How Sleep Affects Your Hormones & Brain Function: Doctors Weigh In
It's a well-known fact that a good night's rest can leave you feeling energized, restored, and ready to take on even the most hectic of days. But what is it about sleep that gives us these superpowers, and leaves us feeling groggy and dazed in its absence?
Here, the medical community fills us in on all the magical ways sleep shapes our hormone production, brain function, and immune response starting the moment our heads hit the pillow.
1. Your body fights weight gain.
Dr. Eva Selhub, a physician and lecturer at Harvard Medical School, reminds us that sleep turns down the stress system, lowers cortisol levels, and regulates hormones that keep our weight in check1.
"In addition to a slower metabolism, sleep deprivation may stimulate more food cravings and an increased appetite. This is likely due to increased levels of ghrelin, the hormone that sends messages to your brain that you should eat more and that you are hungry; and lower levels of leptin, the hormone that signals your brain that you are full and to lower your appetite," Selhub says. This is why people who sleep less than six hours a day have an increased likelihood (almost 30 percent!) of becoming obese compared to people who sleep 7-9 hours.
2. REM takes over your body and mind.
About 90 minutes after you fall asleep, you enter the incredibly dreamy realm of REM. Breathing becomes shallow, the muscles in your arms and legs relax, and your brain has the chance to dream and process and store memories. This deep stage of sleep is so important that your brain works to make sure it isn't disrupted by actively shaping your dreams. For example, the sound of an alarm clock may seamlessly play into your dream as a church bell or radio, so that you can keep sleeping.
You can work with your body to make sure that your bedroom doesn't disrupt this important stage of deep sleep by banishing excess light and investing in a comfortable mattress. Essentia's natural memory foam mattresses were uniquely designed to reduce motion transfer and pressure points to help you comfortably sleep through this incredible cycle. In fact, Essentia’s patented technology is designed to extend this phase of your sleep cycle.
3. Inflammation is kept at bay.
Studies show2 that even one night of mild sleep deprivation can trigger an inflammation response. Chronic inflammation is associated with everything from weight gain and digestive problems to brain fog and those pesky under-eye bags.
4. Your ability to process carbs changes.
Did you know that your ability to process carbs changes with sleep? Immunologist Dr. Amy Shah explains that sleep deprivation impairs the ability of fat cells1 to respond to insulin, making people less tolerant of sugars.
5. Your immune system recovers.
Your immune system actually heals itself during your nighttime ZZZs. A process called adaptive immune response revs up as you sleep, fighting off anything you might have come in contact with that day.
6. Your body temperature drops.
Once you begin to drift off to dreamland, your body temperature naturally decreases by 1 to 2 degrees, reaching its lowest point about two hours before waking time. This is its way of conserving energy during sleep. However, if your surroundings are too warm, you'll struggle to reach this optimal temperature.
Making your bedroom even 0.4 degrees Celsius cooler has been shown to3 make a huge difference. Combine a cooler room (around 60 to 67 degrees) with a temperature regulating mattress like Essentia's, which has proprietary natural memory foam that allows heat to flow away from the body and permeate through the mattress core, and you have a recipe for deep, restorative sleep.
7. The brain processes the day.
"Many don't know that lack of sleep or disturbed sleep hygiene can cause structural changes4 to the brain5," explains integrative neurologist Dr. Ilene Ruhoy. "Insufficient sleep may result in a reduction of the cells in the dentate gyrus of the hippocampus, which results in memory impairment."
8. Hormones can take center stage.
The body produces testosterone, estrogen, and progesterone during sleep, especially during that deep REM stage. In addition to promoting a healthy sex drive in men and women, testosterone has a protective effect on the heart and reduces inflammatory proteins that can cause heart damage.
9. Memories are sorted and stored.
Dr. Michael Breus, Ph.D., SleepScore Labs advisory board member, says that deep sleep gives the brain time to filter out unnecessary information and determine what to keep for decision-making later on. Furthermore, during REM sleep, your brain moves information from your short-term memory to your long-term memory. "The benefit is that there's information storage for later use, and the unnecessary information is basically not taking up space in your internal hard drive," he says.
10. Your body turns glucose into fat.
In addition to repairing muscles, the growth hormone released during sleep helps control cellular repair and converts leftover glucose to fat, Breus adds. "This fat keeps the body functional while it sleeps, and it's the energy that you may use if you go for a morning run on an empty stomach." On the other hand, you'll likely wake up groggy, hungry and ready for a nap when your body doesn't have the chance to fully process this glucose.