What is Circadian Rhythm?
Circadian rhythm is your body’s 24-hour internal clock, which regulates your sleep/wake cycle. Below we’ll explain how it works, what can disrupt it, how to maintain it and the benefits of doing so, plus how to figure out exactly what yours is.
Circadian Rhythm Definition
The word “circadian” is based on the Latin terms for “around” (circa) and “day” (diem), so your “around-the-day” rhythm dictates the cycles your body goes through--most notably when you wake up and fall asleep.
Your circadian clock is controlled by a part of your brain called the hypothalamus that responds to light. As it gets dark, your brain tells your body to begin producing melatonin, which makes you feel tired.
Early Bird vs Night Owl: Different People Have Varying Circadian Rhythms
Although sunlight plays a significant role in your circadian rhythm, some people have a natural predisposition towards feeling more awake and energized in the morning (referred to as “early birds” or “larks”), while others are more active and alert in the evening (“night owls”). Opinions on this vary and there is a wide range in between, but it’s generally assumed that more people fall closer to the category of “early birds.” It’s also true that with standard school, work and business hours, society functions more to their benefit.
Additionally, circadian rhythms tend to change and evolve with age. Children, teenagers, adults and seniors all have different times that their bodies want to get up, eat, go to sleep, etc.
Disruptions to Circadian Rhythm
Shift work with frequently changing hours, jet lag from switching time zones, certain medical conditions, or even simply choosing to stay up late one night are all things that can throw off your circadian rhythm. In the long run, studies show this can negatively impact your health in a variety of ways.
Many of us often look to catch up on lost sleep on the weekends, unfortunately averaging 8 hours of sleep per night is not the same thing as getting 8 hours of sleep every night. In fact, “sleeping in” one or two days a week can actually disrupt your body’s internal clock.
How to Find your Circadian Rhythm
How do I fix my circadian rhythm? Resetting circadian rhythm, or in truth finding out what your natural circadian cycle really is, is easy if you have the time. Simply go to bed when you feel tired, and don’t use an alarm to get up in the morning. Do this for several days, and eventually you’ll discover exactly when your body wants to be asleep.
Maintaining your Circadian Rhythm: Sleep Consistency
Exposing yourself to natural light in the morning and avoiding screens and other sources of artificial light in the evening prior to bed will help reinforce your circadian rhythm.
The most important thing you can do to maintain it is focus on your sleep consistency--going to bed and waking up as close to the same time each day as possible.
Your sleep quality will improve and your body will perform better when it can anticipate the onset of sleep every night. Much more on this below...
Health Benefits of Sleep Consistency
A 2017 Harvard study discovered that students with consistent sleep and wake times had higher GPA’s than others, despite not actually getting more sleep. WHOOP used this as motivation to begin tracking sleep consistency, and the results we’ve found are staggering. Our data shows that better sleep consistency contributes to:
- More REM sleep, the mentally restorative stage of sleep
- Increased slow wave (deep) sleep, the physically restorative stage
- Lower resting heart rate
- Higher heart rate variability (HRV)
“I started doubling down on sleep consistency and I’ve seen a huge, huge improvement in the time I’m spending in deeper stages of sleep, and I’m actually spending less time in bed.” - Podcast 17: The Circadian Rhythm Sleep Hack
The WHOOP Sleep Coach Incorporates Your Circadian Rhythm
WHOOP is 3rd-party validated to accurately track your sleep in great detail, including a breakdown of the amount of time you spend in each stage of sleep. The app’s Sleep Coach monitors your circadian rhythm and uses it to make nightly recommendations for exactly how much sleep you need, as well as precisely when to go to bed and wake up in order to maximize your sleep consistency and get the highest quality sleep possible.
WHOOP is not a medical device, our products and services are not intended to diagnose illness or any other health problems, and should not be used as a substitute for professional medical advice, diagnosis or treatment.