A remarkable Swiss Army knife of health and wellness, sleep is often an overlooked, under appreciated vitality elixir in today's modern World. In this article, I provide a brief science informed overview to improve your sleep hygiene practices. With over 30% of US adults reporting getting less than 6 hours a sleep on average per night, this unmet need is detrimental to all aspects of health. As Dr. Mathew Walker states, "The effects of sleep deprivation will seep into every nook and cranny of your biology." 

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As with all aspects of health and wellness, foundational education allows for science informed decision making. In my prior article, "The Ideal Morning Routine," I talked about the easily applied behavioral tools to improve your energy upon waking. I also mention the dual effects of increased daytime energy and setting the internal environment for the upcoming night's sleep. By implementing these behaviors on a daily basis, you control your internal clock to effectively release the chemicals responsible for both wakefulness and drowsiness when needed.  Light viewing, a primary staple in the morning routine, is further reiterated by Dr. Walker to "methodically reset our inaccurate internal timepiece each and every day."

Melatonin (often referred to as the "hormone of darkness') plays a crucial role in aligning the body's internal clock with the external environment, particularly in response to light and darkness. Melatonin helps to regulate sleep timing, but does not directly induce sleep. We do, however, have 2 primary sleep governing forces. The first, the suprachaismatic nucleus (SCN) uses light information to act as a central conductor of our internal biology and circadian rhythm. The second, adenosine, is built up throughout the day and directly responsible for the sleep pressure we feel later in the day. Although the latter is independent of the former, the resulting sleep pressure of built up adenosine aligns with the body's circadian rhythm. 

*Caffeine, a commonly used wakefulness agent, delays the realized effects of adenosine build up. However, it isn't until sufficient sleep is met that adenosine quantity is reduced rather than delayed.

Sleep Cycles & Benefits

We undergo various cyclical stages of sleep, each nuanced in their restorative efforts. Each stage of this cycle throughout the night lasts approximately 90 minutes with slight fluctuation as the night progresses. Early in the night, deeper Non-REM (NREM) stages 3 & 4 dominate, while stage 2 NREM and REM sleep prevail in the latter half of the night. Each stage impacts various aspects of physical and mental health, including memory consolidation, emotional regulation, and overall well-being.

*Each sleep cycle lasts approximately 90 minutes, alternating between NREM and REM sleep

NREM deep sleep is divided into four, depth increasing stages, dominating the first half of each night's total sleep time. The shortest, initiated by the transition from sympathetic to parasympathetic nervous system activation, last 1-5 minutes prior to entering stage 2. During this stage, body temperature drops, heart rate slows and the beneficial sleep spindles appear. The later stages NREM (3 & 4) are characterized primarily for memory consolidation, immune and physical restoration and brain waste clearance via the glymphatic system. 

Rapid Eye Movement (REM) Sleep is the principle stage where dreaming occurs. During this period of sleep, there is rapid, lateral movement of the eyes in conjunction with brain induced muscle atonia (complete relaxation). REM sleep provides a unique mental and emotional processing component not seen in other stages of the sleep cycle. This "overnight therapy" has significant benefits in emotional memory consolidation and creatine problem solving. The mood regulatory benefits of a "good night's sleep" is due to this stage of sleep through stress hormone regulation and emotional stabilizing effects. It is not inaccurate to refer to REM sleep as nature's in house emotional regulation and therapy session. There has also been shown to be an inverse relationship between REM sleep and all-cause mortality, further highlighted both the physical and mental benefits of sleep.

During REM sleep, the brain activity resembles that of a waking state, indistinguishable in their differences. Heightened areas include the amygdala, hippocampus and anterior cingulate cortex (ACC), whereas the prefrontal cortex is suppressed. You may be able to infer the internal mental environment this combination of heightened and suppressed areas of the brain may create during sleep. Unique to this phase of sleep, the brainstem send signals via the spinal cord to "lock" voluntary muscles in paralysis to ensure safety during dreaming. During our overnight memory replay, we reap the benefits of restoring emotional equilibrium while processing memories and information. This has been shown to improve emotional awareness as reported increased accuracy of correctly identifying other's facial expressions. 

