As a Pediatric Sleep Specialist, I often talk with my clients about body rhythms. That’s because when it comes to helping children get the kind of restorative and consolidated sleep they need to be happy and healthy, we must help them sleep when their bodies dictate.
Let’s take a look at how two kinds of rhythms, circadian and homeostatic, influence our sleep patterns.
What makes our bodies need sleep? What predicts how many hours of sleep we require each day, and when it’s time to wake up? It’s easier to understand the answers to these questions, when we first understand how the body’s two internal sleep drives, the homeostatic sleep drive and circadian rhythm, regulate our sleep and wake schedules.
Sleep Drives Explained
Homeostasis is any self-regulating process by which biological systems strive to maintain stability, while optimizing conditions for survival. Sleep, like body temperature and blood sugar, is regulated internally. Healthy Sleep, a resource from the Division of Sleep Medicine at Harvard Medical School and WGBH Educational Foundation, uses the following example to explain the Homeostatic Sleep Drive:
“When body temperature falls, blood vessels constrict and we shiver; when blood sugar levels rise, the pancreas secretes insulin; when we remain awake for an extended period of time, structures in the brain promote sleep. Furthermore, the duration and depth of our sleep vary according to the quantity and quality of sleep obtained previously.”
Circadian Rhythm is often referred to as the “body clock.” It is a 24-hour cycle that is vital in determining when we sleep and when we are awake. Many environmental factors can alter circadian rhythms, most notably sunlight, but also temperature, shift work, medications and time zone changes.
What Happens with Too Little Sleep?
When we sleep, and how long we sleep, is the result of how homeostatic and circadian rhythms combine. The Brain from Top to Bottom, talks about how homeostatic debt, “increases as a function of how long you have been awake and decreases as you sleep. In other words, the longer you stay awake, the greater the pressure you will feel to go to sleep.
Commonly known as sleep debt, homeostatic debt “also explains why, if you stay up all night, not only will you sleep longer the next night, but your percentage of deep sleep will be higher.”
The phase of your circadian rhythm also “greatly influences the onset, duration, and quality of your sleep. These phases are governed by your biological clock, whose rhythm is endogenous, but is reset regularly by daylight.
Your biological clock “produces a cycle lasting about 24 hours, where the optimal times for falling asleep, dreaming, waking up, and doing work, occur over the course of each day. For example, your circadian oscillator will typically make you noticeably sleepier from 1:00 PM to 4:00 PM, and even sleepier from 2:00 AM to 5:00 AM.
Sleep for Success
“Under normal circumstances, your periods of activity and rest are in phase with the alternation of day and night and your “circadian” pendulum and your “homeostatic” pendulum are in synch. You sleep well when you fall asleep, and you function well when you wake up. But when this relationship is disturbed, and the two pendulums are no longer in synch, then the quality of your sleep and your performance when awake, deteriorate significantly.” http://thebrain.mcgill.ca/flash/capsules/outil_bleu24.html
Applying Sleep Science to Your Children
As parents, you know that there are many external factors that can disrupt these two pendulums within your children,and with the balancing act of school, daycare, extra-curricular activities and other family commitments, it can be difficult to get back on track.
The science of sleep can be difficult at times to navigate. If you feel your child or family could benefit from the assistance of a child sleep specialist, take a look through my sleep success plans or contact me for further information.
Please let me know if you found this information helpful.
Angela Walsh is a Family Sleep Institute, Certified Infant and Child Sleep Consultant and the founder of Babes in Sleepland. She helps sleep deprived babies, children and families, get back on track and get the sleep they need and desire. To learn more about Angela and how she can help you, visit her website: babesinsleepland.com. Also get sleep tips, the latest research on baby and child products, and be part of her weekly Q and A at her Facebook page: Babes in Sleepland.