A review of treatment plans for the biological clock of astronauts: A systematic review

Abstract

Since the start of civilization and even further back, humankind has been dreaming of flying. Recently, this dream has come true and reached beyond that and sends astronauts to outer space. However, by achieving this milestone, we encountered new problems that were new to humanity. One of the biggest problems is having a sleeping disorder and disruption of the biological clock. It is essential because having a sleep disorder makes astronauts unable to function at 100% capacity, and in outer space, it is dangerous. Some treatments for sleep disorders include drug therapy, such as Dexedrine, temazepam, modafinil, bupropion, melatonin, zolpidem, dextroamphetamine, light treatment, or a trickling sleep/wake schedule, according to NASA's guidelines. This study aimed to review the treatments for sleep disorders and disruption of the biological clock aimed at astronauts during space flights. We presented the different treatments and discussed and oriented the next prospect of research on sleep in space. Therefore, there will be guidelines for astronauts during their flights. Since the beginning of space travel, there have been many papers regarding space and weightlessness on the adverse effects on health. Studies have described the effect of space travel and the environment of microgravity on health. A few studies include both the short- and long-term effects of microgravity on the biological clock. With this new dawn and sending new astronauts to International Space Station (ISS) with NASA and SpaceX commercial Falcon 9 rocket, which opened a new horizon for spaceflights, it is even more important to consider the adverse effects microgravity on health. Purpose: This review aims to specifically analyze the biological clock, sleep deficiency, and circadian disorders. As we acknowledge, there is a sleep deficiency associated with complex microgravity environs and space missions before and after launch. Material and methods: Two researchers searched a thorough and detailed search of the PubMed database with the keywords mentioned below. The search was performed in November 2020 without any time limitations. We only included human studies and articles in the English language. Results: A total of 148 articles were found, and after going through titles, 77 articles were chosen for checking abstracts. Finally, only 12 manuscripts were accepted for data extraction. Conclusion: It is essential for health care involved in space travel providers to help pre-emptively identify problems that may prevent severe consequences during a microgravity environment. Sleep and circadian factors are the fundamental issues of human fatigue, and aviation schedules significantly impact both. We should admire a computerized fatigue model for having a better approach to studying the impact of scheduling.