How the Transition to Standard Time Affects Human Circadian Rhythms
Prof. Yaron Dagan explains how the transition to standard time affects human biological rhythms, circadian cycles, and melatonin production in the brain.
The transition from daylight saving time to standard time impacts human biological rhythms, primarily driven by light and darkness, according to Prof. Yaron Dagan, head of the sleep medicine division at Assuta and Maccabi Healthcare Services.
Speaking to the press, Prof. Dagan explained that human circadian rhythms naturally span slightly longer than 24 hours—roughly 25 or 26 hours—and require environmental cues like light and darkness to synchronize with a 24-hour day.
Specialized photoreceptors in the eyes, which are not involved in vision, signal light and darkness levels to the brain's pineal gland. This gland secretes melatonin, often called the hormone of darkness, which regulates alertness and sleepiness.
Comparing these biological mechanisms to extreme environments, researchers note that prolonged darkness in polar regions can trigger seasonal affective disorder, leading to higher rates of depression in northern countries compared to other regions.
