Brain waves and their importance for sleep

Alpha, theta, delta – different activities can be observed in our brain during sleep. Depending on the phase of sleep, the brain waves also change. Here you can find out what the different brain frequencies mean and which brain waves occur particularly during sleep.

Table of contents:

1. How do brain waves arise?
2. What brain waves are there?
3. What role do brain waves play in sleep?
4. Can brain waves be influenced?
5. Conclusion

1. How do brain waves arise?

The human brain consists of around 80 billion nerve cells, called neurons, which connect and communicate with each other using electrical impulses. Each of these impulses generates tiny electromagnetic waves with a frequency of up to 100 oscillations per second (100 hertz). The numerous different waves overlap and form an electromagnetic pattern that can be measured using electroencephalography (EEG). Special electrodes are attached to the scalp to record the electrical activity.

The different brain waves can be linked to certain states of consciousness and activities. The more intensively the brain works, the stronger the impulses and vibrations of the nerve cells. Which brain waves occur primarily at a certain moment can therefore provide information about brain activity and show what state our brain and consciousness are currently in.

2. What brain waves are there?

As a rule, 5 types of brain waves are distinguished based on their vibration spectrum: gamma, beta, alpha, theta and delta waves.

Gamma (approx. 40-100 Hz)

Gamma waves are very fast brain waves that enable information to be transferred quickly from one area of ​​the brain to another. They only occur when we are awake and are more pronounced when we are carrying out demanding tasks and a high level of concentration and performance is required. Gamma waves have not yet been studied much, but scientists now suspect that they are also related to the coordination of cell networks in the brain.

Beta (12 – 40 Hz)

Beta waves can be measured when we are in an alert waking state and are therefore the brain waves that predominantly occur during the day in a normal, healthy person. They indicate a state in which we are fully conscious, receptive and concentrated.

Low beta frequencies represent a relaxed but alert state. The middle beta range corresponds to a healthy state of wakefulness with normal performance. A high beta wave range, on the other hand, indicates an increased release of stress hormones and can reflect fear, stress or nervousness.

Alpha (8 – 12 Hz)

Alpha waves are a little slower than beta waves. They usually occur when we go from being awake to being asleep and form a bridge between the conscious and subconscious. We are awake, but very passive and relaxed, our concentration and ability to absorb information is reduced and we are in a kind of stand-by state that can also lead to sleep. Alpha waves are associated with a high ability to learn and remember, which can actually also be seen when transitioning into or out of sleep.Anyone who moves from the theta range (sleep) to a half-sleep (alpha range) when waking up in the morning is likely to be able to remember his dreams If, however, we switch directly to the beta state, we can no longer remember what we dreamed.

Theta (4 – 8 Hz)

When we slowly transition from waking to sleeping, theta waves are mainly seen in the EEG. They arise in a state in which the conscious mind withdraws and the subconscious mind becomes increasingly active. Theta waves are therefore usually found when falling asleep, in the light sleep phases, dream sleep (REM sleep), but also in deep meditation or hypnotic trance. Special features of this phase are a pronounced fantasy, a high level of plastic imagination and the loss of conscious thinking function, which is typical for the dream phases of sleep.

Delta (0.5 – 4 Hz)

The slow delta waves occur mainly in deep sleep and are rarely seen when awake. During these phases we sleep soundly because consciousness is completely disabled. The body, on the other hand, concentrates on regenerative and healing processes, growth hormones are released and the health of all cells and organs is ensured. For this reason, deep sleep is considered one of the body's most important recovery periods, which we never experience consciously but urgently need.

3. What significance do brain waves have for sleep?

Every night we go through several sleep cycles, which are divided into four sleep phases In each of these sleep phases, something different happens in our brain – the Memory is formed, memories are linked together or the energy stores in the body's cells are replenished. Due to these different activities, very specific brain waves appear in the individual sleep phases.

When we sleep, we calm down and conscious activity slows down. Therefore, sleep is mainly associated with the slower theta and delta brain waves.

Before going to bed Ideally, we should start to relax and reduce our activity. Beta waves slow down to alpha waves and we enter a calm, perhaps even sleepy state. When falling asleep The alpha waves usually change into slow theta waves, consciousness fades and we slip into light sleep. transition to the deep sleep phase we are then in the delta wave area. In the following REM sleep brain activity increases again, we dream and primarily theta waves are created.

Brain activity is also very closely linked to energy metabolism. Since almost every neuronal impulse requires energy, energy consumption is significantly higher during periods of high activity (gamma, beta) than during periods of reduced activity. In deep sleep (delta waves), energy consumption in the brain is -40% lower than when awake. This is also the reason why (Deep) sleep allows us to replenish our energy reserves and start the next day full of energy in the truest sense of the word.

Waking from sleep can lead to the beta waves that are typical for waking via alpha waves, or move from the unconscious theta state directly into the beta range. However, those who skip the half-sleep state are less likely to remember their dreams than those for whom the alpha waves serve as a bridge back to consciousness.

The measurement of brain waves plays a major role in sleep research because it can provide information about when we are in which phase of sleep. The EEG is therefore an integral part of the so-called polysomnography (PSG), which is considered the gold standard in sleep medicine for the diagnosis of sleep disorders applies.

4. Can brain waves be influenced?

The human brain is characterized by a high degree of adaptability, which is also known as plasticity. This allows it to adapt its activity to external influences if these dictate a certain rhythm. This can be particularly helpful in diseases such as Parkinson's or Alzheimer's, which are associated with altered brain activity.

To a certain extent, we can also learn to change our brain waves ourselves by controlling our state of consciousness, for example through meditation or hypnosis. But this does not work in all wave ranges. Brain waves can be best influenced in the beta and alpha frequency ranges, i.e. in the active and passive waking states.

Ways to influence brain waves:

• meditation/hypnosis
• Acoustic signals (e.g. binaural rhythms, sounds with certain frequencies)
• Visual stimuli (e.g. strobe light therapy)
• neurofeedback
• Electromagnetic stimulation (e.g. transcranial magnetic stimulation)

5. Conclusion

• Brain waves are created by electrical impulses in the brain and are related to the state of consciousness and activity

• There are 5 types of waves based on frequency: Gamma, Beta, Alpha, Theta and Delta

• During sleep, theta (light sleep, REM sleep) and delta (deep sleep) waves occur primarily

• Brain waves can be partially influenced, for example through meditation, hypnosis, acoustic and visual stimuli or special neurofeedback and stimulation therapies

Best regards and see you soon!