Sleep is essential to healing and restoring the body and mind. Sleep and wakefulness have been defined as ‘recurring, behaviour states that reflect coordinated changes in the dynamic functional organization of the brain and that optimize physiology, behaviour, and health.”
“Sleep health” is not just the absence of a disorder or deficit, researchers suggest. Rather, promoting sleep health and education about sleep may help prevent imbalance, as with every other aspect of health. The importance of sleep health is highlighted by new research on the glymphatic system of the brain and CNS. Studies show that this system functions mainly during sleep and is largely disengaged during wakefulness.
Sleep can at times be elusive. In a previous newsletter, we looked at the dysregulation of the hypothalamus-pituitary-adrenal axis (HPA), a major neuroendocrine system that controls reactions to stress and helps regulate digestion, mood, and much more. Stress can disrupt the HPA axis and sleep patterns making us “Wired but tired”. Coined by clinical psychologist Rubin Naiman, the condition is characterized by “racing brain waves, a rapid heart rate, overheated core body temperature and dysfunctional hormonal rhythms… all of which serve to hinder night time sleep and mask daytime sleepiness.”
The physiology of sleep is complex. The hypothalamus contains the suprachiasmatic nucleus (SCN) that is triggered by light-sensitive nerves in the retina of the eye. It uses this to maintain your circadian rhythm (your natural body clock). The pineal gland receives signals from the hypothalamus and increases production of the hormone melatonin, especially at night.
Within the brain and nervous system, the neurotransmitter gamma-aminobutyric acid (GABA) inhibits and regulates the excitatory glutamate, allowing the body and mind to relax. Release of the somnogen adenosine from cells in the basal forebrain, also supports your sleep drive. Caffeine counteracts sleepiness by blocking adenosine.
At night, we cycle about every 90 minutes between rapid eye movement (REM) and non-REM stages of sleep. In non-REM sleep the shift from an awake state to sleep is reflected in changing brain waves, slower heart and breathing rates, and lowered body temp. This stage of sleep becomes deep during the first half of the night. REM sleep follows and is characterized by increased brain activity and side-to-side eye movement behind closed lids. Most dreaming occurs during REM sleep.
Sleep deficits increase as we age according to the American Sleep Association, and may be caused by anxiety, apnea/snoring, medications, alcohol consumption, parasomnia conditions such as sleepwalking and night terrors, and more.
Brain Sarcodes (includes signatures of brain waves)
Glymphatic / Lymphatic Systems (includes signature for Sleep Cycle)