Timing Matters: The Interplay between Early Mealtime, Circadian Rhythms, Gene Expression, Circadian Hormones, and Metabolism-A Narrative Review.

Achieving synchronization between the central and peripheral body clocks is essential for ensuring optimal metabolic function. Meal timing is an emerging field of research that investigates the influence of eating patterns on our circadian rhythm, metabolism, and overall health. This narrative review examines the relationship between meal timing, circadian rhythm, clock genes, circadian hormones, and metabolic function. It analyzes the existing literature and experimental data to explore the connection between mealtime, circadian rhythms, and metabolic processes. The available evidence highlights the importance of aligning mealtime with the body's natural rhythms to promote metabolic health and prevent metabolic disorders. Specifically, studies show that consuming meals later in the day is associated with an elevated prevalence of metabolic disorders, while early time-restricted eating, such as having an early breakfast and an earlier dinner, improves levels of glucose in the blood and substrate oxidation. Circadian hormones, including cortisol and melatonin, interact with mealtimes and play vital roles in regulating metabolic processes. Cortisol, aligned with dawn in diurnal mammals, activates energy reserves, stimulates appetite, influences clock gene expression, and synchronizes peripheral clocks. Consuming meals during periods of elevated melatonin levels, specifically during the circadian night, has been correlated with potential implications for glucose tolerance. Understanding the mechanisms of central and peripheral clock synchronization, including genetics, interactions with chronotype, sleep duration, and hormonal changes, provides valuable insights for optimizing dietary strategies and timing. This knowledge contributes to improved overall health and well-being by aligning mealtime with the body's natural circadian rhythm.

Reopening Sleep Medicine Services in the Conundrum of an Ongoing COVID-19 Pandemic: A Global View.

The emergence of COVID-19 brought all healthcare services around the globe to immense strain; hospitals abandoned elective care for acute care. Like all other elective services, sleep medicine services suffered a partial deadlock due to the closing down of the sleep disorders diagnostic and therapeutic services, although clinical consultations and follow-ups, carried on remotely, allowed some mitigation. Since there is dire need to resume the services, we tried to formulate the principles and guidelines to work in this exigent healthcare setting. Principles and guidelines are based on epidemiological and infection control guidelines besides recommendations of various healthcare organizations and sleep societies, after a requisite web search to extract the data.