I have struggled for more than a decade with sleep, like many of us. Sleep has not been my friend. It’s absolutely more important than just getting a little rest. It’s fascinating to really understand how it impacts our bodies. Nobody can explain it better than a doctor who specializes in hormone balancing. Dr. DuMoulin explains what we need to understand about sleep…
“A good laugh and a long sleep are the two best cures for anything.” Irish Proverb.
We all know the feeling: yawning all day, dragging at work, realizing you are in a conversation but have no idea what the other person is talking about, or how long they have been talking for that matter. Lack of sleep, poor sleep, or sleep deprivation – all ways to describe many of our daily lives. But why? Why does having too little sleep affect us so strongly? Why do we need so much sleep? What happens if we keep depriving ourselves of sleep?
While we sleep our brain “cleans” itself:
Many biological functions occur only during sleep. New research has suggested that while we sleep, our brain cleans out the byproducts of neural activity (thinking). Our brain is protected by the Blood-Brain-Barrier; this is a very selective wall that keeps most of what we encounter daily out of our brain – good thing! The downside to this selective set up is that the brain is also disconnected from our body’s lymphatic system. The lymphatic system is a collection of lymphatic vessels throughout the body that circulate lymphatic fluid (plasma that protects us against infections and the spread of tumors and assists with waste removal and toxin clean up). Since the brain does not have access to the lymphatic system, the brain must do it’s own form of clean up.
The latest research suggests that the brain has it’s own network system (currently termed the glymphatic system – the “G” in reference to glial cells which support and protect the brain) that circulates cerebrospinal fluid around the brain and down the spinal cord. While we are awake, the cerebrospinal fluid is flowing very slowly due to less space while other functions occur. When we sleep, the brain is less active and the cells actually shrink up to 60% (currently only mice studies available), therefore providing more space for the cerebrospinal fluid to flow. In the mouse study, the cerebrospinal fluid swelled to more than 20% the original volume and flowed 10x faster than during the day. By increasing the volume and the rate of flow, the brain is able to bathe itself in cerebrospinal fluid all night long, cleaning out the waste and byproducts built up by a long day of thinking.
Sleep and Growth Hormone:
Besides bathing our brain, the rest of our body has unique functions that only occur while we are asleep. Growth Hormone, a hormone that stimulates growth, cellular regeneration, and cellular reproduction, peaks while we sleep. It assists with the conversion of thyroid hormone, bone mineralization, supports the immune system, stimulates organ, bone, and muscle growth, stabilizes blood sugar, and plays a role in homeostasis (balance within the body). Chronic poor sleep or sleep deprivation suppresses the release of Growth Hormone, particularly in adulthood. Without a stable nightly release of Growth Hormone, we can experience an increase in fat mass, a decrease in muscle mass, a decrease in energy levels and a decrease in overall quality of life.
Sleep, Resting Heart Rate, and Blood Pressure:
Another very important biological function that occurs while we sleep is that our heart rate slows down. Our heart is never allowed to rest; if it does, we have a major problem. Since the heart is constantly beating, anything we can do to give it a rest will prolong its ability to work. When we sleep, our heart is allowed to slow down and gets a break from pumping against gravity and the stresses of our day. Our blood pressure decreases at night as well. If we consider that the heart has a finite number of beats before we die, reducing the number of times it beats as well as how hard it has to work to beat will be of great benefit. A 2011 European Heart Journal review of 15 medical research studies found that those who slept less than seven hours per night had a 48% increased risk of developing or dying of coronary heart disease and a 15% increased risk of developing or dying from a stroke after 7-25 years (depending on the medical study length).
What happens when we don’t get enough sleep?
In a nutshell, not getting enough sleep increases our risk of heart disease, heart attack, stroke, heart failure, irregular heartbeats, high blood pressure, and diabetes. We experience a decrease in cognitive functions such as memory, concentration, alertness, attention, decision-making, and reasoning. We can become overly emotional as it becomes difficult to put our emotional experiences into context of the situation. We become clumsy as we have slower and less precise motor skills, reaction times, and altered depth perception. We have a lowered pain threshold making us more sensitive to pain and making the pain seem more intense.
Sleep and Cortisol Regulation:
Cortisol levels should spike when we first wake up then slowly decrease during the day until it reaches the lowest levels at night when we are sleeping. Cortisol is our stress hormone; it allows us to run or fight or be on alert throughout the day. Physiologically, Cortisol increases blood sugar, suppresses our immune system, and decreases bone formation. When we don’t sleep well or don’t sleep long enough, the Cortisol levels begin to rise during the night. Increased levels of Cortisol can age our skin faster, help us gain weight, increase anxiety levels, and demolish our libido. Low cortisol levels can do the above as well. The body likes balance! Too high of levels can look similar compared to low levels.
Sleep and Weight Gain:
Another way lack of sleep can help us gain weight is through other hormonal changes. The hormones Leptin and Ghrelin stimulate hunger and appetite. These hormones are generally shut off while we are asleep. If we are not sleeping well or long enough, these two hormones are stimulated when they should not be. Whether we end up eating more because we are awake longer or we snack when we normally wouldn’t experience hunger, the stimulated appetite, and consequential excess calories will begin to add up.
Sleep and the Immune System:
The immune system becomes compromised with lack of sleep. A 2009 study found that those who slept less than seven hours nightly were almost three times as likely to catch the common cold than those who slept at least eight hours. Sleep deprivation affects the regulation of signaling pathways associated with the immune system. In a 2013 study, researchers found that sleep restriction altered the expression of 117 genes, at least a quarter of which directly impact the immune system. Lack of sleep also decreases the activity level of white blood cells (immune fighting cells) available in the blood stream. Multiple studies have shown that sleep deprivation increases the amount of pro-inflammatory cells and decreases the amount of anti-inflammatory cytokines that protect against inflammation. Inflammation is a long known cause of many diseases processes as well as a compromised immune system.
How much Sleep Do I Need? How Can I Improve My Sleep? Pop over to Dr. Du Moulin’s blog to read the rest of her advice.