The Circadian Rhythm and Stages of Sleep
What is Circadian Rhythm?
Studies have proven that there is a 24-hour circadian rhythm governing when we are asleep and when we experience wakefulness. No matter if a person considers themselves a night owl or they work the night shift, the human body, as well as those of animals and plants, are regulated by an internal biological clock called “The Circadian Rhythm”.
The Circadian Rhythm has its influence when we sleep and when we are awake -this is otherwise known as our sleep-wake cycle. They also govern hormonal release, such as that of growth hormone which occurs mostly when we are amidst the deepest cycle of sleep, as well as our body temperature. When our circadian rhythm has been disrupted or is abnormal, we find there is a strong association with an aftermath that creates obesity, depression, bipolar disorders and diabetes.
When a person has been awake for an extended period, their sleep/wake cycle alerts them that there is a need for sleep, and one consequently becomes drowsy. Ordinarily, the circadian rhythm regulates the timing of sleep and wakefulness at differing times during a 24-hour span.
Between the hours of 2-4am, most adults experience the highest drive to sleep.
Interesting alongside this information is that we are also driven to sleep between the hours of 1 – 3 pm. Those with sleeplessness requiring an insomnia treatmentÂ will suffer most at these times of the day according to our natural circadian rhythm.
Brain Waves and Sleep Cycles
Beta is the “Waking Consciousness” and the brain wave responsible for reasoning.
Alpha brain waves are more often present in deep relaxation. When we are awake, it is Alpha that may slip us into a daydream and also assists in light meditation. Alpha helps focus us through this quiet balancing of the mind. Alpha brain waves are present when our intuitive facilities are optimised.
Theta is the light meditation and sleeping brain wave. It includes REM dream state.
Delta is our deep sleep brain wave. It is the realm of our unconscious mind and is linked to the regeneration that occurs during deep sleep. It is called delta sleep because of the presence of high-amplitude, low-frequency delta waves that are seen to occur in the EEG. People are difficult to rouse once they are in Deep Sleep. Deep sleep is extremely effective in decreasing the sleep drive that builds steadily over the course of the day. Human growth hormone is released in pulses during deep sleep.
The Stages of Sleep
Once our brains begin to enter Theta we are slightly awake and yet in a light state of sleep. Therefore we can be woken easily if disturbed in a Theta state. If undisturbed within 5-7 minutes most people will reach the 2nd stage of sleep.