Anyone who has suffered from jet lag or struggled after turning the clock forward or back an hour for daylight saving time knows all about what researchers call your biological clock, or circadian rhythm – the “master pacemaker” that synchronizes how your body responds to the passing of one day to the next.
This “clock” is made up of about 20,000 neurons in the hypothalamus, the area near the center of the brain that coordinates your body’s unconscious functions, like breathing and blood pressure. Humans aren’t the only beings that have an internal clock system: All vertebrates – or mammals, birds, reptiles, amphibians, and fish – have biological clocks, as do plants, fungi, and bacteria. Biological clocks are why cats are most active at dawn and dusk, and why flowers bloom at certain times of day.
