Overview & Description: Zeitgeber refers to external cues, such as light and temperature, that synchronize the biological clocks (circadian rhythms) of organisms to the Earth’s 24-hour light/dark cycle. In humans, the most crucial zeitgeber is light, which adjusts the master clock in the brain, influencing sleep-wake cycles and hormonal releases.

Implications:

• Sleep and Health: Understanding zeitgebers is crucial in addressing sleep disorders and optimizing health and wellness.
• Shift Work: It impacts strategies for managing shift work and reducing associated health risks.

References:

• Roenneberg, T., & Merrow, M. (2016). The Circadian Clock and Human Health. Current Biology, 26(10), R432–R443.
• Foster, R. G., & Wulff, K. (2005). The Rhythm of Rest and Excess. Nature Reviews Neuroscience, 6(5), 407–414.