I just listened to an in-depth discussion on the importance of sleep with Dr. Rhonda Patrick of FoundMyFitness and Dr. Matthew Walker, professor of neuroscience at UC, Berkeley, and the Dir. of the Center for Human Sleep Science. I think this is a subject that we can never have enough information about. It is so vital to everyone’s health. Especially for women after 40!
In his book, “Why We Sleep: Unlocking the Power of Sleep and Dreams,” Dr. Walker shares what he describes as the four pillars of sleep: depth, duration, continuity, and regularity.
Depth – deep slow wave sleep
Duration – length of sleep
Continuity – amount of continual sleep. Ex. eight hours of sleep across nine hours is fragmented sleep. Eight hours in one session of eight hours is better.
Regularity – going to bed and waking up at the same time
If you’re reading this and thinking all is lost, you’re not alone. One out of every two adults in the developed world is sleep-deprived. (I write this having awakened at 5AM this morning, unable to go back to sleep. Forgive grammatical errors… I’m tired.) But don’t get discouraged. What I loved about this talk was the sharing of great practical information to help all of us get back on track.
Why You Might Not Be Getting the Sleep You Need
Are you sleeping against the typical day/night sleep cycle? The big example of this are shift workers who sleep during the day. They might be getting a good amount of sleep but not good quality of sleep.
What is your chronotype? Are you a morning or evening person? Thirty percent of the population are extreme morning people, thirty-forty mixed, and thirty percent evening. Here is an example of different sleep cycles for different chronotypes:
Morning Person: 9pm – 6AM
Evening Person: 1AM- 9AM
(Personally, I’m in the middle. My goal is to inch towards 10:30PM.)
By the way, your chronotype is genetic. It’s hard-wired into your genes. And, yes, society seems to reward the morning types. It’s the classics “Owls vs. Larks”. And it’s important to try not to fight your chronotype. There’s nothing we can do about a 9AM work start time, but try to work with what is natural for you as much as possible.
You will go through 90-minute sleep cycles starting with deep non-REM sleep first, then REM sleep. This repeats every 90 minutes. What changes is the ratio of non-Rem to REM during the cycles over the duration of the night. The first half of the night, the majority of those 90 minute cycles involve more deep wave sleep, which is incredibly restorative. More REM sleep occurs in the second half of the night. Capturing some sleep hours before midnight is ideal to get that restorative sleep.
Connection between Blood Glucose Levels and Appetite
There’s a link between lack of sleep and a higher risk for diabetes. People who sleep less than 7 hours have a higher risk of diabetes because insulin (a chemical released in the pancreas) instructs cells in the body to open up their glucose channels to absorb glucose. Once absorbed, your blood sugar drops. With insufficient sleep, the beta cells in your pancreas stop being sensitive to the signal of high glucose. Other cells (muscle and fat) also become resistant, which means the glucose continues to flow without efficient uptake.
When you lack sleep you will find yourself craving high-glycemic foods. Highly processed carbs means that they break down into … sugar. This sets the whole cycle off again! Your hormones will also get out of whack. Leptin is a crucial hormone that tells your brain when you are full. Ghrelin does the opposite. It lets your body know when you are hungry. After you eat, ghrelin goes down. When you are sleep deprived, leptin is impaired. You lose the satiety signal and ghrelin increases. You will find yourself overeating at main meals by, on average, 200-300 calories.
Light and Temperature
You want the right signals to wake you up and put you to sleep. Because we are exposed to so much artificial light our natural sleep/wake cycles can really get out of sync. Walker describes this as living life with a “dimmer switch on — not full light or full dark.”
It is so important to get natural sunlight in the AM. And, please don’t wear sunglasses. Light needs to hit your retina. This helps with maintaining your circadian rhythm. Thirty to forty minutes of outside morning light is ideal.
In the afternoon, you can put your sunglasses on. This helps with the gradual release of melatonin. However, this depends on your chronotype: lark or owl. If you go to bed around 10, put shades on at 4pm. We also need to turn down our lights at home. In every room. Try turning off half the lights in your house in the last hour before bed. This is an easy way to promote sleep.
Temperature is also important for better sleep. Always remember: the colder the better. Here’s great news for bath lovers: When you take a bath your extremities are very warm but your core body temperature gets lower. (Same with sauna use.) Walker describes how baths contribute to a “massive vasodilation – all of the blood vessels open up on the surface of your skin, and draws blood from core to surface.”
Your body needs to drop its core temperature by 2-3 degrees Fahrenheit. It’s much easier to fall asleep in a room that is too cold because it helps to drag your body temperature down.
The biggest lifestyle interaction with this disease is sleep. There are two main protein culprits that underlie the brain pathology that creates Alzheimers:
- Amyloid beta protein – clumps outside of brain cells, creates amyloid plaques
- Tau protein – sits inside of cells and creates a support structure that when compromised they become tangled and look like a tunnel collapsing
The medial pre-frontal cortex is where amyloid builds up, and it’s also the epicenter that generates deep sleep. As we age our sleep quality gets worse. (Gravity and sleep?!) And, it’s the type of sleep that is necessary for memory and learning. The less deep sleep we get, the more amyloid beta builds up … and the more forgetful we become.
What Walker shares is how if we can sweep out all of our brain’s metabolic waste, and stave off that amyloid build up. Our bodies have a natural waste system called our lymphatic system. But where does all the waste from our brains go? The Glymphatic system. This is made up of the glial cells that surround neurons and help with brain waste. Amyloid beta proteins are part of the metabolic byproducts that this system can clean up. While we sleep, our brain cells shrink by 60 percent, leaving room for our cerebral spinal fluid to help flush out waste.
Main Interventions You Can Do To Improve Sleep
- Light/Dark Regulation. Darkness helps release melatonin which helps trigger signals for rest and sleep. Three to four hours before bed try to decrease as much light as possible. Incidentally, one hour of iPAD reading at night drops melatonin production by 20%. You won’t reach your peak of melatonin production until three hours after you power down. You’ll wake up feeling less refreshed.
- Temperature – 63-66 degrees is ideal at night. Yes! It’s colder than most people think.
- Walk it out – don’t stay in bed awake. Your brain will start to associate bed and wakefulness. Get out of your room. Your brain needs to relearn the association of the bedroom as a place of deep sleep.
- Caffeine – Caffeine is a stimulant and keeps you awake. Coffee at night will drop your deep sleep by 20%. A key factor is the duration coffee’s half-life, which is 6-7 hours – the amount of time for 50 percent to be cleared from your body. So if you have a cup of coffee at noon, some caffeine will still be in your body at midnight. You’ll wake up unrefreshed and reach for 2 cups coffee to get you going. Vicious cycle.
- Alcohol – It’s a sedative. Sedation is not sleep. You are sedating your cortex. You are opening the door to sleep with many awakenings. Alcohol kills sleep continuity. It’s also one of the best chemicals for suppressing REM sleep besides Marijuana. (THC not CBD.) And sleeping pills come with increases of cancer and health concerns. Ten million americans take them every month. Again, you are sedating the brain. It’s not natural sleep.
So much to process, but the more you know, the more you can take action. I’ll leave you with my favorite quote from the talk, “Sleep is the Swiss Army knife of health”.
*Dr. Rhonda Patrick has a Ph.D. in biomedical science from the University of Tennessee Health Science Center, Memphis TN and St. Jude Children’s Research Hospital, Memphis TN. Her work focuses on the role micronutrient deficiencies play in diseases of aging, the role of genetics in our health, sleep, fasting, insulin, vitamin d, and so much more. Her site is FoundMyFitness. I highly recommend her videos and podcasts.