Circadian rhythms

Circadian rhythmsClinical medicine can, at countless times, be ranked high among the most rewarding careers.However, in a profession where both internal and external quality standards are outstandingly high, noticing how you start making mistakes and, at the same time, being unable to take appropriate measures to prevent that, holds potential for personal despair. 1 Nevertheless, it is the reality for the majority of shift workers that is approximately 20% of the workforce in developed economies, among them numerous healthcare providers and first responders.To cite just one example, doctors in training are at a significantly higher risk of blood-borne pathogen exposure, like needle stick injuries, when working at nights than working during the days.2 Shift work ensures our societies standard of living, but it invariably meddles with workers' circadian rhythms, causing a spectrum of pathologies from short-term attention deficits to full-blown disorders with long-term consequences on morbidity and mortality.3,4 On-call situations reinforce fatigue due to aborted sleep cycles, and thus affect procedural performance 5 and, ultimately, patient safety.6 However, this not only affects the service quality of patient care, but also other sectors, such as public utilities, security, transport and communication.While the first written accounts of the importance of rhythmic physiologic phenomena date back centuries before the Common Era*, 7 research into (circadian) rhythms, is what ultimately brought the Nobel Prize in Physiology or Medicine in 2017 to Jeffrey C. Hall, Michael Rosbash and Michael W. Young "for their discoveries of molecular mechanisms controlling the circadian rhythm" 8 in fruit flies.Rhythms allow organisms to adjust to cyclic availabilities and, thus, make better use of the natural resources, be it daylight, daytime temperatures, or nutrition.As promised, 9 circadian rhythms in health and disease have been at the focus of a number of excellent articles published in Acta Physiologica this year.During the last years, the term "gut brain axis" has been coined, and in this line, a number of studies unveil interactions between the metabolic and nervous systems.The role of the gut microbiota to maintain homeostasis has recently emerged.Bidirectional interaction between the intestinal bacteria and the host's circadian clock partake in maintaining circadian rhythmicity: While the host organism generates diurnal oscillations in composition and function of the microbiota, signals from the microbiota, in turn, modulate