Circadian Misalignment

This study plans to learn more about whether exercise can help protect the body from health problems that happen when a person's sleep and daily schedule are out of sync with their natural body clock (circadian rhythm).

This study evaluates the effects of a Combined Lifestyle Intervention Program (CLIP) on sleep, lifestyle behaviors, obesity risk and health in night-shift workers. The primary objective is to assess the effect of the CLIP on objectively measured sleep duration. Secondary objectives include behavioral outcomes related to sleep, diet, physical activity, and stress, as well as body weight and metabolic outcomes, . It is hypothesized that CLIP participants will show a greater increase in sleep duration than controls, alongside favorable changes in lifestyle and health outcomes.

The purpose of this study is to examine the impact of timed cortisol release or differently timed cortisol rhythms on insulin resistance in both men and women undergoing sleep restriction. Chronic sleep loss is highly prevalent, affecting 1 in 3 adults in the US. Chronic sleep loss causes stress which induces insulin resistance and leads to obesity and type 2 diabetes. Many factors contribute to sleep loss including shift work, environmental disturbances, sleep/circadian disorders and comorbid medical and mental health conditions. Sleep loss increases the stress hormone cortisol in the evening and decreases daytime testosterone. Examining these hormones in a controlled laboratory environment under different sleep schedules may help researchers find solutions for adults experiencing negative health consequences related to chronic sleep loss.

This study will test whether biological sex influences how the body responds to circadian misalignment-a mismatch between the internal body clock and the timing of sleep and eating (as can occur with shift work or jet lag). Researchers will examine how circadian misalignment affects appetite regulation (hunger/fullness) and glucose metabolism (blood sugar control), and whether these effects differ between females and males. Findings may help inform more personalized shift work schedules and targeted strategies to reduce metabolic health risks and sex-related differences in clinical care.

Sleep is an important factor for overall health. This study will see how different light exposure patterns and food intake impact a person's metabolism (how the body breaks down food) when sleeping is reduced. Participants will attend 6 to 8 in-person visits to the study clinic, including three overnight stays. People will complete surveys and medical tests. The study will last about 4 to 6 months.