Imagine being stuck deep inside a huge cave. For weeks you would have no communication with the outside world, no devices to tell you the time, and no idea whether it was day or night. What would happen to your sleep? Would your body completely lose track of time? Would you be able to get a normal night’s sleep? Would you end up in a random pattern of naps and wakefulness?
Believe it or not, this exact experiment has been performed. People lived in a cave for weeks. And even when they had no way of telling what time it was outside, people in this experiment still woke and slept in a roughly 24-hour cycle. How can the body know what time it is without a clock or sunlight? You can thank your very own internal clock, known as the circadian rhythm.
Circadian Rhythm and You
Every living thing on the planet has an internal body clock. It is the result of evolving on a planet with a 24-hour day/night cycle. For humans, the official timekeeper is located deep in the brain and is called the suprachiasmatic nucleus. One very important role for this clock is to make you feel sleepy and awake at different times of the day.
The typical circadian rhythm makes you feel increasingly awake as the morning passes. Between 1 and 3 in the afternoon, there is a feeling of fatigue and sleepiness that most people blame on lunch. But even if you didn’t eat lunch you’d feel this sleepiness because it’s due to your body clock’s signals. We don’t know why exactly the body does this, but it’s a common experience amongst all humans. As the afternoon and evening progress, your clock makes you feel very awake. This explains why you may feel tired just after lunch, and yet you typically feel quite awake after dinner. Thankfully, as the night approaches, the circadian rhythm makes us feel sleepy again, and it keeps us feeling sleepy until the next morning.
For some, the 24-hour cycle is a bit delayed compared to others. These people, deemed “night owls”, feel awake much later into the night than most, and have the desire to sleep in. In contrast, “morning people” have an early clock, so feel sleepy early in the night and wake up very early without difficulty.
Reset Your Internal Clock
We live in a world that caters to morning people. School and work typically start very early in the day, so it can be an advantage to have a body clock that is set a bit earlier.
Thankfully you can reprogram your internal body clock with some simply strategies, and the key is the proper timing of exposure to light. If you expose yourself to lights from televisions, smartphones and laptops at night, your brain thinks it’s still daytime outside, so tries to keep you up even later, and delays your circadian rhythm. The key is to avoid bright lights for at least 30 minutes prior to bedtime. In addition, getting plenty of bright lights in the morning helps move your brain’s natural sleep and wake time earlier.
Learning to manipulate your internal clock can be an important part to waking and sleeping at times that are most convenient to you. Adjusting your internal clock to fit your schedule can make a big difference in your sleep. Remember to unplug your devices at night to help your brain rest, but recharge in the morning with plenty of bright light. Your internal clock will thank you.
About The Author
Sujay Kansagra, MD is the director of Duke University’s Pediatric Neurology Sleep Medicine Program and author of the book “My Child Won’t Sleep.” Dr. Kansagra offers Daily Doze readers tips and insight about the importance of sleep, especially for kids who need plenty of rest to grow and develop. Dr. Kansagra graduated from Duke University School of Medicine, where he also completed training as a pediatric neurologist. He did his fellowship in sleep medicine at the University of North Carolina in Chapel Hill, before joining the faculty at Duke as an assistant professor. He specializes in treating a variety of sleep disorders, including sleep apnea, insomnia, narcolepsy and parasomnias. He shares advice on sleep, medicine, and education through his Twitter accounts @PedsSleepDoc and @Medschooladvice. When he’s not busy at work or on social media, Dr. Kansagra enjoys spending time with his wife and two sons. And yes, they are both great sleepers.
Best Night’s Sleep: Not just a sleep expert, but also an expert sleeper, Dr. Kansagra can sleep almost anywhere, thanks to years of sleep deprivation during medical school and residency call nights. But his best sleep is at home with his family, on a mattress he purchased at Mattress Firm long before he joined our team.