What is a circadian rhythm, and why does it matter?Updated 2 months ago

Your circadian rhythm, often called your sleep/wake cycle, is your body’s internal 24-hour clock. It helps regulate when you feel awake and alert, when you get sleepy, and how your body carries out essential daily functions.

This rhythm is guided by a “master clock” in your brain that coordinates smaller clocks throughout your body. Together, they help manage things like sleep timing, digestion, hormone release, body temperature, and energy levels.

The master clock is located in a part of the brain called the suprachiasmatic nucleus (SCN). One of the most important signals it responds to is light. Your eyes send light information directly to the SCN, helping your brain understand whether it’s day or night. This light sensitivity is a natural process shared by nearly all living organisms. (Source: NCBI)

Based on the light it detects, the SCN sends signals throughout your body to adjust your internal rhythms. When this system is working well, your body stays in sync and functions smoothly.

When your circadian rhythm is disrupted, often due to artificial lighting, screens, or irregular schedules, it can affect sleep quality, mood, metabolism, and overall health. Supporting your natural light/dark cycle is one of the most important steps you can take toward better sleep, energy, and wellbeing.