Sleep and how we dream

Sleep and how we dream

Every creature on Earth reacts instinctively to the patterns of day and night, light and darkness. Some animals such as Bats, night means activity and daylight means sleep. Generally mammals tend to be light lovers and sleep at night, extreme fatigue and danger can cause the pattern to alter occasionally.

Newborns have to acquire the 24 hour rhythm and over time will the child will become accustom to their parents sleep patten and adjustments to the 24 hour cycle regulates the growing child’s sleep pattern. Once acquired, the daily or circadian rhythm remains with us until until we pass.

As with all functions learned, this is stored in the cerebral cortex (the grey matter) of the brain.

Our always ticking, biological clock needs more than the cerebral cortex, it also uses another part of the brain called hypothalamus which regulates the body temperature. Our body temperature falls from its normal 37℃ to as low as 35.5℃ in the early hours of the morning. Moments of acute sweating through the night are normally associated with illness or sever sleep disturbances. At noon our temperature may rise to more than 37℃, this is the time when most people achieve optimum efficiency both physically and mentally. Approximately two hours later a sudden change  in the biological clock will mark the onset of the post-lunch dip and happens whether or not lunch has been eaten.

The hypothalamus also regulates the flow of chemicals in the blood and urine. Normal sleepers will find they can drink a fair amount of fluid before sleeping and sleep through without visiting the bathroom. The production of urine depletes at the onset of sleep. Poor sleepers or those of you with medical problems will wake often to relieve themselves. The body can adjust to a reversal of its learned cycle over a period of time as shift workers will tell you but, repeatedly scrambling the body’s  biological rhythm is harmful.

Apparently when we are asleep we are deaf and blind to the outside world, sleep is an activity. Seemingly we are unconscious yet on one level – the level of dreams – another level of consciousness operates vividly.

When experiencing nightmares, our dreaming consciousness can evoke extreme response propelling us into normal consciousness that we wake screaming.

As we lay snoring our bodies are being repaired. Body cells begin to divide faster than during wakefulness. Surges of growth hormone are released into the blood stream at our deepest sleep, repairing and renewing our bodies while our brainwaves are slow and long. Great sleepers can wake to find they their colds or ailments are gone due to the release of the growth hormone but Insomniacs or light sleepers don’t receive their full quoter of this invaluable hormone and are more prone to accident or illness (prolonged colds).

Crazy eye movements

When we fall asleep we initiate a complex serious of change in consciousness that succeeds each other throughout the night. There is no one uniform that we call sleep. The deepest sleep comes almost immediately after we fall asleep, followed by a period of lighter sleep, this is when our eyeballs go crazy beneath our closed eyelids.

This phase is called rapid eye movement (REM) when sleep is associated with dreaming. On average this happens 5 times a night during an 8 hours sleep pattern and generally wakening after the first one. People wakened during REM will briefly remember their dreams but shock of an alarm clock going off will probably instantly drive our dreams away.

Many people will say they never dream but through research it’s proven that everyone dreams. The EEG machine that used to measure our brain activity has established a sleep pattern we all conform to. As we become drowsy our brainwaves become longer and slower and eventually the delta waves of the deepest sleep. This is when our bodies go into shutting down our systems; digestive  processes  and the production of urine diminishes. The heart slows down, under closed the eyelids the pupils contract and our bodies require less oxygen to breath.

There are two forms of sleep Orthodox and Paradoxical

We start with Orthodox which is split into four phases, The first is accompanied by slower pulse and is a light sleep where the brainwaves slow down. A state that the smallest noise or street lamp can wake you. Second and third phase we enter a deeper state of relaxation and slower rate of breathing. Phase four we enter a deep sleep, the EEG records long slow delta waves proof of no mental activity taking place.

Approximately 90 minutes every night we enter the paradoxical sleep with rapid eye movement, increased heart rate and blood pressure and fast erratic brainwaves, a sudden agitation of mental activity. We are dreaming.

Some physical can mimic wakefulness, production of adrenalin during dreaming of danger or horror but during dreams of this phase our muscles are at their weakest, it’s like we are paralysed.

Physiological  dream is where physical activity or outside influences  are dramatised in our dreams e.g a telephone ringing could be dream alarm or a full bladder could turn into a dream of drowning. People who are highly active especially if its been dangerous, traumatic or mentally stretched require more paradoxical sleep. The soothing restoration of harmony that sleeping and dreaming brings.