Sleep good if you wish to live 125 years and beyond

We are discussing Dr Shahid's Six Principles of health. We have already discussed the First two principles in detail. We have also discussed the first part (Rest) of the Third Principle (Rest, Sleep anf Entertainment, RSE). The next we are going to talk about sleep

SLEEP

Sleep like many other mysteries in human behaviour, is the least understood phenomenon. We really don't know why we need to sleep. Nevertheless, we are certain about one thing that we all need to sleep. Humans physical, mental & spiritual health depends of certain hours of sleep daily. It is also necessary for survival. Without sleep individual will not last long.

Sleep is the state of natural rest in humans & many animals. It is characterized bya reduction in voluntary body movements, decreased reaction to external stimuli, an increased rate of anabolism ( synthesis of body tissue ) & a decreased rate of catabolism ( break down of body tissue ). Even though sleep is a form of unconsciousness, technically it is much different from it.

Optimal sleep amounts to 8 hours in 24 hours. However, a life span study of sleep amount shows that those who sleep 4 - 7 hours live the longest, with those sleeping less than 4 or more than 9 hours living shorter lives. Incidentally it only applies to adult. Children need much longer sleep depending on their age.

A good night sleep does wonders. It

i, Improves performance in test
ii, Reduces risk of accidents
iii, Increases immune system
iv, Sharpens memory
v, creates a general sense of well being

Researchers from the University of Warwick and University College London have found that lack of sleep can more than double the risk of death from cardiovascular disease, but that too much sleep can also double the risk of death. “Short sleep has been shown to be a risk factor for weight gain, hypertension and Type 2 diabetes sometimes leading to mortality but in contrast to the short sleep-mortality association it appears that no potential mechanisms by which long sleep could be associated with increased mortality have yet been investigated. Some candidate causes for this include depression, low socioeconomic status and cancer-related fatigue.

Stages of sleep :

There are 4 stages of sleep.

First stage is characterized by disappearance of alpha waves seen in awake state & appearance of beta waves on EEG. This stage is sometimes referred to as somnolence or drowsy sleep. During this stage the subject loses some muscle tone & conscious awareness of surrounding, develops some muscle twitches & occasionally hynogogic hallucination. This stage is gateway between wake & sleep. This stage lasts for few minutes. Subject can be awakened very easily during this stage

Second Stage results in complete disappearance of conscious awareness. This occupies 45-55% of sleep. One can be awakened easily at this stage also.

Third stage is also known as REM (rapid eye movements) sleep. During his stage dreaming takes place. This occupies about 10 - 30% of total sleep. Dreaming is extremely essential for psychological well being. Deprivation of this stage results in icreased irritibility,anger & all kind negative emotions. Continued loss of dreaming (REM deprivation) for 4-5 days cause hallucinations & psychosis. Sleeping pills & alcohol diminish this stage.

Fourth stage is the stage of deep sleep. Also known as NREM (Non rapid eye movements) stage. During this stage subject is very difficult to be awakened. Night terrors ( bad & fightening dreams ), bed wetting & sleep walking take place during this stage. It occupies 10-15% of total sleep. This stage can be labelled as the restorative stage of physical fatigue. Anabolic activity ( i.e. physiological process of growh & rejuvination of organism's immune, nervous & musculoskeletal system ) is marked in this stage.

Functions of Sleep :

The multiple theories proposed to explain the function of sleep reflect the as yet incomplete understanding of the subject.

