5 Hacks for Better Sleep
Sleep is essential for good health. It is a well established fact that chronic sleep deprivation can lead to immune system disfunction, chronic disease conditions like diabetes, obesity, high blood pressure, depression, anxiety, and even death. Yet, many of us (one out of three Americans, in fact) tend to put little emphasis on sleep. According to data published by the CDC, sleep problems, whether in the form of medical disorders or related to work schedules or a fast-paced, high-pressure lifestyle, are pervasive in our modern society. (1)
Sleep and Your Immune System
When you sleep your immune system releases proteins called cytokines, some of which actually help to promote sleep. These cytokines assist your body in overcoming infections as well as recovering from stress. Sleep deprivation may decrease production of these protective cytokines.
Additionally, nocturnal sleep, especially slow wave sleep or deep sleep, prevalent early in the night, promotes the release of growth hormone and prolactin, while anti-inflammatory actions of cortisol and catecholamines (epinephrine and norepinephrine) are at their lowest levels. This endocrine milieu during early sleep supports the proper functioning of the adaptive immune system by promoting the interaction between antigen presenting cells and T cells, and the formation of long-lasting immunological memories. This helps the body create a more robust defense against infectious organisms like viruses and bacteria.(2), (3)
In a fascinating book I recently read, Why We Sleep, Unlocking The Power of Sleep and Dreams, the author, Mathew Walker, says that consistently failing to get six or seven hours of sleep considerably weakens your immune system and increases one's risk of cancer, high blood pressure, coronary artery plaque accumulation and blockage due to an increased production of reactive oxygen species (ROS).
Rest and Recovery
During a regular night's sleep, you go through several 90-minute cycles consisting of four distinct phases. Each of those phases plays an essential role in maintaining your mental and physical health. Sleep optimizes our learning capacity and memory as well as our emotional composure. Have you noticed how weepy and on edge you feel after a sleepless night?
The four stages of the sleep cycle can be divided into two main categories: non-rapid eye movement (NREM) and rapid eye movement (REM). During NREM and REM sleep your eyes are either still or moving rapidly as "your brain progresses sequentially through each stage: wake, light sleep, deep sleep, rapid eye movement (REM), and repeat."(4)
NREM Sleep
NREM sleep happens mostly in the early stages of the night (typically between the hours of 10 PM and 2 AM). This phase includes the periods of wakefulness, light sleep and deep sleep. Deep sleep is the most restorative type of sleep, promoting muscle growth and repair as well as waste removal in your brain. (4)
Deep sleep is characterized by slow brain waves, lower heart rate and blood pressure, and an increased blood flow to muscles. In other words, we need deep sleep for proper rest and recovery. Now you see why it is important to go to sleep before 10 PM and not cut short this stage of your sleep cycle. If you do, you wake up feeling groggy, cranky and sore.
REM Sleep
REM sleep is characterized by rapid eye movement and extreme brain activity. REM sleep typically happens in the second half of the night or in the later stages of the sleep cycle. When you don't get enough sleep or wake up very early, you do not allow your brain to properly consolidate and convert memories from short to long-term and move them from the hippocampus to the cortex. Moreover, lack of sleep prevents our brain from strengthening its neural connections, which can lead to numerous mental, physical, and emotional problems.
REM sleep is essential to re-energizing your mind and is associated with dreaming, memory consolidation, learning, and problem solving. (4)
Looking at the figure below, you can roughly estimate how long each stage of the sleep cycle should last depending on how many hours of sleep you get. This of course will vary based on your daily habits, diet, stress and exercise level as well as on your body's ability to rest and recover.
Tools for Optimizing Sleep Quality
The quality of your sleep can be disrupted by so many factors. I find that tracking my sleep cycle as well as heart rate variability, and recovery index helps me make better choices throughout the day.
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