You thought an extra hour of sleep was salvation? Here's what moving the clock actually does to the body!

Croatia will switch back to winter time on Sunday, October 25, 2026, moving clocks from three to two in the morning. While this shift grants residents an extra hour of sleep, medical experts warn that the change can disrupt physical and mental health routines. The practice aligns Croatia with most European countries, continuing a semi-annual adjustment despite previous proposals by the European Commission to abolish it. Member states have yet to reach a final agreement on ending the seasonal switch, so the traditional rhythm persists for now. The primary biological impact stems from the disruption of the circadian rhythm, the body’s internal 24-hour clock. This cycle regulates vital functions including hormone secretion, body temperature, appetite, and sleep-wake cycles. Even a one-hour shift can temporarily disturb these processes. Many individuals report feeling tired, sleepy, or having difficulty concentrating in the days following the change. Doctors advise gradual adaptation starting one week before the switch to mitigate these effects. Beyond immediate fatigue, the earlier onset of darkness poses specific challenges. Reduced daylight exposure during autumn and winter months is linked to lower mood and energy levels. A Danish study involving more than 180,000 cases found that diagnoses of depression were approximately eight percent higher than expected after the autumn clock change. Researchers attributed this increase to the transition to winter time, noting that the earlier sunset plays a significant role. Lack of sunlight is also associated with seasonal affective disorder, a form of depression that typically occurs during fall and winter months. However, recent data suggests the autumn shift has some positive health outcomes. A large 2025 British study covering nearly 700,000 patients observed a decrease in certain health complaints in the week following the switch to winter time. Cases of acute cardiovascular diseases dropped by two percent, anxiety cases fell by three percent, and insomnia problems decreased by eight percent. Researchers hypothesize that the additional hour of sleep may benefit physiological processes such as blood pressure regulation and inflammation control. They caution that these findings represent correlations recorded in the research rather than direct proof that the clock change itself improves health. The relationship between clock changes and heart health has been debated for years. Previous studies often linked the spring forward shift, which results in lost sleep, to increased rates of heart attacks, traffic accidents, and sleep disorders. Some earlier research suggested similar risks existed around both seasonal transitions. However, a new American study analyzing ten years of patient data found no significant rise in heart attacks during periods surrounding either the spring or autumn shifts. The lead author described this as the most extensive review of the link between clock changes and cardiac health to date. Scientists noted that other seasonal factors, such as the spread of respiratory infections and flu viruses, likely influence heart health more significantly than the time change itself. Chronic lack of sleep remains a critical risk factor for the cardiovascular system, independent of the clock adjustment. Sleep medicine professionals generally advocate for abolishing seasonal time changes entirely. The American Academy of Sleep Medicine supports moving permanently to standard, or winter, time. This approach would better align human schedules with natural biological rhythms. Morning light helps wake the body and synchronize the internal clock, while excessive evening light can delay the release of melatonin, the hormone responsible for regulating sleep. Consequently, doctors specializing in sleep medicine believe permanent standard time could be healthier than constant daylight saving time. Adjustment to the new schedule usually takes just a few days for most people, though those with existing sleep issues may find it more difficult. Experts recommend maintaining consistent bedtimes and wake times daily. Exposure to daylight, particularly in the morning, is advised to help reset the circadian rhythm. As the days grow shorter and darker, balancing sleep hygiene with adequate light exposure becomes essential for managing the physical and psychological impacts of the seasonal transition.