In this day of rush-rush-rush, we tend to neglect the things that are important to living our best, most healthy life. When we’re younger, we tended not to think about how these things would affect our longevity, but eventually it all catches up with you. Recently, we’ve talked about getting the sugars out of our diet and the importance of movement. All very important to aging gracefully and improving our longevity. But in my opinion, sleeping well is the most important health habit to develop.
For me, in my younger days, no matter how well I was eating or how much I exercised, I was full-on from morning to evening, and I was good about getting a physical workout most days.
However, when bedtime came, I was so excited about all the things that I was doing that after 17.5 hours of go-go-go, I didn’t know how to give my brain a break. I couldn’t turn it off. My brain was so fired up that even when I slept, I didn’t sleep deeply. My brain was taking all my body’s energy, even during sleep. I call this “fire brain”.
I woke up tired, my weight was going up even as I tried to diet, my blood pressure and fasting blood sugar levels were rising—even my cortisol levels were getting higher. My lack of sleep was actually interfering with my body’s essential healing and cleansing processes (though I didn’t know it at the time).
Any of this sound familiar?
If the purpose of sleep is to knit the cares of the day (a nod to Macbeth) into something you can put away as a memory and to refresh and clear the mind, I was definitely doing something wrong. If I hoped to live a long and happy life, something, maybe everything, had to change.
Who Needs Sleep? The Matter of Dirty Brains, Stressed Hearts and Bodies, and Emotional Overwhelm
In our 20s and 30s, it was a badge of honor to say we pulled all-nighters or kept going on three or four hours a night. Being overbooked was the ideal for many of us and it was popular to think that sleep was a waste of time. Whatever the health impact of pushing your body’s limits, you could still manage; you had reserves of healthy capacity in your heart, lungs, circulation, and most important, your brain. You had an excess supply of neuron and cell production. You burned off some cells and replenished them faster than you could use them—until you got to a certain age, around 30, when the balance tipped. After that, your body started using more cells than it could replenish.
All of us were hurting ourselves and perhaps, ever so slightly, shortening our lives, but we didn’t know it. We hadn’t heard experts like James Maas, PhD, formerly of Cornell University, say, “Good sleep is the best predictor of life span and quality of life.” Sleeping well is that important to our health and the actual cellular functioning of our bodies.
Now comes the time of reckoning.
Over the years, scientists have made amazing discoveries about what actually happens when we sleep. New techniques that peer into the brain show that sleep is essential for at least three distinct functions:
- Cleansing the brain of toxic buildup
- Storing memories
- Maintaining metabolic balance for neuron and cellular health
That’s pretty powerful stuff. The results in terms of well-being are real: lack of sufficient or deep enough sleep leads to greater risk of brain and memory impairment, heart disease, insulin and hormone imbalances, and the emotional fallout of worry and anxiety when the mind can’t or won’t turn off.
The Washing Machine Metaphor: A New Understanding of Brain “Washing”
I tell everyone I meet: your brain needs sleep to detoxify. That’s what the new brain imaging studies are showing us. Our bodies need to cleanse themselves. Our skin naturally sloughs off its top layer. Our digestive system rids our bodies of waste and toxins. The body uses the circulatory system for transporting blood and nutrients to where they need to go and uses the lymphatic system for clearing the body of wastes. However, it was believed for a long time that the brain was the only part of the body that didn’t have its own built-in lymphatic system—just a circulatory one.
Neuroscientist Jeffrey Iliff, PhD, and his team at the University of Rochester Medical Center, discovered that the brain does have its own washing system, which they call the glymphatic system. It has a unique role in cleansing our brains—at night when we’re asleep!
Each of our cells functions like a miniature factory, producing chemicals and fueling processes in our bodies. Like factories, and like all the cells in our bodies, our brain cells also produce waste that must be flushed out.
Dr. Iliff and his team discovered that the human brain has developed an ingenious system for ridding itself of waste. The clear cerebrospinal fluid (CSF), which is found between the cells in the brain, carries the waste along the outside of the blood vessels. But Dr. Iliff discovered that when the brains of mice go to sleep, their brain cells shrink and the space between them expands, allowing the fluid to rush through and clear out waste. During the day, the brain puts off this cleansing process. When you go to sleep at night, your brain flushes its dead cells out of your body. If your sleep is interrupted, it can’t wash your dirty brain.
