Sleep

Sleep is a no-brainer. It is essential for survival.

In Ayurveda, your total wellbeing hinges on getting ample, high-quality sleep. Similarly, in conventional science, there is an indisputable link between sleep and health. The consequences of sleep deprivation range from short-term irritability to long-term memory loss. It is linked to numerous chronic and even life-threatening conditions.

So, with all of this in mind, why are 40% of us sleep deprived? Why isn’t sleep everyone’s top priority? The reasons are varied and complex. But the root cause could be quite simple—a lack of understanding of exactly what your body does during its “down time.” In the grand scheme of things, awareness of sleep’s vital importance to your physical, mental and emotional functions should place it at or near the top of your priority list. This write-up provides Ayureka’s explanation of what goes on in the bedroom.

Why Do You Sleep?

Over the years, conventional science has developed many theories as to why you need to sleep at night. These range from having a primal instinct and need for safety during dangerous times of day, to theories about sleep’s restorative properties. We still don’t have a concrete understanding of why we need sleep. Modern researchers continue to uncover substantial evidence about what happens physiologically when you are asleep, as the body repairs and recharges itself. They know sleep is tied to boosting immunity and aiding growth and development. And it is well understood that sleep deprivation impacts your entire being—from cognitive impairment to impulsive behavior to obesity and heart disease.

How Does the Sleep Process Happen?

Your body is hard-wired to sleep. Evolutionary forces have tied your desire for rest to nature’s daylight/nighttime cycle. In other words, you possess an innate Circadian clock that tells you when your body should go to bed and when it is time to wake-up.

This works because your brain’s hypothalamus, which is linked to the nervous and endocrine systems and metabolic processes, responds to light input from your eyes. An area referred to as the suprachiasmatic nucleus (SCN), or the anterior hypothalamus, tries to synchronize body rhythms with nature’s light cycles. These rhythms include sleep, body temperature, urine production and other functions. The SCN determines the time of day (i.e. nighttime) that you sleep. However, it does not actually induce sleep or trigger the function of waking.

The actual functions of going to sleep and waking up involve a complex series of interactions between multiple parts of your brain and endocrine system. Responding to a decrease in daylight, the body begins to “wind down” several hours before bedtime, enabling a natural drowsiness and an ease into sleep. This is, in part, tied to the release of melatonin. Similarly, a complex series of events enables you to gradually regain complete alertness in the morning.

In parallel with this natural cycle, your body has its own series of events leading to sleep. For example, recent research has shown that adenosine, which operates as a neuromodulator in the brain, builds up during daily activity to “inhibit bodily process associated with wakefulness.” In other words, as adenosine builds up during the day, it gives your body incentive to replenish energy during the night.

Sleep Phases

The body’s physiology during sleep is explained by monitoring eye movement and brainwave activity. Scientists define sleep through two major classifications:

• Non-rapid eye movement (NREM), also called “quiet sleep,” which occurs in three stages
• Rapid eye movement (REM) sleep, also called “dream sleep”

Throughout the night, the body travels through the NREM stages to REM sleep in a series of complete cycles that each last approximately 90 to 110 minutes. Different physiological processes take place during each step in a given cycle, so no two cycles are the same. This concept becomes easier to grasp when you understand more about NREM and REM. In the simplest of terms, NREM sleep “turns down” your brain so the body can repair itself. In contrast, REM sleep “turns up” the brain’s activity to enable it to refresh.

What Happens During Non-REM Sleep?

