Josephine Arendt

Josephine Arendt (née Wragg) (1941–2023) was a British biologist who served as Professor of Chronobiology at the University of Surrey. She established the Centre for Chronobiology at the University of Surrey. Her research considered circadian rhythms, melatonin and sleep. She was elected Fellow of the Royal College of Pathologists and the Royal Society of Medicine.

Early life and education Arendt was born in Newark-on-Trent. Her father was a prisoner of war in Austria, and the family moved to Guernsey when he returned. Her doctoral research considered the metabolism of 5-hydroxyindole. After graduating, Arendt moved to Queen Charlotte's and Chelsea Hospital and eventually to Geneva, where she worked on Xenopus laevis. She developed immunotechnology to characterise and understand the role of melatonin and its metabolites in sleep and the circadian rhythm. She studied how they respond to light and their responses in conditions such as shift work, polar nights and jet lag. She was one of the first to scientifically describe jet lag,

Arendt created a situation where volunteers were kept in darkened rooms without clocks, light or social cues. Under typical circumstances bodies follow a circadian rhythm, which can be extended from 23 to 25 hours when deprived of context. Her observations helped to explain why humans can accommodate an extra hour of sleep as opposed to losing it. Over the course of a 23-hour sleep cycle, hormones are secreted at the wrong times, causing a person to feel awake and hungry at inappropriate times. Disruptions to circadian rhythms in people who work night shifts or as flight attendants can cause carcinogenic effects.

Awards and honours Fellow of the Royal College of Pathologists Fellow of the Royal Society of Medicine Karolinska Institute Medal of St Goran's Hospital Medal of Justus von Liebig University Ernst and Berta Scharrer Medal European Biological Rhythms Society Johannes Ariens Kappers Meda Medical University of Łódź Doctor Honoris Causa

Selected publications