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Brain Waves and Sleep

Meet your sleep: Brain waves, your best allies.

Where do the five stages of sleep come from? Back to the origins

The exploration of the mysteries of sleep took a truly scientific turn between 1934 and 1938, when the American pioneer Alfred Loomis and his students initiated the analysis of brain electricity, captured on the surface of the scalp. This breakthrough gave rise to electroencephalograms (EEGs), revealing the inner workings of our sleep. At that time, five stages of sleep (A, B, C, D, and E) were defined, marking the beginning of in-depth scientific exploration.

Initially, these stages were characterized by parameters such as sleep onset (Stage A), relaxation (Stage B), sleep onset (Stage C), deep sleep (Stage D), and sleep on deep (Stage E), with each exhibiting distinct characteristics. However, this classification has evolved over time.

Nathaniel Kleitman and William Dement, using more sophisticated equipment, redefined the stages of sleep into four phases (I, II, III, and IV) in 1957. Two years later, in 1959, Michel Jouvet added a fifth phase, paradoxical sleep, characterized by rapid eye movements (PMO) and referred to in English as REM (Rapid Eye Movements). This phase turned out to be the period when intense brain activity coincides with our dreams, a state that Jouvet aptly named "paradoxical sleep."

The five stages of sleep

Each stage of sleep, from falling asleep to the REM phase, offers distinct characteristics. REM sleep, in particular, is the period when intense brain activity coincides with our dreams, a crucial phase named "paradoxical sleep" by Jouvet.

  • Stage I - Falling asleep: This stage establishes the boundary between wakefulness and sleep, characterized by a clear slowing of the alpha rhythm. It represents a short phase, rarely exceeding 3 to 5% of the total sleep duration.
  • Stage II - Slow and Light Sleep: Following falling asleep, this stage places the sleeper at the crossroads between waking up, deep sleep, and paradoxical sleep. It is characterized by irregular waves interspersed with large slow waves.
  • Stages III and IV - Slow and Deep Sleep: These crucial phases of sleep, characterized by slow and high amplitude delta waves, contribute to physical regeneration, repair and construction, erasing fatigue and distributing energy .
  • Stage V - Paradoxical Sleep (REM): This phase represents between 20 and 25% of the total sleep duration. The brain is active but out of sync with the rest of the body. It is here that dreams occur, essential to psychic, intellectual and biological life.

The Link Between Sleep Stages and Brain Waves

These stages of sleep, repeated throughout the sleep cycle, provide a classic scenario of a night's rest. They are closely linked to brain waves, including delta, theta, alpha, beta, and gamma waves, which play an essential role in sleep quality.

  • Delta waves (0-4 Hertz): Corresponding to deep sleep and deep meditation, these waves plunge the brain into a state of tranquility, losing notion of the environment and time.
  • Theta Waves (4-8 Hertz): Inducing an in-between state, Theta waves promote deep relaxation and access to dreams, creating a space where one is neither completely asleep nor completely awake .
  • Alpha Waves (8-12 Hertz): Associated with light relaxation and creativity, Alpha waves promote well-being, alignment, and productivity in ideas.
  • Beta Waves (12-30 Hertz): Activated during total wakefulness, Beta waves are linked to concentration, but too high a level can lead to stress, affecting the body, productivity, and efficiency.
  • Gamma Waves (30-100 Hertz): Information management waves, Gamma waves, at extremely high frequencies, are associated with extreme concentration and complex problem solving.

In our daily reality, we are often immersed in high frequencies. However, meditation, breathing, and relaxation can allow us to descend to lower frequencies, thus offering the possibility of accessing answers, intuitions, and regaining control over our well-being.

Find out more: discover our recent article on sleep and waking up to light!

Our in-depth article explores the different phases of sleep and waking up that play an essential role in our daily lives. Thus, you will discover how light can transform this experience


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