Medical Bits – Vol 1.6: Your Health – Sleep
Why do humans, mammals, and most other living creatures need to sleep? Why do we become irritable due to lack of sleep?
We do not know why sleep is essential for life, but we do know that the mesencephalic ascending reticular activating system in the lower region of the brain is responsible for vigil and its reduced activity leads to sleep. We have an internal clock that is responsible for our circadian rhythm driven by a complex neurochemical system that receives information from the environment and interacts with our multiple neuroendocrine systems to drive our sleep-wake balance and homeostasis.
Sleep is a highly conserved behavior across species and universally present in mammals that is essential for life. Total sleep deprivation in humans over 2-3 weeks leads to impaired thermal regulation, energy balance, and immune function eventually causing death. Predatory species like HUMANS can enjoy long, uninterrupted sleep that usually has a circadian rhythm. We procure energy sources, take care of our progeny, mate and take care of life’s necessities usually during the daytime and sleep at night. Other more vulnerable species have adapted by sleeping short intervals (to avoid becoming the lunch of predators) and a few such as seals and dolphins can switch off/on their sleep between brain hemispheres, such that one rests as the other one maintains vigil!
The pattern of continuous, nocturnal sleep has been most prevalent since the late 1900’s driven to a large degree by modernity and electricity. In nomadic tribes and pre-modern civilizations, humans had more frequent and shorter periods of sleep. It’s interesting to note that the “siesta” habit has been associated with an almost 40% reduction in coronary mortality, perhaps due to lower cardiovascular stress! Also, mild evening exercise improves sleep, cognitive tasks, and mental health in the elderly!
Most people sleep on average 7.5 hours per night, but there is a normal distribution +/- 1.5 hours. Aging is associated with a decline in the amount of required sleep and is associated with more frequent arousals and difficulty in maintaining sleep. By age 75, there may be a complete loss of “deep sleep”. What is this?
We have known about different “stages” of sleep since 1929, when the psychiatrist Hans Berger recorded cortical electrical potentials and termed those recordings electroencephalograms (EEGs). In the 1950’s we learned about REM (Rapid Eye Movement) sleep.
In adults, sleep is initiated through Non-REM sleep and episodes of REM sleep occur in approximately 90-minute intervals throughout the night. This cycle is repeated 3-6 times with rising duration of REM sleep as the night progresses, and this pattern is established by age 5. There are several important alterations of sleep leading to disruptions in this reparative process. The most common, of course, is insomnia, which is the dissatisfaction with the duration or quality of sleep. Others include the increasingly prevalent Obstructive Sleep Apnea syndrome (OSA), Central Sleep Apnea, hypoventilation syndromes, narcolepsy, periodic limb movement disorders, restless leg syndrome, circadian rhythm disorders, and others. Fatal Familial Insomnia (FFI) is an extremely rare genetic condition that illustrates the importance of sleep. Patients with FFI increasingly develop insomnia until they stop sleeping altogether, before dying of the disease.
OSA is one of the most common sleep disorders affecting up to 20% of the adult male population and 8% of females. Increasing weight and a predisposing airway anatomy may lead to this problem, which often leads to multiple negative metabolic and cardiovascular complications, such as metabolic dysregulation, insulin resistance, glucose intolerance, imbalance in appetite hormones, hypertension, pulmonary hypertension, and more.
It is always important to review medical conditions that can aggravate or lead to sleep disorders. It is equally important to review medications that may worsen these conditions or sometimes be responsible for them.
I encourage you to read more about proper sleep hygiene here: https://www.sleepfoundation.org/articles/sleep-hygiene and also to review your sleep with me during the course of your annual exam such that we are both “awake” and alert in our preventive quest to keep you healthy!
Means we use must be as pure as the ends we seek.
You all know that hypertension is a major preventable risk factor for vascular disease, congestive heart failure, strokes and kidney disease. In 2017 American College of Cardiology (ACC) and American Heart Association (AHA) updated their recommendations and lowered the definition of hypertension to 130/80 mm Hg or higher, increasing the number of adults with hypertension from 31.9% to 45.6%! As we age, our blood pressure naturally rises since the elasticity of our vascular system (along with the elasticity of all tissues) declines. Several consequences ensue, but one of the most common and associated with significant morbidity and complications is the development of “diastolic” dysfunction heart failure which is a fancy term to indicate that the heart chambers and the pump operate at high pressures, resulting in elevated atrial pressures. Over time, dilatation of the heart chambers may cause arrhythmias, such as atrial fibrillation and atrial flutter. Another consequence is the rise in pulmonary capillary pressures when we exercise or increase vascular demands, which may lead to worsening breathlessness with exertion. A good summary can be found here:https://www.mdedge.com/ccjm/article/191816/cardiology/hypertension-guidelines-treat-patients-not-numbers Please, make an effort in controlling your salt intake, exercise daily, and keep your blood pressure under control!
Debunking Myths: Q&A
Vaccines may cause autism!
Myth! Multiple studies have been conducted and there is conclusive evidence that vaccines do NOT cause autism. If interested in further reading, this Center for Diseases Control (CDC) reviews the literature here: https://www.cdc.gov/vaccinesafety/concerns/autism.html and this study was conclusive: https://www.jpeds.com/article/S0022-3476(13)00144-3/pdf?ext=.pdf
I have an egg-allergy. Therefore, I should not get the influenza vaccine!
Myth! Influenza vaccine manufacturing has been purified to such levels that the glycoprotein administered to induce immunity is highly purified and unlikely to cause allergic reactions. There may be local redness and inflammation, which usually indicates that the vaccine has triggered a good immunogenic response with consequent inflammatory reaction, but it does not mean that you have an “allergy.” For those exceptional individuals who have had an anaphylactic reaction to influenza vaccines in the past, the recommendation is to proceed with vaccination in a doctor’s office or medical facility. You may also consider the new Flublok vaccine, which has been developed using recombinant technology and does not have any egg protein or components.
Cell phones cause brain cancer!
Myth! This issue has received significant attention and is currently under investigation by the World Health Organization and the International Agency for Research on Cancer. Electromagnetic radiation may have a very tiny effect in the development of gliomas, a benign form of brain tumors, but the research has been inconclusive and the rise in risk extremely small. The issue continues to be monitored closely by international agencies.
We will address additional medical “myths” in future communications. In the meantime, keep cool, eat a nutritious and diverse diet, stay active, and be happy! The only fountain of youth proven by science, experience, and millennia are exercise, laughter, humor and a good positive attitude!
Enjoy every minute of the JOURNEY! Please, feel free to share any questions you may have, to address privately or as part of future newsletters!