Wednesday, May 1, 2019

Circadian Rhythm and Jet Lag


Earlier in the semester on April 16th, we listened to a presentation by Dr. Cavanaugh about his research article titled, “The rhythms of life: what your body clock means to you!” In this article, Dr. Cavanaugh discusses how the circadian rhythms are created and regulated, and the consequences that occur when we try to work against our circadian rhythms.
The circadian rhythm is our internal biological 24-hour clock that controls most of our bodily functions. Dr. Cavanaugh mentions that It controls the rhythmic changes of our “body temperature, blood pressure, levels of cortisol, melatonin and growth hormone, urine production,” and most importantly our sleep. This goes to show just how important the circadian rhythm is to our body’s functioning.
Dr. Cavanaugh then proceeds to explain the molecular clock mechanism that is responsible for producing the circadian rhythm. The circadian time-keeping system has a central pacemaker in the suprachiasmatic nuclei (SCN) in the brain, and secondary clocks in other cells located throughout the body. Individual SCN neurons have been shown to produce 24-hour rhythms in electrical activity. The circadian rhythm is regulated by a negative feedback loop. Clock genes are transcribed to produce clock gene protein complexes, which inhibit further clock gene production. Then these complexes are degraded, which allows the clock genes to undergo transcription once again to produce more complexes. This cycle repeats itself over and over again which “generates a near 24 h rhythm of protein production and degradation, which encodes the biological day,” thus producing the circadian rhythm.
Dr. Cavanaugh then discusses an example of when a circadian rhythm is broken down, known as jet lag. Jet lag results in a plethora of symptoms including fatigue, insomnia, headaches, light-headedness, etc. Jet lag usually occurs when someone flies across multiple time zones. As mentioned earlier, most of the organs in our body have their own circadian clocks. When someone flies across multiple time zones it “uncouples these individual cellular rhythms from the day–night cycle and from each other,” causing your body’s circadian rhythm to fall apart.
A Time Magazine article titled “The Scientific Secrets to Preventing Jet Lag” by Melissa Locker relates to the previously discussed research article. In her article, Locker discusses why jet lag occurs and provides some possible ways on how to overcome it. She explains that jet lag occurs when our body’s circadian rhythm is out of sync with the time zone we are in. This causes a conflict between our mind and body which results in the previously mentioned symptoms of jet lag. Locker states that the best way to alleviate jet lag is to receive proper light exposure. This allows your circadian clock to realign to your current time zone. Another way to try and prevent jet lag from occurring is to shift your body to the new time zone before actually flying by changing your sleeping patterns. The final method Locker mentions to overcome jet lag, is through the use of melatonin. Consuming one to three milligrams of melatonin two hours before you want to go to sleep can be very effective. This is because melatonin is actually a hormone that signals darkness, so it can help adjust your circadian rhythm and eliminate jet lag. Locker’s article provides some directions for the future
            These two studies are directly related because they both describe what the circadian rhythm is and explain how jet lag occurs. Dr. Cavanaugh focused on the biological aspects of the circadian rhythm and the processes behind its formation. While Dr. Cavanaugh, wonderfully explained the concept of jet lag and how it occurs, he did not discuss possible methods to prevent it. This is where Locket’s article comes into play and supports Dr. Cavanaugh’s article. Locket’s article provided multiple suggestions as to how to alleviate the symptoms of jet lag and possibly eliminate its incidence completely. Together, these two articles provide a more holistic view of the circadian rhythm and how it can be disrupted to create jet lag.
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