ghrelin, insulin, glucose, adiponectin, and cortisol all demonstrated circadian patterns; there were no differences, however, between CSR and Control conditions in subjective hunger ratings or any fasting hormone concentrations. These findings suggest that chronic insufficient sleep may have a limited role in altering the robust circadian profile of subjective hunger and fasted metabolic hormones.Clinical Trial RegistrationThe study was registered as clinical trial #NCT01581125.

Sex differences in the circadian misalignment effects on energy regulation

“…We further found that circulating active ghrelin changed differently under circadian misalignment during wake (increase) versus sleep (decrease) periods. This can be attributed to the endogenous circadian rhythm of active ghrelin, for which the nadir (in the biological day) coincides with the sleep episodes of the circadian misalignment protocol and the peak (in the biological evening/night) coincides with the wake periods during circadian misalignment (33,34). Moreover, we found that the change in active ghrelin during misaligned wake periods was modulated by sex, with females as the major contributors to the overall increase.…”

Timing of Food Intake: Identifying Contributing Factors to Design Effective Interventions

“…A circadian rhythm was observed for hunger, whereby a trough in hunger was observed during the biological morning (0800) and a peak during the biological evening (2000). These hunger rhythms are stable and remained the same even upon changing meal timing (16) and under conditions of chronic insufficient sleep (86). These rhythms in hunger and appetite relate to the rhythms of the appetite hormone ghrelin.…”

“…These rhythms in hunger and appetite relate to the rhythms of the appetite hormone ghrelin. Acylated ghrelin (the active form) has higher concentrations in the biological evening than in the biological morning, both in the fasted and postprandial states, consistent with hunger (86,87). The hunger peak at 2000 also coincides with the average timing of the last eating episodes in the United States at 2018, and the hunger trough at 0800 may also partly explain variability in breakfast preference (47).…”

Acute Sleep Curtailment Increases Sweet Taste Preference, Appetite and Food Intake in Healthy Young Adults: A Randomized Crossover Trial

“…The effects of sleep curtailment with a long period or advanced wake time would be expected to differ from acute effects of sleep curtailment with delayed bed time. Previous study has reported that chronic sleep restriction does not alter subjective hunger levels and appetite hormones, but rather, they are more circadian-rhythm-dependent [30]. Olfactory responses seem to change based on circadian timing [31], which could also impact taste response.…”