Zeitgeber = Your Body's Timekeeper
Zeitgebers are cues given by the environment that reset the circadian rhythm.
Zeitgebers are environmental cues like sunlight, exercise, and eating that impact your circadian rhythm and energy levels throughout the day. Temperature and the even social interactions can also create environmental cues that tell your body when to be alert. These external cues reset the internal body clock, also known as your circadian rhythm. Naturally occurring sunlight is the strongest zeitgeber because of its impact on hormones like melatonin. Even when our eyes are closed, photoreceptors in the eye can detect sunlight. These photoreceptors respond to sunlight by inhibiting melatonin. Due to the fact that we have become indoor creatures, people are often out of touch with their circadian rhythm. This happens when you do not entrench your zeitgebers within your daily schedule.