The Importance of The Circadian Rhythm

Dr. Cavanaugh recently did a talk in regards to circadian rhythm and sleep in drosophila melanogaster. Circadian rhythms are rhythms in behavior that occur throughout the day and reoccur every 24 hours. These rhythms are most commonly known to be affected by things such as the amount of light we experience throughout our day, or even the temperature. However, it was found that even in the absence of these factors, the rhythm remained with only slight deviation. Deep down, on the molecular level, we can begin to understand more fully what actually affects the rhythm. One of the most important molecular level clock cells is known as pigment dispersing factor or PDF. The purpose of these cells is to keep the clock cells within the organism all synchronized as well as possible. In their research, they also found that there is an internal series of criteria for sleep. The first of the criteria is that there must be an increase in overall arousal, which decreases one’s responsiveness to sensations. Sleep is regulated by the circadian rhythm, however if a fly was shown to have a mutation in its clock genes and experienced fragmented sleep, it could still get the same amount of sleep overall. Another example is that if one of the flies was kept awake for a day, on the next day they would make up for this loss by sleeping in a longer and deeper state. It is important to have a healthy and consistent circadian rhythm since it has not only internal effects but also external. The flies with sleep deprivation were found to have deficits in memory, aggressive behavior, and courtship.

The article “Yes, Your Sleep Schedule is Making You Sick” by Richard Friedman of the New York Times also talks about the external effects of sleep deprivation and a misaligned circadian rhythm. It opens up by discussing the effect jet lag may have on our mental state. He talks about a patient he had who seemed to be depressed after returning from a trip to Europe, but was in a hypomanic state when returning from a trip out west, being expansive and having many creative ideas. The effects of jet lag can have many different symptoms including fatigue, poor concentration, depression, mood changes, and more. Because of all of the negative side effects of a misaligned circadian rhythm, there have been many attempts to try and solve the problem at hand. One of these solutions is the use of chronotherapy, which alters the circadian rhythm. It involves being exposed to bright light at progressively earlier times in the morning. The reason for doing this is because if you are exposed to bright light earlier in the day, you are more likely to fall asleep earlier at night. It is also advised to avoid blue light from devices such as our cell phones and computers at later times of the day. Researchers have also developed something called wake therapy, which gives an antidepressant benefit to people who have bipolar disorder or severe cases of depression. Patients are woken up approximately halfway through their sleep cycle in attempt to align the sleep cycle with other components of the circadian rhythm. These include body temperature and cortisol, the stress hormone. In another study, researchers combined chronotherapy and psychotropic medication, and observed that depressed patients got better within 48 hours of treatment, which is significantly faster than standard antidepressants which take about 4-6 weeks. 

The research study along with this article demonstrate just how important our circadian rhythm is, and that we must do our best to keep it aligned. If we do not, it could lead to a plethora of negative effects that could all be avoided by doing something we all love to do, sleep.

References: 

https://www.nytimes.com/2017/03/10/opinion/sunday/can-sleep-deprivation-cure-depression.html