Sleep for Healthy Aging
Sleep for Healthy Aging
How Sleep Cleans Your Brain, Protects Your DNA, and Promotes Not Only Lifespan but Healthspan
Aging is such a hot topic right now. Deservedly so, as people are living longer than ever, and the average age of Americans is increasing. Not only do we want to have a long life, but a healthy life too. There’s a new term being used: “healthspan” – the part of your life that you are generally healthy. Ideally our healthspan is almost as long as our lifespan. Quality sleep without sleep disorders, along with enough hours of sleep night after night, can extend our healthspan in several ways. Dive in with me.
Protective Effects of Slow Wave Sleep
Let’s start by talking about slow wave sleep (SWS). Slow wave sleep is also called ‘deep sleep’ or ‘stage three sleep’. During stage three sleep the brain waves are very high amplitude and slow, quite different from the short and fast brain EEG patterns of wake. This difference makes it very difficult to wake up out of stage three sleep. If you've ever woken up to an alarm and just felt completely tired and had difficulty getting with the program, it's probably because you woke up out of stage three sleep.
What happens over the lifespan is that SWS declines significantly. First, in the teen years by about 40%. Then it continues to decline over the lifespan, so seniors are getting just a fraction of the SWS they got in earlier life. In part, that is why seniors often don't feel like they're sleeping very deeply.
There are two mechanisms by which deep sleep helps us age healthy. One is that 75 to 85% of our total growth hormone is secreted during deep sleep (1). Growth hormone is important for physical repair. It keeps our muscle mass and bone, influences metabolism and blood sugar control, and other aspects of physical health. As deep sleep is declining over the lifespan, so is our growth hormone. That is partly why aging accelerates as we get into our senior years and beyond.
Sleep is Time to Clean the Brain
In the brain we have what’s called the ‘Glymphatic System’ or ‘Neuroglymphatic System.’ Similar to the lymph system in the body that clears toxins, the glymphatic system clears metabolic waste products from the brain (2). This glymphatic system opens up to almost twice it’s volume primarily during deep sleep. Some of the very important waste products that are cleared from the brain during sleep are the beta amyloid proteins that can accumulate in the brain and contribute to Alzheimer's disease (3). If a person is not sleeping well (or enough) in midlife, they are at higher risk of developing Alzheimer's disease. Part of the mechanism is that when a person is not sleeping well, they don't have as many hours in deep sleep when the glymphatic system is clearing those beta amyloid proteins.
Melatonin is Anti-Aging
When we are asleep, our melatonin levels rise quite significantly. This is important as melatonin is anti-inflammatory (4). Chronic inflammation is a primary contributor to chronic disease. We need melatonin levels to be elevated during sleep by having sufficient darkness in the night. We also need adequate hours of sleep for our melatonin to be elevated. This pineal melatonin circulates throughout the body serving as an anti-inflammatory.
Sleep Protects our DNA
DNA is important in both the replication of cells, and for accurate cellular function. On the end of our DNA there's a little section called a telomere. The telomere is inactive, ie. it is not replicated, but rather it's protective. An anology I think of is the larger metal end of a zipper. If that metal end ever comes off, the zipper no longer works properly. Similarly, without the telomere, the DNA starts to fray. Telomeres shorten with age, which is a sign of aging. Young healthy children will have much longer telomeres than older people will. You want to keep those protective caps on your DNA as long as you can, so that your cells are replicated correctly which preserves your health.
Sleep is relevant because when a person either isn't sleeping long enough, or they have a sleep disorder, their telomeres will be shorter. With obstructive sleep apnea, short sleep duration, and insomnia, telomeres are shortened. This is a very interesting area of research because we now know that telomeres are shortened even in infants whose mothers had obstructive sleep apnea during pregnancy (5). This is a sign of advanced aging compared to children who developed without obstructive sleep apnea.
Sleep Skills:
Thankfully, some of these factors that contribute to aging are within our control. Use these sleep skills to protect your healthspan:
1. Make sure that you're getting adequate sleep, the ideal number of sleep hours for you every night. We talked about the five domains impaired by insufficient sleep last week, so this effort will pay off more immediately too.
2. Treat whatever sleep disorders you have been diagnosed with. If the recommended treatment isn't working for you, go back to your health care provider and find out what your other options are. This time will be worth it in both the short term and with your long-term aging.
3. Get proper darkness in the evening and during sleep so that your melatonin can be elevated to optimal levels for that anti-inflammatory effect throughout your body. As chronic inflammation contributes to chronic disease, that anti-inflammatory action is critical.
Talk to you next week, and until then Sleep Well,
Dr. Catherine
Each Saturday morning tune in to Youtube Live for a discussion of that weeks’ topic at 8am PST / 11am EST. (Apologies for having technical difficulties last Saturday, see you on the 19th!) Be A Skilled Sleeper - YouTube
For short informational tidbits and tips daily, check out Instagram Dr. Catherine Darley (@skilledsleeper) • Instagram photos and videos
Upcoming topics:
- How women’s hormones impact sleep, and sleep impacts reproductive disorders, particularly in shift working women.
- Health hazards of artificial light at night and the strategic use of Light and Darkness for health.
- Restless Legs Syndrome, other sleep movement disorders, and current therapies from exercise to nutrients to allopathic medicine.
References:
1. Human growth hormone release: relation to slow-wave sleep and sleep-walking cycles - PubMed (nih.gov)
2. The Glymphatic System: A Beginner's Guide - PubMed (nih.gov)
3. β-Amyloid accumulation in the human brain after one night of sleep deprivation - PubMed (nih.gov)
4. Aging, Melatonin, and the Pro- and Anti-Inflammatory Networks - PubMed (nih.gov)
5. Telomere length and fetal programming: A review of recent scientific advances - Whiteman - 2017 - American Journal of Reproductive Immunology - Wiley Online Library
My videos are for informational purposes only. I am not providing medical advice, and my videos should not be used as substitutes for professional medical advice, diagnosis, or treatment. If you have any questions about your health or medical conditions, please contact your health care provider.