Episode 134: Martian Medicine 101 - a podcast by Rio Bravo Family Medicine Residency Program

Episode 134: Martian Medicine 101.    

Future doctor Collins and Dr. Arreaza talk about the health risks of going to space and to Mars, especially the effect of radiation. 

Written by Wendy Collins, MSIII, Ross University School of Medicine. Comments by Hector Arreaza, MD.

You are listening to Rio Bravo qWeek Podcast, your weekly dose of knowledge brought to you by the Rio Bravo Family Medicine Residency Program from Bakersfield, California, a UCLA-affiliated program sponsored by Clinica Sierra Vista, Let Us Be Your Healthcare Home. This podcast was created for educational purposes only. Visit your primary care provider for additional medical advice.

Today is March 31, 2023.

Arreaza: Wendy, I confess I am excited for today’s topic. My love for space began with E.T. (I know, I am old). I was exposed to that famous movie when I was a little kid, and ever since, I have had a tremendous curiosity about space and Mars. Honestly, I did not think this could be a topic for our podcast until I met you. 

Wendy: I got inspired to talk about space medicine because I want to go into this field. My college degree was in Physics, and I was fortunate to do Astrophysics and Particle Physics research as an undergraduate, as well as coral reef research. I am passionate about Medicine and treating patients, but I also love Aerospace Medicine because it’s so interdisciplinary. Flight surgeons get to scuba dive, work on oceanography, botany, engineering projects, and more, and collaborations like that sound exciting to me. Anyways let us talk about what is going on in the industry right now. Dr. Arreaza, do you know what humans are doing in space this year?

Arreaza: I do! I like to watch the launches online and in person. I have seen several SpaceX rockets from my backyard (something I never imagined I could do), and there has been some big news, we are going back to the moon! 

Wendy: Yes! Artemis 1 was a successful unmanned mission to orbit the moon and it was launched in November and landed in December last year. Now we look to Artemis 2, which will be a manned lunar flyby. So, like Artemis 1, but with astronauts onboard. And the goal for future missions after that is to land on the moon, establish a lunar base, and eventually prepare us for a long-term space flight like that to Mars. And there is even a presidential order to land humans on Mars by 2033. 
Arreaza: Yes, it is very exciting! BUT there are many, many human health risks to space flight.

Wendy: Even more for space flight outside of low earth orbit. Because of this, and because space flight is becoming commercialized, space medicine is a growing field, and growing in all medical specialties. Believe it or not, I was just in a talk by a NASA flight surgeon where it was mentioned that NASA is even looking for OB/GYN because 50% of their astronauts are women who need gynecological care, and they currently have to go off-site to receive it.

Arreaza: That’s so cool! I’ve read of a handful of civilian and military aerospace medicine training programs for physicians after residency. And since we’re in Bakersfield and only a stone’s throw away from this campus, why don’t we briefly mention the University of California Los Angeles?

Wendy: Yes, so UCLA established an aerospace fellowship very recently in 2021. That fellowship, unlike the rest of them, is actually for board-certified emergency medicine physicians only right now, I believe the only one that does not consider other specialties like internal medicine and family medicine, but the program is new so who knows that may change. The fellowship’s goal is to train the next generation of space flight surgeons. Part of the medical training includes working in arctic environments, Mars analog missions, which includes rotations at SpaceX and NASA’s jet propulsion laboratory. There are so many new avenues to pursue education and jobs in aerospace medicine but today we’re focusing on some research that’s near and dear, and revolves around how we get to Mars in one piece. You may ask, what are the health risks of going to Mars? Ultimately, I would like to chat about how we mitigate those risks, but first let’s define them.

Arreaza: So, we got some ideas from a paper published in 2020 by Patel et al. It is titled: Red risks for a journey to the red planet: The highest priority human health risks for a mission to Mars. Let’s begin.

Wendy: Spaceflight is dangerous with unique risks and challenges. As a space flight surgeon, your job revolves around ensuring the overall safety of the crew, as well as their physical and mental health and well-being. The major health hazards include radiation, altered gravity fields, and long periods of isolation and confinement. Each of these threats is associated with its own set of physiological and performance risks to the crew.

Arreaza: But crews do not experience stressors independently, so it is important to also consider their combined impact. NASA’s Human Research Program researches over 30 categories of health risks astronauts can face with space flight.