*You may be familiar with the sleep paralysis felt while transitioning from sleep to waking. This is due to muscle atonic latency prior to fully waking. 

Learning Memory & Creativity 

The hippocampus (a small, seahorse-shaped part of the brain) plays a key role in both learning and memory, particularly short term memory. This memory banking and storing process appears to be dependent on the previously mentioned sleep spindles. Sleep promotes synaptic plasticity and NREM sleep facilitates the transfer of newly learned information into long term storage sites of the brain, the prefrontal cortex (PFC). When entering the next sleep cycle phase, REM sleep then takes fresh memories and collides with back catalogue, creating novel links and insights between unrelated pieces of information. Overarching insights form, taking into consideration the collective information as a whole. Sleep builds these associated networks to help one better understand how all things fit together. It should come at no surprise then that when deprived of sleep, subject's memory retention was impaired by 40% as shown in hippocampal activity. It goes without saying, but is worth reiterated that sleep moves the needle on almost every aspect of brain and body health.

"In the past 20 years I have not been able to discover a single psychological condition in which sleep is normal." - Mathew Walker

Sleep has a dramatic effect on mood regulation, cognitive function and overall resilience. Moderate sleep restriction has been shown to result in emotional instability and reactivity due to heightened amygdala activity and decreased connection of the PFC and amygdala. This 60% increased responsiveness of the amygdala, paired with reduced PFC connection, leads to disrupted emotional regulation, poor dietary selection and additional suboptimal physiological effects in otherwise healthy individuals. Baseline resetting, that is inaccurately having an overly positive recall of both time and quality of nightly sleep, is a very common occurrence is those who suffer from poor sleep quality. As with many aspects of health, it isn't until a significant concern and/or event occurs that we ultimately take action. 

REM Sleep and Emotional Health

In additional to sleep's emotional regulatory benefits, sleep appears to have an emotional cleansing benefit. Time spent asleep, particularly during REM sleep, provides an "overnight therapy" benefit not otherwise found in non-dream sleep and/or lack of sleep. REM sleep allows individuals to remove the emotional content from memories, taking the emotional edge off otherwise painful memories and/or stressful experiences. It can then be said that it's not time that heals all wounds, but time during sleep. Furthermore, this time spent sleeping is shown to be dependent on REM sleep dreaming specifically about the experience being processed. Likened to an internal car wash, REM sleep acts as neurological sanitization. Although chronically impaired sleep may exacerbate or result in early onset of psychiatric conditions (PTSD, anxiety, depression), it may also be just the thing needed to reduce the impact and/or adjunct effective treatment. The task then lies in adopting behaviors and easy to implement sleep strategies to reap the benefits. 

Sleep and Disease Prevention

Chronically poor sleeping patterns (less than 7 hours per night) have shown heightened levels of beta amalyoid and TAO, macrophage disruptions and altered gene expression. All as a result of poor sleep. Unfortunately, not only are hundreds of beneficial genes being down regulated, hundreds of negative are being up regulated. Further impaired sleep (less than 6 hours per night) results in higher risk of developing the toxic protein directly linked to both dementia and Alzheimers. Lastly, poor sleep increases insulin resistance, resulting in increased likelihood of developing diabetes. This ultimately acts as a catalyst for metabolic dysfunction in addition to the previous mentioned diseases.

Fortunately, we have an actionable solution .. sleep! As Dr. Walker states, "sleep is sanitary salvation" due to the glymphatic system's cleaning effects of the previously mentioned beta amalyoid and other waste products responsible for disease progression. When our brain and body are in cooperations, we can regenerate, recharge and enhance. This is shown by increase natural killers cell expression, insulin sensitivity and cognitive functioning. Successfully treating sleep disturbance may delay age related disease occurrence and improve cognitive function in those who've already developed these diseases. 

