What is sleep, how sleep affects an individual’s life style and what happens when things go wrong? in order to understand these questions, it easier if we can elaborate and address (i) the stages of how a person falls asleep, (ii) what regulates our sleep and the qualitative difference it brings, and lastly (iii) type of sleep disorders and risk factors which bring it. It is true to say that anything living needs a resting. Like all animals at sleepto rest even plants ceases photosynthesis activities. Generally, human’s become active with the sunrise and start to get tired and sleep with the sunset. These activities in humans are mainly governed by different types of neurotransmitters produced by the brain to keep us awake such as serotonin, norepinephrine and to sleep such as orexin, GABA.
WHAT IS SLEEP?
The Stages Of How A Person Falls Asleep.
There are five stages to sleep; from stage 1 to 4 and REM (rapid eye movement).
This is the first stage which could last for about 10-20 minutes. Person could be easily awakened. Eye movement and muscle activities are slow at stage 01.
Following stage 01 starts stage 02 of the sleep. Brain waves become slower and eye movements stops. As shown on figure 01, there could be sleep spindles (rapid waves) at intervals.
Stage 03 and Stage 04:
Individual is very difficult to awake at these stages. Brain waves slows down significantly. Delta waves starts to appears at stage 03 with smaller, faster waves which progress into almost exclusively delta waves at stage 04. There will be no eye movement or muscle activities at these stages.
If awaken, individual find it difficult to adjust for the reality. Bedwetting, night terrors and sleep walking occurs in stage 04.
Stage 05 or REM sleep:
REM (rapid eye movement) sleep is when a person starts to breath rapidly. Additionally, the eye movements are rapid and in different directions. Heart rate increases and males have penile erection at REM stage. Limb muscles are temporarily paralyzed.
Figure 01: Show the stages of sleep from stage 01 where an individual is awaken easily to REM. Clinical study done with polysomnography shows the muscle movements (electromyo-gram - EMG), the brain (electroencephalogram - EEG), and eye movement (electrooculogram - EOG).The significant difference is on EEG and EOG waves as shown.
HOW SLEEP AFFECTS LIVING BEINGS: What Regulates Our Sleep & The Qualitative Difference It Brings.
The two components that regulate our sleep in our body is hypothalamus (in the brain) and circadian (suprachiamatic nucleus). Neurotransmitters involves in our sleep are histamine, dopamine, norepinephrine, serotonin, glutamate, orexin and acetycholine. Previously it was thought that sleep is a mode where body is resting and the brain activity is less. However, sleep studies showed contrasting results. They showed that sleep is a very important part of living things. During sleep the brain activity is very high, as brain replenish glycogen levels, retain information for better memory, restore/ rejuvenate to grow muscles, repair tissues and synthesize hormones.
THINGS GO WRONG: Type Of Sleep Disorders & Risk Factors.
National Institute of Neurological Disorders and Stroke states that about 40 million people in United States is diagnose with a chronic long-term sleep disorder. There are about 70 different sleep disorder, which are mainly divided into three;
(i) Dyssomnias; sleep disorders with hypersomnia or insomnia. This type is a primary neurological condition where excessive daytime sleepiness occurs. As a result person may suffers from falling asleep spontaneous and unwillingly at inappropriate times,
(ii) Parasomnias; for instance, bedwetting, Bruxism (tooth grinding), sleep sex (sexsomina), where unnatural movements, emotions, and other abnormalities linked with sleep. As a result sudden/ transient loss of muscle tone while awake. It could lead to sudden cease of a motor neuron that can result a person to collapse to the floor.
(iii) Circadian rhythm sleep disorders; involving the timing of sleeping. Other minor disorder categories are medical or psychiatric conditions (example; alcoholism, anxiety disorder), and sleeping sickness cause due to parasitic infections such as Tsetse fly.
The above categories of disorder arise from different causes. Evidence shows that 58% of youth in United States suffer sleep disorders due to traumatic childhood experience such as sexual abuse and/or family conflict happened between (not limited to) age 7-15 years old. Others may be due to family history where a first degree relative suffer from same sleep disorder or traumatic brain injury result in obstructive sleep apnea.