Sleep plays an important role in maintaining our health. Missing out on a good night’s sleep can cause problems the next day.
Sleep gives the body a chance to be recharged from the activities of the previous day and to replenish reserves of energy for the day ahead. This is one reason why we normally awaken in the morning feeling refreshed. With a good night’s rest, both the body and the brain are refreshed and ready for a new day.
Five Brain Waves
An electroencephalograph (EEG) records a person’s brain wave activity. Our brains cycle through five types of brain waves, referred to as Gamma, Alpha, Beta, Theta and Delta. Each type of brain wave represents a different speed of oscillating electrical voltages in the brain.
1. Gamma Waves
* Frequency range: >40 Hz (Highest)
* Higher levels of mental activity: including perception, consciousness, and problem solving activity
2. Beta Waves
* Frequency range: 12 Hz to 40 Hz (High)
* Associated with normal active consciousness such as: focused thinking, alertness and concentration on a task
* Towards the upper end of the Beta range can indicate stressed or anxious thoughts
3. Alpha Waves
* Frequency range: 8 Hz to 12 Hz (Moderate)
* Dominant during states of relaxation or light meditation, daydreaming and creative visualization
* Associated with a sense of peace and calm
4. Theta Waves
* Frequency range: 4 Hz to 8 Hz (Slow)
* Altered states of consciousness and psychic phenomena, as well as enhanced intuition and insight
5. Delta Waves
* Frequency range: 0 Hz to 4 Hz (Slowest)
* Normally experienced during deep (dreamless) sleep or deep meditation
* Linked with the regeneration of the physical body, as well as with the unconscious mind
Five Stages of Sleep
Sleep is divided into two distinct states known as non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM). NREM sleep is also known as quiet sleep. REM sleep is also known as active sleep.
For most people, these two states occur in a roughly 90 minute cycle which is repeated 3 to 5 times a night.
When we sleep, we go through five sleep stages:
Stage one is a very light sleep from which it is easy to wake up. Stage two moves into a slightly deeper sleep. Our deepest sleep occurs in stages three and four. Our brain activity throughout these stages is gradually slowing down so that by deep sleep, we experience nothing but Delta brainwaves—the slowest brainwaves.
About 90 minutes after we go to sleep and after the fourth sleep stage, we begin REM sleep, which is the fifth stage. REM sleep is primarily characterized by movements of the eyes, increased respiration rate and increased brain activity. Brainwaves during this period speed up to awake levels (Alpha or Beta). Most dreaming occurs during REM sleep.
REM sleep is also referred to as paradoxical sleep because, while the brain and other body systems become more active, our muscles become more relaxed, or paralyzed. This paralysis is a built-in protective measure to make sure we don’t act out our dreams.
Do you ever have nightmares or experience stressful situations that you want to escape from? When we are paralyzed, we can’t leap out of bed and run into the wall in the middle of the night, thus harming ourselves.
The four stages outside of REM sleep are called non-REM sleep (NREM). Although most dreams do take place during REM sleep, more recent research has shown that dreams can occur during any of the sleep stages. Most NREM dreams, however, don’t have the intensity of REM dreams.
Contrary to popular belief, it is Delta sleep that is the “deepest” stage of sleep (not REM) and the most restorative. It is Delta sleep that a sleep deprived person’s brain craves the first and foremost. In children, Delta sleep can occupy up to 40% of all sleep time and this is what makes children unwakeable or “dead asleep” during most of the night.
Deep Sleep and Out of Body Travels
When our physical level of Consciousness is in a state of deep sleep (or Delta sleep) and doesn’t have any interference from the mind, we would travel and interact with the higher (or inner) worlds to receive valuable teachings and other information from our spiritual teachers and many inner Beings residing there.
Although such lessons and information are not usually remembered at a conscious waking level in the morning, they are nevertheless permanently stored within our subconscious mind, and in turn our inner bodies. We will gradually benefit from these experiences as we continue to grow spiritually.