Circadian Rhythm 101: How To Support Your Body's Internal Clock Every Day

Your internal clock, also known as your circadian rhythm, enables your body to automatically know when to wake up and get out of bed and when it’s time to go to sleep, eat, and even ovulate. It also plays a major role in how productive and focused1 you are.

The circadian rhythm is the biological mechanism that controls the sleep-wake cycle, when hormones are released for ovulation and digestion, and when it is time for your body to sleep so that your muscles can rest, your memories can consolidate, and your immune system can recover. Just like the ebbs and flows of nature, your body runs on a cyclical rhythm thanks to this internal clock.

This crucial process is kicked off by the natural light that comes from the sun’s rays that is picked up by the suprachiasmatic nucleus2 (SCN) in your brain.

When sunlight comes in through the eyes, the SCN picks up the cue that it's daylight and time to get up and be active. As the light diminishes and then disappears, the clock signals the body that it is time to sleep.

In short: absolutely. It's pretty cool that we have a clock that is able to adjust our biological rhythm to our environment, but it's not so cool that our clocks are actually fairly screwed up because we don't abide by nature’s rhythms.

We mess up our clock by staying up late, working on our computers or smartphones, rarely getting outdoors or exercising, eating processed foods, going on drinking or food binges in the late-night hours, and drinking large volumes of caffeine to stay awake—just to name a few.

Though it can be helpful to use a warm, sun-mimicking lamp when necessary, it's also important to expose yourself to natural light throughout the day. Spend more time outdoors where you can, and consider taking longer trips in nature for the sake of your health.

To give the body proper time to unwind, try to limit the number of stressful activities you do before bed (particularly ones that are on the computer!). Instead, use the hour before sleep to read, journal, or do a calming meditation. Cut back on caffeine—particularly in the evenings—and sip one of these calming teas at night instead.

Harvard scientists have discovered that we have a food-related clock that might supersede the light-based master clock. It was likely designed evolutionarily to avoid starvation.

Their studies suggest that fasting can help readjust sleep clocks in people with jet lag, so you can try a 16-hour fast by eating an early dinner around 4 p.m. and not eating again until 8 a.m. the following morning. Then, go back to a normal eating regimen, making sure you have 12 hours in between dinner and breakfast the next day.

Your "clock genes" and the regulation of all biological systems are intricately connected to the stress response. Higher stress levels offset your stress hormones and your melatonin levels, leading to more dysfunction of your internal clock.