Does weightlessness cause blood clots?
The uncertainty of science: A new study on Earth using an “dry immersion tank” now suggests that weightlessness could increase the chances that female astronauts could get blot clots during long space missions.
First reported in 2020, an International Space Station mission detected an unexpected blood clot in a female astronaut’s jugular vein. To date, space-health research has had more male participants but with the number of female astronauts on the rise, a new SFU–European Space Agency study examined how microgravity affects blood clotting specifically in women. Key findings
- 18 female participants experienced five days of continuous simulated microgravity in a European Space Agency (ESA)-sponsored VIVALDI I dry immersion study.
- Coagulation time (the time it took for blood clots to start forming) was longer.
- Once started, clots formed faster.
- Once formed, the strength and stability of the clots was greater
The dry immersion tank is “a specially designed water bath with a waterproof sheet to keep participants dry while floating, and simulating weightlessness.”
The researchers admit these results are very uncertain. For one, none of the clots that occurred during the study were “clinically concerning,” which means they were the kind of clots that the body deals with normally without threat. The researchers also noted in their paper’s abstract that “current published research on this topic is male-centered,” which explains the female focus of this particular research.
This research suggests that blood clots could be an issue on long missions in weightlessness, but the data is sparse and very incomplete. Moreover, based on more than a quarter century of missions longer than six months in space, it appears the one blood clot cited above might have been the only incident so far recorded. And any results using immersion tanks on Earth is questionable, as they are a poor substitute for actual weightlessness in space.
Nonetheless, these results add weight to the need for developing interplanetary spaceships with some sort of artificial gravity. Without it, the health of any passengers going on long missions to other planets like Mars is certainly at risk, not simply from blood clots but from bone loss, vision damage, spinal deformities, and overall loss of cardio-vascular and muscular strength, all issues that have been documented well in space.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The uncertainty of science: A new study on Earth using an “dry immersion tank” now suggests that weightlessness could increase the chances that female astronauts could get blot clots during long space missions.
First reported in 2020, an International Space Station mission detected an unexpected blood clot in a female astronaut’s jugular vein. To date, space-health research has had more male participants but with the number of female astronauts on the rise, a new SFU–European Space Agency study examined how microgravity affects blood clotting specifically in women. Key findings
- 18 female participants experienced five days of continuous simulated microgravity in a European Space Agency (ESA)-sponsored VIVALDI I dry immersion study.
- Coagulation time (the time it took for blood clots to start forming) was longer.
- Once started, clots formed faster.
- Once formed, the strength and stability of the clots was greater
The dry immersion tank is “a specially designed water bath with a waterproof sheet to keep participants dry while floating, and simulating weightlessness.”
The researchers admit these results are very uncertain. For one, none of the clots that occurred during the study were “clinically concerning,” which means they were the kind of clots that the body deals with normally without threat. The researchers also noted in their paper’s abstract that “current published research on this topic is male-centered,” which explains the female focus of this particular research.
This research suggests that blood clots could be an issue on long missions in weightlessness, but the data is sparse and very incomplete. Moreover, based on more than a quarter century of missions longer than six months in space, it appears the one blood clot cited above might have been the only incident so far recorded. And any results using immersion tanks on Earth is questionable, as they are a poor substitute for actual weightlessness in space.
Nonetheless, these results add weight to the need for developing interplanetary spaceships with some sort of artificial gravity. Without it, the health of any passengers going on long missions to other planets like Mars is certainly at risk, not simply from blood clots but from bone loss, vision damage, spinal deformities, and overall loss of cardio-vascular and muscular strength, all issues that have been documented well in space.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Hope
“A University of Queensland study has shown that a deadly scorpion’s venom carries an extra biochemical sting that could be used to guide future medical treatments and tests. The paper is published in the journal Biochimie. “This work shows that some scorpions can biochemically hijack core components of the clotting cascade in a way we typically associate with some snake venoms. Being novel, they may hold the key to saving lives through controlling blood loss during surgery or after injury.””
I was wondering if a tendency to clot during a space flight might be associated with the higher risk of VTE (venous thromboembolism) with passengers in cramped quarters during airplane flights. The following paper suggests some possible causes for VE’s and DVT’s (deep vein thrombosis) during flights:
https://pmc.ncbi.nlm.nih.gov/articles/PMC8412040/
One of the lines from this that stood out for me was, “This syndrome results from several factors related to the aircraft cabin (immobilization, hypobaric hypoxia, and low humidity) and to the passenger (such as obesity, thrombophilia, oral contraceptive use, hormone replacement therapy, and cancer) that act together, predisposing an individual to excessive blood coagulation, which can result in VTE”.
Obviously people, both men and women, selected for space flight should be in much better physical shape than those of us of the common ruck. So the risk factors noted for things like obesity (and I’d guess high blood pressure) probably don’t apply But I’m wondering what the atmosphere in places like the ISS is like. What’s the atmospheric pressure? What’s the relative humidity?
But with air passenger flights it seems that the biggest single factor is immobility in a single bad position that leads to vein leakage near the knees. That’s got to be a least one simple problem that can be alleviated during an extended tour of a space station: Exercise. Just move around and have some fun in zero-G (or as it’s called now, “microgravity”). Do some simple gymnastics and tumbling in place…move your arms and legs, spin, heck spend 15 minutes a day just having fun and write it off as physical conditioning. Use the exercycle for your legs often, and I hope they’ve got something similar for arms.
I’m hoping that future space stations and habitats will include a space partially dedicated to these kinds of activities because, dang it, space exploration should also be FUN.
Blackwing1: Immobility is not an issue on long space mission. First of all, as you note, they can move around. They aren’t confined to a chair. And weightlessness expands space. Look up. There is a lot of unused cubic footage above our heads we never really use. In space, that all becomes useful and is used.
And exercise is not only a good idea, it is required. To make sure their muscles and bones and cardio-vascular system don’t decline during long missions, astronauts are required to exercise about three hours ever day, using a variety of treadmill devises created for weightlessness.
However, the nature of weightlessness is very similar to bed rest or the immobility of airplane passengers, so your noting of a link here is quite correct.