Are you fit for space travel?

Despite the mothballing of the space shuttle program, public and private funding for space travel is ongoing. Over the coming decades, space tourism as well as jobs requiring work in space are expected to climb. Both spaceports and new spacecrafts are in the planning or even construction phases. However, there is one major deficiency. Apparently, there’s currently no consensus on how to approve people for space travel. Researchers, led by Marlene Grenon from the University of California, San Francisco, think we need to remedy that lack.

Today, people who travel in space are almost uniformly fit and healthy and most are in the first half of their lives. That won’t always be the case. Grenon and her colleagues predict that doctors will one day be fielding questions about whether heart patients can withstand liftoff forces or about how long osteoporosis patients can safely live with low or no gravity. Zero gravity can cause a host of problems even in healthy people, how will it affect people who already have one or more infirmity?

So far, the evidence suggests that most people can tolerate the forces (or lack of forces) associated with space travel, even if they have pre-existing conditions. That said, we’re obviously far from knowing all there is to know about the medical effects of space travel. At present, the FAA is putting the onus of ensuring medical safety on the spacecraft operators, asking only for informed consent. This in turn means that prospective travelers will be seeking advice from their own doctors. For this reason, the researchers suggest that physicians begin to compile data and resources to share with their patients. The scientists have put together the following helpful chart as a starting point.

Hypothetical spaceflight considerations for common medical entities

Medical condition	Influence of spaceflight	Preflight intervention
Coronary artery disease	May increase the risk for cardiac dysrhythmias or myocardial ischaemia	If patient decides to fly, ensure that blood pressure and cardiac rhythm are properly controlled
Cerebrovascular disease	Possible altered flow patterns in a carotid lesion	Optimise medical treatment and consider repair as per current guidelines
Peripheral arterial disease	Volume shifts may exacerbate symptoms	Optimise medical management; consider treatment of critical limb ischaemia and claudication
Abdominal/thoracic aortic aneurysm	Impact of linear acceleration during launch could increase the risk of rupture	Consider treating (endovascular or open)
Aortic dissection (type B)	Impact of linear acceleration during launch could worsen the extent of the dissection	Consider treating (endovascular or open)
Chronic obstructive pulmonary disease/asthma	Symptoms may increase with the stress of flight	Optimise medical management
Osteoporosis	Increase in bone loss during spaceflight	Consider bisphosphonate treatments for longer duration flights (probably no effect for suborbital flights)
Cancer	Possibility that immune suppression (and exposure to radiation) may exacerbate condition	Consider postponing flight
History of deep venous thrombosis	Theoretical increased risk of thrombosis with stasis and decreased use of lower extremities	Prophylactic low molecular weight heparin injections during flight
Gastrointestinal reflux	May exacerbate with the lack of gravity	Ensure that patients symptoms are well controlled with appropriate medical therapy
Transient infections (urinary tract infection, pneumonia, ears, skin infection)	Could exacerbate with effects on the immune system, increased growth of bacteria in space, unknown efficacy of common antibiotics with changes in pharmacokinetics and pharmacodynamics	Consider postponing flight until the acute process is resolved
Psychiatric problems	May exacerbate (or possibly improve) state	Ensure that the patient is not a threat to himself/herself or others
Pregnancy	Unknown data on effects	Consider postponing the flight until after pregnancy

Elizabeth Preston has more on this over at Inkfish.


Grenon, S., Saary, J., Gray, G., Vanderploeg, J., & Hughes-Fulford, M. (2012). Can I take a space flight? Considerations for doctors BMJ, 345 (dec13 8) DOI: 10.1136/bmj.e8124