The nutritional and metabolic impact of night shift work in a real-world setting

Growing evidence from large epidemiological and small lab-controlled studies links night shift work to impaired sleep, cognitive performance, and cardiometabolic health, but evidence from real-world occupational environments remains limited. Using multiple wearable devices and mobile health apps, alongside other objective and subjective assessment tools, we assess the nutritional intake and cardiometabolic parameters among shift workers during three consecutive night shifts and three consecutive day shifts. Here, we report data on 72 night shift workers, consisting of 96% healthcare workers, 82% female, with a median age of 31 years and a median body mass index 22.7 Kg/m2. While intake of calories, protein, and fat is reduced during night shifts, glycemic variability and postprandial glucose spikes are increased compared to day shifts. After three consecutive night shifts, the morning systolic blood pressure is elevated, plasma cortisol is reduced, and the 24-hour heart rate and heart rate variability are altered, indicating disrupted parasympathetic function. Exploratory analysis reveals higher protein intake correlates with lower glycemic variability, whereas nighttime eating is associated with increased glycemic variability. Future interventional studies could target meal composition and meal timing to improve glycemic variability in night shift workers.