The Importance of Sleep
Good sleep is necessary for a healthy and balanced life.
- Nearly all physiological and behavioural functions in humans occur on a rhythmical basis.
- Most adults need approx 8 hours for full restorative sleep, some cultures split this to 6 or 7 hours plus a 1 to 2 hour siesta. Although many people say they require less, scientists who study sleep find that only 10 % of the population fall into this category.
Recent studies show that chronic lack of sleep and sleep disorders may be a factor in the development of cardiovascular disease, obesity, diabetes and increases in stress.
Scientists believe sleep may be a way of recharging the brain.
It has a chance to shut down and repair neurons. (nerve cells). It can also exercise important neuronal connections that might otherwise deteriorate due to lack of activity.
Without sleep these neurons may become so depleted in energy or so polluted with by products of normal cellular activity that they begin to malfunction.
Too little sleep:
- leaves us drowsy and unable to concentrate the next day.
- leads to impaired memory, reduced physical performance and reduced ability to sort and calculate.
- also leads to mood swings and depression.
Studies have shown that loss of just 1 and 1/2 hours sleep can result in:
- a 32% reduction in daytime alertness.
- double the risk of sustaining an occupational injury.
- impairs the immune system, memory and cognitive ability (to think and process data)
Long term consequences of poor sleep can lead to:
- high blood pressure
- heart attack
- heart failure
- DROWSY DRIVING.
Obesity and lack of sleep.
Interestingly lack of good sleep can cause weight gain by increasing hunger and affecting the metabolism(more info with beauty section).
Sleep is a stage of unconsciousness where the brain is more responsive to internal than external stimuli. It is an active process that cycles at an ultradian rhythm of about 90 minutes. Normal sleep is divided into phases of REM (rapid eye movement) and NREM ( non rapid eye movement).
REM follows NREM and occurs approx 4 to 5 times during an 8 hour sleep. The first REM stage may be very short, 10 mins or less, while the last phase of REM can be over 60 mins. During NREM the heart rate reduces together with cardiac output and drop in blood pressure. REM , although more variable usually shows an increase in all of the above and this is when we dream.
Muscles are totally relaxed during the REM stage and this takes up 20 to 25 % of our total sleep. Hence importance of a good pillow to maintain posture etc.
REM rates of sleep are directly related to intellectual functioning so the more we get the better we function. REM levels are shown to be reduced in the elderly who sleep less and relax less and scientific trials have shown that during the sleep time, Alzheimer’ patients have less time in REM sleep than normal.
“Sleep is a time for the body and brain to shut down and rest.”
Sleep is an active process involving specific cues for it’s regulation, The body functions may slow slightly but some activity, such as delta waves in the brain increase. The endocrine system secretes certain hormones such as prolactin and growth hormone. In REM sleep many parts are as active as when awake.
“Getting one hour sleep less will not have an effect on my daytime functioning”
This sleep ‘debt’ builds up quickly and can have profound effects on daytime performance, thinking and mood.
“The body adjusts quickly to different sleep schedules”
The biological clock will work with day and night schedules even when you try to change it. Those who work night shifts still feel naturally sleepy when night time comes. This also occurs with jet lag. The conflict, set up by trying to be active during the brain’s biological night time can lead to decreased cognitive and motor skills. Shift workers with changeable hours usually start to suffer with a sleep debt. Those who are active every night need to retrain their biological clock with light cues.
“Adults need less sleep as they grow older”
Older people do not need less sleep, but they often get less. The ability to sleep for long periods and get into the deep rest full stages of sleep gets harder as we get older. The older we get the more ‘fragile ‘ our sleep and we are more easily disturbed by light, noise, and PAIN.