How does your circadian rhythm affect nearly every aspect of your health?

The answer

The circadian rhythm is governed by a master clock - the suprachiasmatic nucleus (SCN) - containing roughly 20,000 neurons that synchronize to light via melanopsin receptors in the retinas. The 2017 Nobel Prize in Physiology or Medicine was awarded to Jeffrey Hall, Michael Rosbash, and Michael Young for discovering the molecular mechanisms of circadian clocks involving Period and Timeless genes. Disrupted circadian rhythms measurably increase disease risk: night shift workers have 17-24% higher breast cancer rates, and a 2023 study found that eating outside circadian windows increases type 2 diabetes risk by 59%. Even a one-hour shift during daylight saving time increases heart attacks by 24% on the following Monday. Every organ has local clock genes coordinating metabolism, hormone release, and cell repair.