NREM sleep, or quiet sleep, takes place in three major stages:

• NREM Stage 1 (drowsiness): This is the initial stage of sleep, when the body and brain waves start to slow down and relax. Body temperature begins to drop. Eyes move slowly back and forth. Digestive functions begin to slow. And although muscles are relaxing, they can also twitch suddenly—an action called hypnic myoclonia. Overall you feel a drifting sensation.
• NREM Stage 2 (light sleep): Moving into this stage, brain waves continue to slow down, but increase in amplitude. You also experience small bursts of rapid waves lasting a couple of seconds. These burst are known as sleep spindles and are caused by interactions between the neurons of the thalamus and the cerebral cortex. In Stage 2 you feel a quiet state of readiness. Eye movement ceases during this stage. Blood flow continues to slow to the brain and is redirected to various parts of the body. You spend approximately 50% of your sleep time in this stage.
• NREM Stage 3 (deep sleep): Delta brain waves emerge during this stage. These are low-frequency (slow), high-amplitude waves. Initially, they are interspersed with smaller, faster waves, but as the stage progresses, the brain almost exclusively produces Delta waves. Muscles are relaxed. Heart rate is dramatically slowed down. Respiratory rates become more regular. This stage is also known as “slow sleep.” This is the time you are most groggy if suddenly awakened. (Note: This final NREM stage was once divided into Stage 3 and Stage 4. It is now commonly viewed as a single stage.)

It is becoming more accepted that NREM sleep, particularly Stage 3, is when your body goes into physical repair mode. As the body slows the brain function, it is able to direct energy toward restorative actions. Here are a few examples of what happens to your physiology during NREM sleep:

• During the day, your body produces more stress hormones, such as adrenaline and cortisol. High levels of stress hormones are linked to numerous chronic diseases. During NREM sleep, stress hormone levels drop.
• Trending in the opposite direction, your human growth hormone (HGH) levels increase during sleep. This signifies a shift toward restoration. HGH maintains and repairs muscles and bones by utilizing amino acids (protein building blocks). Body tissues are renewed faster during NREM sleep than at any time when the body is awake.
• General immunity improves with ample NREM sleep. Studies have shown that sleep deprivation leads to lower white blood cell counts and reduces the body’s cancer fighting agents.
• The skin’s metabolic rate is known to increase during NREM stages. This lends credibility to the idea of “beauty rest.”

What Happens During REM Sleep?

Although you dream throughout the night, REM sleep is widely understood as dream sleep. Ideally, your body should spend about 20% of the night in REM sleep. It is characterized by high brain activity. Dreams during this phase are longer, more vivid and more emotional than those that occur during NREM stages.

Numerous physiological changes happen during REM sleep. Eye movements are rapid. Heart rate, breathing and blood pressure are all more active and irregular. Your vital signs increase during this phase. Your brain actually consumes more oxygen than when you are awake.

During REM sleep, blood flow is redirected from the complex thinking areas of the brain to the areas that process memory and emotions. Before this happens, the Pons (located at the brain stem) sends signals to the thalamaus and cerebral cortex to shut-off of motor skills other than eye movement. Theories suggest that this directive is to prevent you from acting out your dreams.

Conventional science is just beginning to understand what happens during REM sleep. It is believed that the brain leverages this time to “clean up” its neuropathways. This could involve moving memory fragments, building new pathways and even shutting down ineffective connections. Since dreaming happens during the REM cycle, dreams might be considered your mind’s attempt to put together the fragments begin arranged.

A good analogy for REM sleep is defragmenting a computer. When a computer writes data to your hard-drive, it places it in sequentially ordered “blocks.” Fragmentation happens when a file is split between blocks. If the blocks are split or far apart, the computer takes longer to read that file. Defragmentation simply puts those blocks back into order for greater processing efficiency.

Reinforcing this idea, recent >research mentions that the “restorative function of sleep may be a consequence of the enhanced removal of potentially neurotoxic waste products that accumulate in the awake central nervous system.” From day-to-day, this might explain why one’s memory deteriorates rapidly when sleep deprived. Over an extended period of time, this may explain sleep’s importance in reducing risk factors for neurological diseases, such as Alzheimer’s.

Sleep Cycles: How NREM and REM Tag Team

As mentioned earlier, throughout the course of a typical night, your body moves through about five 90-110 minute sleep cycles. During each cycle, it transitions from the NREM phase to the REM phase, but the distribution of time spent in each phase, and in each NREM stage, varies from cycle-to-cycle.