Wendy: Yes, but this article only discusses 4 of those categories, but don’t worry, they are the biggies, they are the “Red Risks.”

Arreaza: So, what are Red Risks?

Wendy: Red Risks are risks that are considered the highest priority due to their greatest likelihood of happening and because they are most detrimental to the crew’s health and performance, which impacts the success of the mission.

Arreaza: There also exists “yellow” and “green” risks too, which of course are important, but less severe or less likely to occur than the Red Risks. 

Wendy: I just want to say I really like the title of this paper. Red risks for a journey to a red planet because Mars of course is red. Anyways as part of this paper, the “red risks” we are going to cover are space radiation health risks. This paper also covers spaceflight-Associated Neuro-ocular Syndrome, which is also known as SANS, behavioral health and performance, and inadequate food and nutrition. But today, we are only going to cover radiation health risks. But one thing this article did not discuss was the human health risk of infection, so let’s briefly mention it now. 

Arreaza: Yes, I can imagine spacecrafts are not sterile environments. It would be important to mitigate infections and hygiene necessities and have antibiotics that are functional and not expired or altered by radiation. Alright let’s start with the first health risk on the list, radiation.

Wendy: Space radiation health risk is a large topic because it does not just predispose you to cancer, it also affects many organ systems. So, we are going to break down the health risks caused by space radiation exposure into of course radiation carcinogenesis, but also cardiovascular disease, degenerative tissue effects, and lastly acute in-flight as well as late central nervous system effects. 

Arreaza:

Wendy: Yes the spacecraft does filter some radiation of course, but not Earth’s atmosphere. It’s actually a common misconception that astronauts on the International Space Station are protected by Earth’s atmosphere. But it’s not the atmosphere, it’s Earth’s magnetosphere, which is protective from radiation on some level because it absorbs many high-energy protons from space that, if not absorbed, would interact and cause damage to whatever is around. 

Arreaza: But astronauts on the ISS are exposed to radiation, how much?

Wendy: So, about one weekon the ISS is approximately equivalent to one year’s exposure to radiation on the ground. But astronauts going to Mars are going to be in space a lot longer than one week. NASA’s 2020 Perseverance rover mission took 7 months to get to Mars.

Arreaza: And that’s without Earth’s magnetosphere, and not considering any travel back home. That’s a lot of radiation. How much radiation exposure would you get traveling to Mars?

Wendy: The crew to Mars would be exposed to pervasive, low dose-rate galactic cosmic rays, and to intermittent solar particle events. 

Arreaza: Wow galactic cosmic rays?

Wendy: Yeah, they sound cool but they’re not the ones that give us superpowers like in the Fantastic Four. It means high charge and high energy protons will come into contact with the spacecraft and all the things inside. While the spacecraft will act as a shield, it will never be an entirely perfect shield and protons will penetrate and interact with human tissues, and you know what that means Dr. Arreaza…

Arreaza: DNA breaks which can cause diseases including cancer, cardiovascular and neurologic disorders. 

Wendy: Exactly. It’s important to note there are so many variables including the spacecraft design, what’s happening with the sun, and the duration of the trip. And because of all these things, the risk assessment for radiation exposure is difficult to pinpoint because it's truly going somewhere we’ve never gone before. The types of radiation encountered in space are very different from the types of radiation exposure we are familiar with here on Earth. There have been radiobiology experiments working on simulating space radiation here on Earth, but we still lack reliable human data.

Arreaza:

 Interestingly, the astronaut with the longest space flight, a Russian physician astronaut Dr. Valeri Polyakov, was on the ISS for 437 days. Dr. Polyakov recently passed away. His cause of death is not disclosed, but he lived a long life into his 80s, so at least we know he did not get terminal cancer after all that time in space.

Wendy: Yes, and that was just Dr. Polyakov’s longest flight. He was on five different Soyuz missions and 2 MIR missions. So, there will be radiation no matter what, what can be done about it?

Arreaza: There’s ongoing research focused on age, sex, and health of the astronaut. Not all people are affected by radiation the same way. Biomarkers are being investigated to determine who will be less sensitive to radiation.

Wendy: Exactly just like we have biomarkers to know if you are predisposed to developing cancers. But back to space.The major cancers of concern from space radiation are epithelial in origin, particularly lung, breast, stomach, colon, and bladder, and leukemias. Radiation is a “red risk” also because of the likelihood of developing cancer after the mission back on Earth. Dr. Polyakov was fortunate to live a long life, but what about our Mars astronauts with even greater radiation exposure?

