What happens to your brain when you fall asleep and stay asleep? What am I doing to mess up this up?

We discussed how bad sleep is hurting us, then we looked at what our brain needs to sleep and how we can consume the minerals and vitamins to feed our brain what it needs to sleep. Now today we look at what is really happening and what we may be doing to mess this delicate system up. 

Confession time... I am doing just about everything wrong :( Blue light late at night, evening snacking, practically no routine....  So, I am not judging but learning along with you.

Let's get into it. 

During sleep, the brain undergoes complex biochemical processes that help regulate rest, memory consolidation, cellular repair, and mood. Several key neurotransmitters and hormones are involved in promoting, maintaining, and regulating different stages of sleep. Here’s an overview of these chemicals, their functions, and the factors influencing them:

1. Melatonin

• Function: Melatonin is often called the "sleep hormone" because it signals the brain that it's time to prepare for sleep. Melatonin release is closely tied to the circadian rhythm, which aligns with the day-night cycle.
• Release: Melatonin is produced by the pineal gland and is released in response to darkness, reaching peak levels at night.
• Influences:
  • Light Exposure: Exposure to blue light from screens or bright light late at night can inhibit melatonin production, disrupting sleep.
  • Age: Melatonin levels tend to decrease with age, which is one reason older adults may experience more sleep disturbances.
  • Lifestyle Factors: Regular sleep schedules reduce light exposure in the evening, and sleep-friendly environments support melatonin production.

2. Adenosine

• Function: Adenosine is an asleep-promoting molecule that builds up in the brain during waking hours, creating a feeling of sleepiness. Its accumulation helps drive the "homeostatic sleep pressure," which increases the need for sleep the longer we’re awake.
• Release: Adenosine levels gradually rise during wakefulness and decrease as we sleep.
• Influences:
  • Caffeine: Caffeine blocks adenosine receptors, which reduces feelings of sleepiness. This is why caffeine can interfere with sleep if consumed too late in the day.
  • Physical Activity: Exercise can lead to faster adenosine buildup, which can support a deeper and more restful sleep.
  • Wakefulness Duration: The longer we are awake, the more adenosine accumulates, increasing sleep pressure and the need for rest.

3. GABA (Gamma-Aminobutyric Acid)

• Function: GABA is an inhibitory neurotransmitter that helps calm brain activity, promoting relaxation and preparing the body for sleep. It plays a central role in inducing deep, slow-wave sleep (SWS), which is essential for physical and mental restoration.
• Release: GABA activity increases during the transition from wakefulness to sleep, helping to quiet neuronal activity.
• Influences:
  • Stress and Anxiety: High levels of stress can lower GABA levels, making it harder to relax and fall asleep.
  • Alcohol and Medications: Some substances, like alcohol and certain sleep medications, increase GABA activity, inducing drowsiness but potentially disrupting sleep quality.
  • Diet: Foods rich in glutamate (like certain meats, vegetables, and cheeses) help the brain synthesize GABA.

4. Serotonin

• Function: Serotonin stabilizes mood, helps control wakefulness, and is a precursor to melatonin. It plays a role in regulating the sleep-wake cycle and helps with entering non-REM sleep.
• Release: Serotonin is produced in the brain and is converted into melatonin as light decreases in the evening.
• Influences:
  • Diet: Foods high in tryptophan (such as turkey, eggs, and nuts) support serotonin production.
  • Sunlight Exposure: Daytime exposure to natural light boosts serotonin production, which improves mood and supports nighttime melatonin production.
  • Mental Health: Low serotonin levels are linked to mood disorders like depression, which are often associated with sleep disturbances.

5. Orexin (Hypocretin)

• Function: Orexin is involved in promoting wakefulness and preventing sudden transitions to sleep, helping maintain a stable sleep-wake cycle. It is essential for sustaining alertness during the day.
• Release: Orexin is active during wakefulness, especially in response to stimulation (like food or social interaction).
• Influences:
  • Daylight: Exposure to natural light and regular daytime activities support orexin production.
  • Circadian Rhythms: An irregular sleep-wake schedule or sleep deprivation can disrupt orexin levels, leading to excessive daytime sleepiness.
  • Diet: Eating too close to bedtime can stimulate orexin production, potentially making it harder to fall asleep.

6. Cortisol

• Function: Cortisol, known as the "stress hormone," helps regulate energy levels and metabolism and contributes to the natural waking process. Its levels are generally low during sleep but gradually increase toward morning to help wake us up.
• Release: Cortisol levels drop during the early part of the night and begin to rise during the later sleep stages, peaking around the time we naturally wake.
• Influences:
  • Stress: Chronic stress or anxiety can lead to elevated cortisol levels, which disrupts sleep by increasing arousal and reducing sleep quality.
  • Exercise Timing: Intense physical activity late in the day can elevate cortisol, making it harder to fall asleep.
  • Regular Sleep Schedule: A consistent sleep-wake routine helps regulate cortisol levels, supporting a healthy sleep cycle.

7. Acetylcholine

• Function: Acetylcholine is a neurotransmitter that plays a key role in REM (rapid eye movement) sleep, the stage associated with dreaming and memory consolidation. It supports brain activity during REM and helps facilitate muscle atonia (paralysis) during this stage.
• Release: Acetylcholine levels rise during REM sleep, stimulating the brain and enabling vivid dreaming while also preventing physical movement.
• Influences:
  • Diet: Foods rich in choline (such as eggs, fish, and soy) support acetylcholine production.
  • Exercise: Regular exercise can help boost acetylcholine levels, which supports REM sleep quality.
  • Mental Activity: Cognitive engagement during the day can help promote acetylcholine synthesis, benefiting both memory and REM sleep.

8. Dopamine

• Function: Dopamine plays a role in regulating sleep-wake cycles, promoting wakefulness during the day. While low dopamine levels can promote sleep, an appropriate balance is crucial for healthy sleep and wake cycles.
• Release: Dopamine levels are generally lower at night, aiding sleep, and begin to rise toward morning to facilitate waking.
• Influences:
  • Daytime Activity: Physical activity and natural sunlight exposure boost dopamine production, improving mood and sleep regulation.
  • Diet: Foods high in tyrosine, like chicken, almonds, and cheese, can support dopamine synthesis.
  • Mental Health: Low dopamine is linked to depression, which can disrupt sleep patterns.

Factors Affecting Sleep Neurochemistry

• Light Exposure: Natural light exposure during the day supports serotonin and dopamine production, while reduced light in the evening promotes melatonin.
• Stress Levels: Chronic stress elevates cortisol and may disrupt GABA and serotonin production, leading to sleep disturbances.
• Diet and Nutrition: Nutrients like tryptophan, magnesium, and B vitamins are essential for synthesizing sleep-related neurotransmitters.
• Physical Activity: Exercise helps regulate cortisol, dopamine, and serotonin levels, promoting sleep stability.
• Sleep Schedule: A regular sleep routine supports circadian rhythms and hormone balance, essential for quality sleep.

In summary, sleep relies on a delicate balance of neurotransmitters and hormones. Each plays a unique role in various stages of sleep, from initiation to maintaining restful, deep sleep and REM cycles. Healthy lifestyle habits, such as balanced nutrition, regular exercise, managing stress, and a consistent sleep routine, are essential for maintaining these neurochemical processes and achieving optimal sleep quality.

Wishing you a good night, all!

Karin