Your body eases into its repair cycles. During the first part of the night, your body focuses on physical restoration and NREM stages dominate. By the middle of the night, when it is actually “doing its repair work,” NREM stage 3 dominates. Once the body has finished its restoration, the mind needs to “defrag.” Beginning in the very early hours of the morning, the body moves back through its sleep cycle. This time, REM sleep becomes a more dominant component.

What Happens When You Skimp on Sleep?

Many of us live in a state of sleep deprivation. We fall into the zone of 4-6 hours of sleep (or less) every night, day-in and day-out. And when chronically tired, it is easy to rationalize the afternoon “power-nap” or the weekend sleep-in routine. Our “always on” lifestyle contributes to this no-sleep/sleep-in cycle becoming an unhealthy way-of-life. Sleep during daylight hours has the tendency to throw your sleep cycle even further out of whack. At the same time, it doesn’t aid you in achieving the type of healthy, restorative sleep that is critical for your wellbeing. Researchers are beginning to document the consequences of not getting enough healthy sleep:

• Alzheimer’s: Researchers from The Johns Hopkins Bloomberg School of Health suggest that reduced sleep and poor sleep quality may be linked to increased build-up of beta-amyloid plaques in the brain. This is classically seen with Alzheimer’s disease. Previous research has linked disturbed sleep to cognitive impairment in older individuals. Healthy sleep may offset the risk of Alzheimer’s disease.
• Stroke and Heart Disease: Prolonged sleep deprivation increases the risk of suffering from a stroke or heart disease, according to a long-term study by the University of Warwick. This was based on the experiences of hundreds of thousands of people across eight countries. Findings include that people who sleep less than six hours per night and have disturbed sleep stand a 48% greater chance of developing or dying from heart disease and a 15% greater chance of developing or dying from a stroke.
• Diabetes and Obesity: A University of Chicago study found that building up a sleep debt over a matter of days can impair metabolism and disrupt hormone levels. After restricting healthy participants to four hours’ sleep for six nights, researchers found their ability to process glucose (sugar) in the blood had declined. In some cases it reached the level of diabetics. A follow-up study showed that short sleepers (6 ½ hours or less) needed to make 30% more insulin than normal sleepers to keep their blood sugar levels in check. Both studies were led by Eve Van Cauter, PhD, who termed sleep deprivation “the royal route to obesity.”
• Memory Loss and Brain Damage: The Neuropsychiatric Disease and Treatment journal reports that there is a well-established connection between sleep deprivation and decreased attention, working memory, long-term memory and decision-making. The Guardian reports that sleep deprivation can over-stimulate parts of the brain and even lead to permanent brain damage as the brain is forced to operate in a different state on a regular basis.

And this is just a short sampling of research linking sleep to health. Other studies have made the connection between sleep deprivation and depression, cancer and hypertension—to name a few common diseases.

Ayurveda: Back to Basics

For thousands of years, Ayurveda has been very clear about the vital importance of getting a good night’s sleep. It is regarded as one of the pillars of health. Ayurveda understands that health comes from nurturing your natural intelligence. Sound, ample sleep is one way to support your natural intelligence. Ayurveda offers time-proven methods to achieve this. Let Ayureka help you find your path to slumber. Here are a series of blog posts on this topic:

• A Wake-up Call on the Importance of Sleep
• Ayureka’s Sleep Diary
• Stop Losing Sleep to Sensory Overload: Tips for Calming Your 5 Senses
• 7 Ways To Help You Sleep In An “Always On” World
• 6 Compelling Reasons To Rethink The Nightly Drink
• Difficulties Falling Asleep? Look Here.

Summary

A good night’s sleep has been scientifically linked to good health. Modern science is beginning to understand that your body needs sleep to restore bone, blood and immunity to keep you healthy. Similarly, researchers are beginning to understand that your mind needs sleep to clean up its neurological pathway. This enables you to be alert and maintain cognitive abilities. It is also a contributing factor to maintaining a strong memory throughout life. Ayurveda has forever been clear about the importance of healthy sleep. And this ancient science offers time-proven methods to achieve it.

Keep an eye on our blogs for simple and easy-to-do ways of creating small and manageable changes to help improve your sleep.