The Circadian Connection
THE CIRCADIAN RHYTHM
To be healthy is to have rhythm and to be in sync. Our modern lifestyle is disrupting our primordial rhythm of being healthy. Adjusting the timing of how we live, is the key to restoring this rhythm.
A circadian rhythm is a natural, internal process that regulates the sleep-wake cycle and repeats roughly every 24 hours. These 24-hour rhythms are driven by a circadian clock. By restoring our circadian rhythm, we can assist our natural ability to reverse disease and accelerate healing.
When this rhythm is out of sync, it begins to affect different behavioural responses.
Emotional responses
- Stress resulting from disorders of the hypothalamus-pituitary adrenal axis
- Feelings such as exhaustion, increased irritability, mood fluctuations, depressed mood
- Overt behaviour; including frustration, anger, increased impulsivity, mania and increased risk taking, decreased motor performance, increased stimulant and sedative use
Cognitive responses
- Reduced ability to concentrate, difficulty sustaining attention and alertness
- Decreased working memory capacity, reduced memory of facts, events or episodes
- A reduced ability to multitask, make decisions, create and produce
Somatic responses
- Drowsiness
- Microsleep
- Bodily sensations of pain and being chilled
- Cardiovascular disease
- Risk of cancer
- Metabolic problems
- Reduced immunity to disease and viral infection
- Risk of diabetes
MELANOPSIN
Our circadian rhythms adjust to different seasons as well as different types of light. This happens through a light sensing protein in the eye called melanopsin. The melanopsin protein is blue light sensitive. When it is activated by registering blue light, it sends a signal to the brain which responds by thinking it is daytime, regardless of what time it really is. Melanopsin resets the brain clock when daylength changes with each season or when traveling through different time zones. Melanopsin activated at the wrong times disrupts our circadian rhythm and reduces the production of the sleep hormone melatonin. As a result, we cannot reach restorative sleep therefore leaving us feeling sleepy and less alert, as this continues, depression and anxiety arises. Research shows that poor sleep is linked to weight gain, diabetes, heart disease, neurogenerative disease and most other health issues.
MELATONIN
The hormone in the body that is most affected within the processing of blue light is melatonin. Melatonin is widely known as a sleep hormone that regulates the sleep-wake cycle. It is also believed to be the most effective antioxidant. It promotes the expression of antioxidant enzymes. Melatonin has an anti-inflammatory effect. Some studies suggest that melatonin might be useful fighting infectious disease including viral and bacterial infections.
SUPRACHIASMATIC NUCLEUS (SCN)
The melanopsin cells of the retina make direct connection with the suprachiasmatic nucleus (SCN), a tiny region of the brain in the hypothalamus, which is responsible for controlling circadian rhythms. This could be considered as the master clock of the body, which is most sensitive to blue light. The SCN is the link between light and timing, because it receives information about light from the outside world and shares it with the rest of the body. When the SCN gets reset by light, it resets all other clocks that are in the hypothalamus; the pituitary gland, the adrenal gland and the pineal gland. The SCN also tells the brain when to feel hungry and when not to feel hungry. So, in that way, the SCN guides and instructs us when to eat, which indirectly instructs the liver clock, the gut clock, the heart clock and so on.
The diagram below illustrates the connection between blue light, melanopsin, the SCN and melatonin production.
The most effective method to protect our circadian rhythm in a modern society surrounded by artificial light is to utilize blue blocking glasses.