The most familiar part of circadian rhythm for most people is the sleep cycle. This is how our bodies normally regulate being awake and being asleep. We can override our bodies, and do almost daily, by creating false beginnings and ends to our sleep cycle. We’re talking alarm clocks and forcing yourself to stay awake when tired. For bipolar disorder, this cycle is extremely important in maintaining functionality and staving off symptoms. This means keeping a regular sleep cycle, even if we have to use the pesky alarm clock. However, there is a lot more to the body’s circadian rhythm and sleep, and it’s all important.
There’s a part of the brain, about the size of an almond, called the hypothalamus. It’s basically responsible for keeping your body in balance. That includes several functions: blood pressure, body temperature, electrolyte balance, appetite/metabolism, sex drive, hormone stimulation and, of course, sleep. In people with bipolar disorder, this body clock is abnormal or arhythmic. Helping the hypothalamus maintain this balance is a key part to managing bipolar disorder symptoms. That involves paying extra attention to what your body needs without unproductive behavior. Being familiar with these functions is the first step to knowing how to manage them.
Sleeping patterns are a major part of bipolar disorder. Abnormalities in sleep patterns are actually part of the diagnostic criteria. In manic episodes, people tend to sleep less or not feel like sleeping at all. For depression, people experience either too much sleep or insomnia when trying to sleep. Too much or too little sleep can actually trigger symptoms. Fun fact: Depressive symptoms are more common in the morning.
There is a term in psychology called psychosocial functioning. It measures things like autonomy, cognitive function, work, activity, relationships and finances. The more successful a person is at achieving these things, the more they are considered “high-functioning.” Basically, these external factors can affect internal balance. If your daily routine is thrown off in some way it can affect body chemistry and, in turn, moods. This can be caused by something as small as skipping a workout or as big as changing careers or beginning or ending a relationship. Some life events just can’t be avoided, but having a routine as an anchor can really help.
Pituitary hormone levels
The hypothalamus is responsible for signaling the pituitary gland to do its thing. It’s in charge of producing several important hormones including thyroid stimulating hormone, human growth hormone, prolactin and adrenocorticotropic hormone. When that last one reaches the adrenal glands, cortisol is produced. When cortisol is produced normally, it helps regulate glucose levels, immune system responses and blood pressure, among other things. When the body is stressed, production of cortisol is increased to help the body cope with that stress. Think the “fight or flight” reaction.
Normally, cortisol levels are highest in the morning and lowest in the evening. When circadian rhythm is off, that can affect the way cortisol is produced. When the production of cortisol is off balance, it can cause serious problems. When cortisol production is sustained at high levels, it can cause elevated blood pressure, sleep problems, lowered immune function, lowered cognitive function, high blood sugar and increased fat storage. When cortisol production is too low, it can cause brain fog, low thyroid function, fatigue and low blood sugar.
Peptides related to the digestive system also work on a biological clock. Ghrelin and leptin help the body with wakefulness and sleep. Ghrelin and cholecystokinin regulate the body’s hunger regulation. When these peptides are out of balance, it can cause increased anxiety, depression and obesity. When cholecystokinin is dysregulated, the effects go all the way back to the hypothalamus and pituitary gland where that cycle can go wrong.
A large part of how the brain determines its cycle is through light. There is a part of the brain called the suprachiasmatic nucleus that transfers light signals from the retina of the eye to the hypothalamus. This is very important. When the eyes detect light, especially natural light, it helps tell the body what time of day it is and thus help regulate the systems of the body.
This is why when there is a lack of sunlight, there is an increased risk of depression. Seasonal affective disorder affects about 5% of the population and 25% of people with bipolar disorder report that their moods shift with seasonal changes. Depression is more common in the winter when there is low light.
The good news is that medications including mood stabilizers like lithium help maintain a normal circadian rhythm. So, if you’re unable to regulate your schedule to help your body out, at least you have a backup. There is also social rhythm therapy that aims to help patients reduce disruptions in social rhythm.
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Photo credit: Aaron Geller