by Ihor Magun, MD, FACP
Sleep is an integral part of our life and well-being. It is also quite interesting and complex, and serves many vital roles in our energy level, mood, appetite, and even libido. For optimal health, it is medically proven that adults need at least seven hours of sleep. Children need even more. Cutting down the time we allocate for sleep can have potential consequences affecting our health.
Sleep literally provides a break from our daily activities. But despite all the advances in science, the reason we sleep is actually not fully understood. What we do know is that sleep occurs in stages.
Stage one is the lightest stage, where our muscles begin to relax, accompanied by a slowing-down of our breathing and heart rate. Simultaneously, our brain waves shift to a sleeping stage. Thousands of neurons in our brain switch from a walking to a sleeping state. Melatonin is released to help induce this process.
Stage two - the body continues to relax.
Stage three is referred to as deep sleep, when blood pressure as well as heart rate reach their lowest point, allowing these organs to literally "have a rest." The sympathetic nervous system relaxes. This is our "fight or flight" response mechanism. It is important, since lack of sleep increases our sympathetic nervous system, which leads to high blood pressure and an increased risk of heart disease. Our level of cortisol, commonly referred to as the "stress hormone," is decreased. Growth hormone is also released with different functions. It can affect our height when we are growing, but in later stages in life it helps in body repair. Growth hormone declines progressively with aging. A substantial decrease in growth hormone with inadequate sleep has been lined to an increase in abdominal girth, commonly referred to as a fat gut.
Stage four - referred to as REM (Rapid Eye Movement) sleep - is manifested in an increase in heart rate and breathing with an acceleration of brain activity. It is the time when we dream. Our brain sorts and stores information in a consolidated way, actually creating long-term memory. During this time, our muscles are temporarily paralyzed, a condition referred to as atonia. It has been suggested by researches that this paralysis might be so no one can physically act out their dreams since they may be bizarre.
While sleeping, our immune system releases inflammation-fighting cytokines. Cytokines affect the growth of all blood cells and other cells that help the body's immune and inflammation response.
For individuals who do not experience nocturnal urinary issues, a hormone released under a circadian rhythm cycle referred to as an anti-diuretic hormone - vasopressin - prevents our need to urinate overnight. That is why we may not need to void for all hours we are asleep, something that does not occur during waking hours. With aging, the amount of this hormone released decreases, leading to awakening to void.
Our temperature can decrease by one to two degrees during the passage of sleep stages. It is suggested that this temperature drop increases the likelihood of sleep initiation and may facilitate our achieving a deeper stage of sleep.
Lack of sleep can influence two hormones: leptin and ghrelin. These hormones play a key role in how much we eat while awake.
Some advice for good sleep: maintain a regular sleeping schedule, allowing adequate time for sleep. Avoid triggers that interfere with sleep - medications, caffeine, excessive alcohol (which can actually disrupt sleep stages), and personal triggers that may keep your mind in a more active state. I sincerely hope you make an effort to get the reset you need for better physical and mental performance every day and over the long term.
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