Biological clock and hormone levels affected by winter time transition

The transition to winter time, scheduled for the night of October 24 to 25, affects the human biological clock and hormonal balance. According to Professor Alfredo Pontecorvi of Policlinico Gemelli in Rome, the shift requires the body to resynchronize its internal rhythms.

Key physiological impacts include fluctuations in hormones with precise circadian rhythms, such as cortisol and growth hormone. While short-term effects like sleepiness, fatigue, irritability, and headaches are common during the adaptation period, experts suggest long-term issues are unlikely. Some studies have noted potential increases in cardiovascular and cerebrovascular incidents around time changes, though more research is needed to confirm this.

Research published in Chronobiology International highlights that light is the primary regulator for cortisol levels. An Australian study found that for every hour the sunrise is delayed, median cortisol levels increased by 4.8%, indicating that the body relies heavily on natural light rather than artificial time changes to regulate its rhythm.