When you lack sleep, two things are going on—both of them bad. The first is that your body is not allotted the time it needs to produce new cells. The second thing is even worse. You see, the waste in the brain includes amyloid-beta, a protein that is continuously produced in the brain, which can build up and aggregate as plaque in the spaces between the brain’s cells. If you’re not sleeping well, you don’t allow the full wash cycle to take place, so that sticky plaque clumps and clusters—and guess what happens? Though the science is not yet definitive, it likely results in memory loss, Alzheimer’s disease, dementia, and other “dirty brain” diseases like Parkinson’s, which are caused by, correlated to, or sped up by the lack of sleep.
Researchers at Johns Hopkins studied 70 older adults, average age 76, and using brain scans, they found that the participants who said they got the least sleep, less than five hours a night or who did not sleep well, had higher levels of amyloid-beta in the brain than those who slept more than seven hours a night.
While the researchers couldn’t say whether poor sleep caused the buildup or the buildup caused the poor sleep, or if both effects were true, the study’s lead author, Adam Spira, PhD, explained, “These findings are important, in part because sleep disturbances can be treated in older people. To the degree that poor sleep promotes the development of Alzheimer’s disease, treatments for poor sleep or efforts to maintain healthy sleep patterns may help prevent or slow the progression of Alzheimer’s disease.”
So, How Much Sleep Do We Really Need?
As we age, our sleep needs change. Newborns require 14 to 17 hours of sleep a day, teenagers need 8 to 10 hours and adults generally need 7 to 9 hours. Except for about 2% of the population (odds are, you aren’t in that group), everybody absolutely needs at least seven hours of sleep a night. Sleeping less than 6 hours or more than 9 hours is associated with increased health problems and mortality, so if either fits your sleep pattern, you might want to look into whether you are getting too little or too much sleep.
Sleep becomes ever more important as we age. In our late 30s, the deep, memory-strengthening and restorative stages of sleep start to decline. While the common belief that humans need less sleep as they age is a myth, older people do tend to sleep more lightly and for shorter durations. Thus we have to do everything we can to maximize our sleep in order to protect our minds, cell generation, and the peak functioning of our bodies.
Deep Sleep and REM: Timing Is Everything
Getting enough sleep is only part of the sleep issue. Getting the right kind of sleep is just as important. A full 20% or 25% of the energy our bodies generate supports the activities of our brains. When we get “good” sleep, that energy can be used to support and replenish all the systems in our bodies, including essential cell growth. It’s a big if, however, because so many of us have trouble getting a good night’s sleep, as my fire brain experience showed.
So what is “good” sleep?
Sleep patterns are described in terms of eye movement. REM, or rapid eye movement, sleep is the stage of sleep that involves dreaming. Non-REM sleep happens in four stages: (1) drifting in and out of light sleep; (2) slowing of brain waves and disengaging from surroundings; (3) extremely slow brain waves (delta waves), interspersed with smaller, faster waves; and (4) almost exclusively delta waves. Stages three and four are what experts consider deep sleep, which is the most restorative, “good” sleep we are aiming for. You can track these stages with a sleep monitor. According to the National Sleep Foundation, you should be getting about 15% to 25% of REM sleep and 12% to 25% of deep sleep each night.
It’s during deep sleep that our blood pressure drops and our breathing slows. The blood supply to muscles increases and tissue growth and repair happens. Hormones that regulate growth and appetite get released. The brain takes the stimulation, events, learning, and insights of the day, sorts them out and processes them to determine their larger meaning, and transfers them to places in the brain where they are stored long-term.
REM sleep alternates with the four stages of non-REM sleep. During REM sleep, our breathing is rapid and irregular, our eyes jerk rapidly, and our limbs become immobile and relaxed as the brain’s usual signals to the muscles are turned off.
As the night wears on, our sleep cycles shift. Longer periods of deep sleep tend to occur in the early part of the night, before midnight, and longer periods of REM sleep happen toward daybreak. That’s true regardless of when you go to bed. If you generally retire after midnight, even if you sleep eight hours, you may not be getting enough of the deep, restorative sleep you need for peak cognitive function and memory.
Wellness Warriors, in my next blog, I will share with you 10 tips to getting better sleep. You’ll definitely want to catch that one! But tell me, how many hours of sleep do you average every night? Just curious!
Live Well, Live Long,