Sleep Debt & Sleep Banking

Although taking naps may beneficial in short term, they can be a double edged sword. Naps act as a sleep pressure valve, removing sleep causing adenosine for later in the evening when sleep is required. For this reason, it is often advised to resist temptation to alter one's sleep regularity by napping to prevent disrupting future night's sleep. If highly preferred or needed, keep naps 15-20 minutes in length to avoid deep sleep.

An alternative, proactive approach is to implement the "sleep banking" technique. This requires one to intentionally increase sleep quantity, whether through one or multiple bought of sleep, ahead of an oncoming known period of poor sleep quality. Whether a practical strategy to ensure quality sleep ahead of increased physical and/or psychological demand or a biological loop hole, sleep banking is an easy to adopt tool to bolster resilience. 

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QQRT (Quantity, Quality, Regularity, Timing)

• Quantity: The average adult needs between 7-9 hours of sleep per night.
• Quality: Equivalent to sleep efficiency (fragmented vs. continuous sleep). 
  
  • Another aspect of quality is the volume of deep sleep and sleep architecture
• Regularity: Sleeping and waking at the same time +/- 30 minutes. The most important variable that will train the circadian clock leading to improvements in both quantity and quality. 
• Timing: Align your sleep pattern with your chronotype (dependent on genetic - 9 different genes) 
  • 25-30% of people are night owls, 25-30% are larks, the remaining fall in between

Sleep Tech: Friend or Foe?

Wearable sleep tracking devices have gained popularity over the recent years and for good reason. Accurate data tracking tools allow one to make informed behavioral changes. One in particular, the Oura ring, has been shown to have high validity relative to competitors and is relatively easy to use. However, a cautionary message to those who are inclined to meticulously track each aspect of wellness. Although wearables and other health tech tools are best used to supplement behavior based interventions, this too can be an unnecessary pressure to adhere to a standard that unintentionally impairs, rather than improves, sleep quality. Due to the prevalence of this occurrence, the term orthosomnia has been given to those who develop an unhealthy obsession with perfect sleep, ultimately leading to poorer quality sleep. 

Other Considerations

Caffeine 

Caffeine's ability to maintain alertness is due to its adenosine receptor blocking activity. In doing so, the progressive sleep pressure due to increased adenosine molecules do not have a their intended effect. The build up of adenosine is inevitably felt when caffeine no longer blocks these receptors. Caffeine effects are felt long after consumption, with a half life of 5-6 hours and quarter like up to 12 hours. Individuals vary in caffeine clearing rate, dependent on the enzyme cytochrome p450-182. A practical approach is to limit caffeine use to the morning hours. A sophisticated approach is incorporating caffeine 90 - 120 minutes post waking, allowing a majority the remaining adenosine to bind to receptors prior to blocking them. This reduces the inevitable adenosine build up and sleep pressure in an easy to adopt daily approach. You will likely find a reduced afternoon crash as a result. 

Alcohol

It's not uncommon to drink alcohol in the evenings, if choosing to consume alcohol. Often times it is self reported that one's sleep is enhanced as a result. However, the decreased sleep latency is a sedative byproduct of alcohol consumption further resulting in decreased quality and REM sleep. Unfortunately, the threshold for sleep quality reduction is minimal with little alcohol consumption showing impaired sleep quality regardless of amount and/or time of consumption. The (unfortunate) reality is that no amount of alcohol is either healthy nor acceptable when minimizing its negative effects on sleep. 

THC & CBD 

THC impairs REM sleep, can lead to withdrawal sleep insomnia and REM/dream rebound. CBD has shown mixed effects, however is relatively unregulated. Has shown wakefulness promoting effects at lower doses and sleep promoting effects at higher dosages. The potential benefits at this time appear to be the anxiolytic effects, indirectly removing a primary barrier to sleep for many people leading to reduced sleep latency. Interestingly, there also appears to be hypothermic effects further promoting sleep. It is important to once again differentiate between sedation and sleep. The former is non restorative in many of the most crucial restorative effects of sleep. 

