Sleep and Your Health

The average adult spends about one-third of their life sleeping or attempting to sleep. While this may seem like a large investment of time, the payoff is well worth it. Sleep impacts every major organ in the body, every physiological system, and every brain process. In fact, sleep plays such a critical role in overall health that insufficient sleep is even linked to lower life expectancy. The American Academy of Sleep Medicine recommends that adults sleep seven or more hours each night; however, more than one-third of adults do not obtain the recommended amount of sleep. This lack of sufficient sleep contributes to sleep-related deficiencies and diseases. 

The Role of Sleep in Brain Health 

Sleep plays an integral role in numerous aspects of your health and daily function, including processes of your brain. Your brain has a fixed amount of storage space, and this storage is managed while we are asleep. During sleep, unneeded neural connections are removed, making room for new connections to be built. This process is crucial for short-term memories to be converted to long-term memory, and for long-term memory to be strengthened. Because of this, not surprisingly, insufficient sleep significantly impacts the ability to learn and retain information. Additionally, concentration, decision making, speed of processing information, and emotional calibration are all dependent on sleep. Without good sleep, the ability to concentrate and make logical decisions is impaired, processing speed is reduced, and both positive and negative emotional swings are more likely. Poor sleep is also associated with magnified mental health concerns, such as depression, anxiety, and suicide; increased rates of addiction, substance use, and risky behaviors; and behavioral problems, such as aggression and irrational thoughts. 

The Role of Sleep in Physical Health 

Sleep health is closely tied to physical health in many ways. First non-REM sleep is important for a myriad of physical repair and growth processes including tissue repair, building bone and muscle, and strengthening the immune system. Growth hormone is also released during deep NREM sleep, promoting this growth and repair during sleep. Non-REM sleep is crucial for optimal physical health. 

Poor sleep is associated with increased likelihood of poor diet choices including higher food intake, higher daily caloric intake, and higher likelihood of choosing unhealthy food choices such as high-carb and high-sugar foods. Poor sleep is also associated with negative metabolic health outcomes, such as glucose spikes (high blood sugar levels) and type II diabetes. Poor sleep may also contribute to obesity. 

Poor sleep is also linked to an increased risk for poor cardiovascular health outcomes including hypertension (high blood pressure), heart disease, and stroke. 

Sleep and Normal Aging 

Disordered sleep becomes more common as we age. The areas of the brain most affected by aging are the same ones associated with generating deep sleep. In other words, the areas of our brain that deteriorate as we age also means we end up losing deep sleep. As a result, there are three notable changes to sleep as we age: 

1. The quantity and quality of sleep, especially non-rapid eye movement (NREM) sleep, is reduced. 
2. The efficiency of sleep is reduced, meaning more time is spent awake in bed trying to fall asleep and/or there are more times waking up throughout the night, fragmenting sleep.
3. The typical timing of sleep is disrupted, due to changes in the circadian rhythm, resulting in earlier desired bedtimes and wake times.

These changes are effects of natural aging, and unfortunately, mean that seniors often experience the effects of poor sleep, including worsened memory and emotional changes, which are often mistaken for dementia.

Sleep and Alzheimer’s Disease

Sleep is also closely linked to Alzheimer’s Disease (AD). Normal aging reduces sleep quality, affecting memory. AD worsens this. AD is associated with the buildup of beta-amyloid plaques, which are clumps of toxic protein that kill surrounding brain cells. These plaques affect the same regions of the brain associated with deep NREM sleep, meaning that the greater the plaque buildup, the more sleep is disrupted. However, amyloid plaques do not affect the memory-related hippocampus, raising the question: how does amyloid cause the memory loss seen in AD? It turns out that amyloid disrupts areas of the brain associated with deep NREM sleep, which causes disruption of sleep, and in turn results in the memory impairment seen in AD. Simply put, sleep is the missing link between amyloid plaques and memory dysfunction in AD. To make matters worse, deep NREM sleep clears toxins like amyloid, but disrupted sleep hinders this, leading to a cycle: more amyloid, less sleep, more buildup. Although getting too little sleep across the adult lifespan significantly raises risk for AD, research also supports that treating disrupted sleep can reduce the risk of AD. 

Recommendations to Optimize your Sleep 

Getting sufficient sleep is important to optimize your overall health and longevity. Here are some evidence-based tips to optimize your sleep: 

• Stick to a schedule. Try to have the same bedtime and wake time every day, including on the weekends. 
• Limit caffeine intake to 8-10 hours before bedtime. 
• If you nap, avoid doing so after 3pm. 
• Limit technology use to at least one hour before bed. 
• Create a dark and cool sleeping environment.
• Avoid eating a large meal before bedtime. 
• Exercise at least 2-3 hours before bedtime. 
• Avoid alcohol. If you consume alcohol, lengthen the time between consumption and bedtime. 
• View early morning sunlight. If you are an older adult wanting to delay bedtime by a couple of hours, wear sunglasses in the morning for less early sunlight and expose yourself to more afternoon sunlight.