Arreaza: This research paper even mentions cancer is a long-term health risk and although it is rated as “red”, most research in this area is currently delayed. This is because NASA’s Human Research Program is focusing on in-mission risks, not the risks after the mission. But research is still being done to establish radiation dose thresholds, specifically permissible exposure limits. 

Wendy: So now let us talk about the effects of radiation that is not cancer.

Arreaza: So, we know radiation can cause many other health problems. This includes cardiovascular and cerebrovascular diseases, cataracts, digestive and endocrine disorders, immune deficiencies, and respiratory dysfunction. 

Wendy: Specifically, we know cancer patients who have received high-dose radiation to the mediastinum, are at an increased risk for cardiovascular disease including heart attack and stroke. An astronaut who goes to Mars is more likely to die from a heart or vascular disease secondary to radiation than cancer.

Arreaza: NASA also is concerned about the effects of other inflight risks such as more blood flow to your head without the effect of gravity. Not to mention developing atherosclerosis, myocardial infarction, stroke, or arrhythmia just like anybody else on Earth.

Wendy: There is also chronic inflammation and increased oxidative stress from radiation, which contributes to cardiovascular disease. For example, the mechanism of increased endothelial dysfunction.

Arreaza: Health problems are not only a result of spaceflight but there can be pre-existing conditions. Astronauts are extensively screened medically, but diseases can also arise in astronauts who are “healthy” before leaving. 

Wendy: Absolutely, which is why right now only extremely healthy individuals are candidates to become astronauts, although this will likely change as space becomes more accessible the more spaceflight commercializes.

Arreaza: Other diseases induced by radiation include CNS effects. Acute CNS problems that may arise during flight are impaired cognitive function, motor function, and behavioral changes. These would cause serious problems for astronauts.

Wendy: Besides acute, there are also chronic CNS problems. This includes Alzheimer’s disease, dementia, or accelerated aging. This has been shown with rodents exposed to radiation in which neurons and neural circuits change causing performance deficits.

Arreaza: It is important to note that no astronauts have suffered from life-changing radiation damage illnesses to date.

Wendy: Again, back to Dr. Polyakov is evidence of that. And again, more research needs to be done to understand the significance of radiation to human health and determine how much radiation is too much radiation.
Arreaza: That was Martian Medicine 101. Why are we talking about space medicine in this podcast?

Wendy: Space medicine might be an out-there topic for our Family Medicine podcast. But going into space has given us technologies that help us in our day-to-day in life for non-medical folks, but also for primary care staff. The aural thermometer that takes your temperature by being placed near your ear was developed by NASA. Also, ventricular assist devices LASIK, cochlear implants, and artificial limbs scratch-resistant lenses for glasses, are all works that have contributions from NASA. Anyways, radiation was a fun topic today, but stay tuned for Martian Medicine 102, coming soon when we will talk about the other health risks of going to Mars.

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Conclusion: Now we conclude episode number 134 “Martian Medicine 101.” As you can see, family medicine is unlimited, in the future you may be working on Mars as a family doctor. An inquisitive future doctor, Wendy Collins, explained that radiation is one of the major risks of long space flights because besides cancer, radiation may also cause cardiovascular diseases, immune deficiencies, and respiratory problems. Dr. Arreaza reminded us that radiation does not affect everyone the same way and even though astronauts are screened extensively, at this point it is difficult to determine with precision who will be a perfect fit for space flights. Stay tuned for Martian Medicine 102.

This week we thank Hector Arreaza and Wendy Collins. Audio editing by Adrianne Silva.

Even without trying, every night you go to bed a little wiser. Thanks for listening to Rio Bravo qWeek Podcast. We want to hear from you, send us an email at RioBravoqWeek@clinicasierravista.org, or visit our website riobravofmrp.org/qweek. See you next week! 

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Links:

1. Patel, Z.S., Brunstetter, T.J., Tarver, W.J. et al. Red risks for a journey to the red planet: The highest priority human health risks for a mission to Mars. npj Microgravity 6, 33 (2020). https://doi.org/10.1038/s41526-020-00124-6
2. Royalty-free music used for this episode: Space Orbit by Scott Holmes, downloaded on July 20, 2022 from https://freemusicarchive.org/music/Scott_Holmes/. 

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