 

Supplement Your Sleep:

Supplemental tools should be viewed just as that, supplemental tools. Both magnesium and l-theanine are among the more commonly used natural sleep enhancing agents and have been shown to improve sleep quality with little to no known side effects. Alternatively, sleep aids (melatonin, ambien, etc), likely elicit sedation rather than sleep. It is for that reason that pharmaceutical aid should be taken with serious precaution and only under medical supervision. 

Chronotype Test

Good to Great

Taking professional athletes as a physical gold standard for human performance, we can extrapolate keys metrics necessary for improvements. It is estimated that 20-40% of athletes have undiagnosed disordered sleeping. Additionally, a staggering 80% of sleep disorders go undiagnosed. Minimal effort sleep extension strategies are often easy to implement provided you have the necessary baseline education. In fact, sleep education alone has shown to result in a 20-90 minute increase in total sleep duration. This further suggests that actionable strategies are dependent on easily digestible information.

Sleep plays a vital role in female hormonal balance. Estrogen, progesterone and follicle stimulating hormone (FSH), important aspects for menstrual cycle stability and reproductive health, is regulated through sufficient sleep. The previously mentioned emotional components of sufficient sleep are directly effected through hormone balance as well. The resulting emotional stability can help mitigate conditions such as premenstrual dysphoric disorder (PMDD). Men also are impacted by the negative effects of chronically poor sleep hygiene, none are likely more alarming (and more action inducing) than the effects on male testosterone levels. Men who slept 4 hours per night were shown to have testosterone levels of someone 10 years their elder. The resulting low levels have numerous metabolic, anatomical and cognitive health effects on men.  

Poor food selection from sugary, carbohydrate dense foods. Altered leptin, ghrelin and cortisol levels. Increase muscle loss relative to fat loss in individuals dieting during times of sleep restriction. Increased blood glucose levels, mimicking those of a type II diabetic after just 1 week of sleep deprivation. There exists a bidirectional relationship between sleep, food and diet including timing of food intake before desire time to fall asleep. Additionally, those will chronically poor sleep while dieting are shown to lose relatively more muscle mass rather than fat mass (the opposite of dietary intervention's intended purpose). Often, it is the practical approach, allowing one to sleep without impairing quality that will yield the best results. For this reason, neither going to bed on empty stomach (and therefore being hungry) nor eating (primarily higher starch) immediately before bed is recommended. 

Practice (+ Sleep) = Perfect

Lack of sleep has been showing to impair peak performance and recovery through various performance based metrics including respiratory function, maximal strength/power output and total time to exhaustion. Additionally, multiple studies have shown injury risk increases as a result of poor sleep. Exercise has been shown to improve both the structural and physiological quality of sleep. This suggests that appropriate levels of exercise act as a sleep enhancement mechanism which then acts as a performance enhancing mechanism. Although this effect is apparent regardless of time of exercise, it is recommended to avoid later evening exercise to prevent the endogenous chemicals and increased body temperature components of exercise and their effects on energy and wakefulness. Sleep enhanced motor function has been repeatedly shown as a result of deliberate practice followed by consistent quality sleep. 

Building A Sleep Sanctuary

Now that we have a general overview of multiple aspects of sleep hygeine and the numerous positive health effects of a consistent, quality sleep, how do we easily apply in a minimal effort way? Some easily applied recommendations to enhance your sleep quality are listed below: 

The above provides guidelines to create an ideal sleep environment to maximize the likelihood of getting a quality night's sleep. By following the Ideal Morning Routine, primarily focused on getting to bed and waking at the same time each day, you set the foundation for the night ahead. A cool room allows the body's core temperature to decrease the necessary 1 degree Celsius (2-3 Fahrenheit). By removing sleep disrupting lights (cell phone, tv etc), you reduce the likelihood of impairing the internal chemical process responsible for the appropriate sleep wake cycle. A previously mentioned cautionary message is to avoid the unnecessary stress of trying to perfect your sleep. Every health tool is ultimately meant to improve your quality of life. By implementing as many of the above as you can, as frequently as you can, you move the needle in the right direct...one great night sleep at a time! 

 

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