It is likely that sleep evolved to fulfill some primeval function, but has taken over multiple functions over time as organisms have evolved. Some of the many proposed functions of sleep are as follows:

A. Restoration

i. Wound healing has been shown to be affected by sleep. At least one study shows sleep deprivation hindering the healing of burns on rats.

ii. Immune System. It has also been shown that sleep deprivation affects the immune system. There is clear reduction in WBCs in individual who don't sleep enough

iii. Growth hormones. Some studies show that sleep reduction affects somatic growth by reducing the level of growth hormone.

iv. Metabolic rate. Overall metabolic rate goes down during sleep and certain anabolic hormones such as growth hormones as mentioned above are secreted preferentially during sleep. Sleep among species is, in general, inversely related to the animal size and basal metabolic rate. Small animals and birds with a very high basal metabolic rate sleep for up to 14 hours a day whereas elephants and giraffes with lower BMRs sleep only 3-4 hours per day.

v. Energy conservation could as well have been accomplished by resting quiescent without shutting off the organism from the environment, potentially a dangerous situation. A sedentary non-sleeping animal is more likely to survive predators, while still preserving energy. Sleep, therefore, does something else other than conserving energy. Most interestingly, hibernating animals that wake up from hibernation go into rebound sleep because of lack of sleep during the hibernation period. They are definitely well rested and are conserving energy during hibernation, but need sleep for something else. Rats kept awake indefinitely start dying after a few days.

B. Anabolic/catabolic

Non-REM sleep may be an anabolic state marked by physiological processes of growth and rejuvenation of the organism's immune, nervous, muscular, and skeletal systems. Wakefulness may perhaps be viewed as a cyclical, temporary, hyperactive catabolic state during which the organism acquires nourishment and procreates.

C. Ontogenesis

According to the ontogenetic hypothesis of REM sleep, the activity occurring during neonatal REM sleep (or active sleep) seems to be particularly important to the developing organism. Studies investigating the effects of deprivation of active sleep have shown that deprivation early in life can result in behavioral problems, permanent sleep disruption, decreased brain mass, and an abnormal amount of neuronal cell death.

REM sleep appears to be important for development of the brain. REM sleep occupies majority of time of sleep of infants, which spend most of their time sleeping. Among different species, the more immature the baby is born, the more time it spends in REM sleep. Proponents also suggest that REM-induced muscle inhibition in the presence of brain activation exists to allow for brain development by activating the synapses yet without any motor consequences which may get the infant in trouble. Additionally, REM deprivation results in developmental abnormalities later in life.

However, this does not explain why older adults still need REM sleep, and why the fraction of time spent does not change significantly as one ages. Aquatic mammal infants do not have REM sleep.

D. Memory processing :

Scientists have shown numerous ways in which sleep is related to memory. In a study conducted recently showed that working memory was affected by sleep deprivation. Working memory is important because it keeps information active for further processing and supports higher-level cognitive functions such as decision making, reasoning, and episodic memory.

All the different studies suggest that there is a correlation between sleep and the many complex functions of memory.

E. The "Preservation and Protection" :

This theory holds that sleep serves an adaptive function. It protects the person during that portion of the 24-hour day in which being awake, and hence roaming around, would place the individual at greatest risk. Organisms do not require 24 hours to feed themselves and meet other necessities. From this perspective of adaptation, organisms are safer by staying out of harm's way where potentially they could be prey to other, stronger organisms. They sleep at times that maximize their safety, given their physical capacities and their habitats.

However, this theory fails to explain why the brain disengages from the external environment during normal sleep. Another argument against the theory is that sleep is not simply a passive consequence of removing the animal from the environment, but is a "drive": animals alter their behaviors in order to obtain sleep. Therefore, circadian regulation is more than sufficient to explain periods of activity and quiescence that are adaptive to an organism, but the more peculiar specializations of sleep probably serve different and unknown functions.

Moreover, the preservation theory does not explain why carnivores like lions, which are on top of the food chain, sleep the most. By the preservation logic, these top carnivores should not need any sleep at all. Preservation does not explain why aquatic mammals sleep while moving. Lethargy during these vulnerable hours would do the same, and will be more advantageous because the animal will be quiescent but still be able to respond to environmental challenges like predators etc. Sleep rebound that occurs after a sleepless night will be maladaptive, but still occurs for a reason. For example, a zebra falling asleep the day after it spent the sleeping time running from a lion is more and not less vulnerable to predation.

next we will discuss effect of food and drinks on Sleep.

For comments and question please write to :

syedshahidmd@yahoo.com.au