Guiding Your Summer Sleep

Effect of Circadian Rhythm Disturbance on the Human Musculoskeletal System

A summer sleep schedule is one thing I always look forward to. As soon as I get home from the last day of school, I’m sure to turn off the alarms for the next day and either snooze or stay up late, much like other teenagers. Even though you try to follow a different schedule, did you know your body has its internal clock and schedule? Going against your body's internal clock system can cause sleep disorders, which is one reason doctors advise people to sleep on time. But how does sleep directly affect your health, and what are the invisible tolls?

The circadian rhythm is a feedback loop that begins in the morning with a set of proteins, CLOCK, and BMAL1, that turn on other genes that activate Period (PER) and Cryptochrome (CRY) proteins. These proteins are crucial as they signal your body to cool down, slow metabolism, and prepare for sleep. This slow accumulation of PER and CRY builds up with the highest levels just before night and is broken down in the exchange of night and early morning by Casein Kinase 1 (CK1). Light also plays a major factor in this cycle because when light enters your eyes, light detection cells in your retina send signals through the Suprachiasmatic nucleus. A series of signals suppresses melatonin production, raises alertness, and triggers cortisol levels. In contrast, the light-sensitive cells in your eyes no longer send signals at night because the Suprachiasmatic nucleus signals a gland to produce melatonin, a sleep hormone. When this incredibly meticulous cycle is disrupted, due to jet lag, shift work, or delayed sleep, circadian rhythm sleep disorders may occur. Ironically, a lot of healthcare workers have these disorders. While it may seem that these sleep disorders can cause minimal to mild effects, such as sleep problems, they can cascade into detrimental issues such as impaired concentration and decision-making, higher risk of cardiovascular disease, metabolic problems, weakened immune system, and slow motor skills. Thankfully, there are many effective strategies to manage this balance once again, with the easiest being having a consistent sleep schedule and limiting light exposure. So, if you plan to stay up this summer, make sure you know the consequences of fighting against your own body!

References

Rijo-Ferreira, F., Takahashi, J.S. Genomics of circadian rhythms in health and disease. Genome Med 11, 82 (2019). https://doi.org/10.1186/s13073-019-0704-0