Nuthetal

Researchers are investigating how short-term full-body cold-water immersion affects decision-making, psychological well-being, and body functions compared to warm-water immersion. This behavioral study uses a randomized within-subject cross-over design and focuses on healthy adults aged 18 to 40 years. The aim is to better understand the effects of cold exposure on value-based choices and related physiological and psychological responses. Participants will attend two visits approximately 30 days apart. During each visit, they will undergo a 10-minute full-body head-out immersion in either cold water 10-16C or warm water 30-36C. The study measures responses before and after immersion, including heart and respiratory activity, skin conductance, pupil size, body temperature, blood samples, and various decision-making and psychological tasks. Each session includes resting and task-based evaluations to compare the effects of cold versus warm water. Throughout the study, participants will complete questionnaires on emotions, stress, self-efficacy, and well-being. Researchers will perform non-invasive recordings and collect blood samples at four time points during visits. The primary outcomes include risk-taking behavior, heart rate variability, skin conductance, and blood markers, all assessed on both visits. This comprehensive monitoring aims to capture changes in physiology, behavior, and psychological states linked to cold-water exposure.

Researchers are studying how the expectation of food availability affects eating behavior, mood, body awareness, and food consumption in healthy women with natural menstrual cycles. This randomized crossover study focuses on understanding how knowing or not knowing meal timing influences decisions, hormone levels, and stress. Participants attend two afternoon sessions after fasting overnight. In one session, meal timing and duration are clearly shared certain condition, while in the other, this information is withheld uncertain condition. Each visit includes cognitive and behavioral tests followed by a buffet meal where women can eat freely. Blood samples are taken at six specific times to measure hormones like ghrelin, leptin, insulin, glucose, and cortisol. Additionally, participants track their food intake using a smartphone app for three days before the first visit. During the study visits, researchers measure food intake, decision-making skills, mood, stress, body signals, and hormone fluctuations. They also assess heart rate, skin responses, and self-reported hunger, fullness, and cravings. The study monitors behavioral and metabolic responses about 30 days apart, gathering detailed data on eating patterns and emotional states. This comprehensive monitoring helps explore how perceived meal certainty impacts various physical and psychological factors.

Researchers are investigating how restricting eating times combined with moderate calorie reduction affects blood sugar control and heart health in people who are overweight or obese, including those with normal glucose levels, prediabetes, or type 2 diabetes. The study aims to understand differences between eating mainly in the morning versus mainly in the evening and explores the biological mechanisms behind these effects. This trial is conducted by the German Institute of Human Nutrition using a crossover design. Participants will follow two different 8-hour eating windows one mainly in the morning early time-restricted eating and one mainly in the evening late time-restricted eating. Each eating phase lasts five weeks, separated by a 10 to 12-week break. During each phase, participants reduce their daily calorie intake by 25% and replace one meal with a calorie-reduced product. The timing of meals is adjusted according to each persons natural daily rhythms chronotype. During the study, participants will undergo various assessments including continuous glucose monitoring to track 24-hour blood sugar levels, measurements of insulin, glucagon, cholesterol, body weight, body composition, blood pressure, and inflammation markers. Researchers will also study gene expression, microbiome changes, sleep patterns, and quality of life. The total study duration includes two five-week intervention periods plus a washout phase, with detailed monitoring throughout to evaluate the impact of meal timing on metabolic health.