Intermittent Fasting, Insufficient Sleep, and Circadian Rhythm: Interaction and Effects on the Cardiometabolic System

Abstract

Sleep, circadian rhythms, and fasting/feeding are important factors that affect cardiometabolic function. Here, we review recent studies that assessed the role of intermittent fasting, short sleep duration, and circadian rhythm disruption, as well as their interactions, on the risk of cardiometabolic dysfunction. The cardiometabolic system is sensitive to sleep, circadian rhythms, and fasting/feeding patterns. Recent data show that these factors may influence each other and hence, directly or indirectly affect cardiometabolic risk. Fasting/feeding schedules and mealtimes may cause misalignment of the circadian system resulting in several cardiometabolic disturbances. Recent data reveal that intermittent fasting (IF) improves several cardiometabolic indicators in both laboratory animals and humans maintained on IF diets during alternate day fasting, diurnal IF, or time-restricted feeding. However, most of the human studies recruited a modest number of participants and did not control for several confounding factors that may have affected the measurement of cardiometabolic parameters, such as sleep duration and timing, energy expenditure, and light exposure. Current evidence shows that IF, sleep, and circadian rhythms can affect cardiometabolic risk both individually or collectively. IF, adequate sleep, and matching mealtimes with the circadian clock improve several cardiometabolic parameters. More extensive human studies that assess the interaction between the three factors in the general population are needed to complement the currently available short-term laboratory-based human studies.