The study by Scheer et al. investigates the adverse metabolic and cardiovascular consequences of circadian misalignment, a condition common in shift workers. Ten adults participated in a 10-day laboratory protocol where they ate and slept at all phases of the circadian cycle, achieving a 28-hour "day." The results showed that circadian misalignment systematically decreased leptin levels, increased glucose and mean arterial pressure, and reduced sleep efficiency. Notably, three out of eight subjects exhibited postprandial glucose responses typical of a prediabetic state. These findings highlight the significant health risks associated with circadian misalignment, including obesity, diabetes, and cardiovascular disease, which are often observed in shift workers. The study also demonstrates the independent and interactive effects of the behavioral and circadian cycles on metabolic, autonomic, and endocrine functions, providing insights into the underlying mechanisms.The study by Scheer et al. investigates the adverse metabolic and cardiovascular consequences of circadian misalignment, a condition common in shift workers. Ten adults participated in a 10-day laboratory protocol where they ate and slept at all phases of the circadian cycle, achieving a 28-hour "day." The results showed that circadian misalignment systematically decreased leptin levels, increased glucose and mean arterial pressure, and reduced sleep efficiency. Notably, three out of eight subjects exhibited postprandial glucose responses typical of a prediabetic state. These findings highlight the significant health risks associated with circadian misalignment, including obesity, diabetes, and cardiovascular disease, which are often observed in shift workers. The study also demonstrates the independent and interactive effects of the behavioral and circadian cycles on metabolic, autonomic, and endocrine functions, providing insights into the underlying mechanisms.