Astronauts are on average highly educated and have access to top-notch medical care. Their health outcomes are subsequently usually better than the general population. So why are some Apollo astronauts having higher than normal predispositions for heart disease?
The Apollo space program sent 11 manned flights into space with 9 of them being beyond Earth’s orbit into what scientists call “deep space” during its 9 years of running (1961-1972). From Florida State University, researchers evaluated 7 Apollo astronauts out of the 24 total astronauts involved in lunar missions that went into deep space. One-third of these astronauts were dead at the time of the study, and forty percent of these astronauts died from cardiovascular-related complications.
In their study published in the journal Scientific Reports, Florida State researchers subjected mice to deep space-like radiation for six months, the human equivalent of 20 years. Deep space radiation is made up of galactic cosmic rays (GCRs), coming from outside Earth’s solar system but within Earth’s galaxy: the Milky Way. Although researchers are not yet sure what about GCRs causes cardiovascular complications in astronauts exposed to them, they do know that GCRs are made up of atomic nuclei that lose all of their surrounding electrons during their high-speed voyage across the galaxy.
GCRs can also interact with each other and emit gamma rays, another type of radiation scientists known can damage DNA of healthy tissues in the human body.
After six months of GCR radiation, the arteries of the experimental mice showed severe damage, known to lead to the development of atherosclerosis in humans. Atherosclerosis occurs when plaque deposits made up of fat, cholesterol, and calcium build up inside of arteries and cause blockages - it can lead to heart attack, stroke, even death.
For the United States, where orbital missions around the moon are planned for the next two decades in preparation for a manned flight to Mars as well as others planning deep space flights in Russia, China, and the European Space Agency, it is vital to understand soon what causes astronaut heart complications from GCR exposure in order to prevent death later in life.
Deep space radiation is clearly harmful to vascular health, but why? Future research into this relationship will hopefully give scientists more answers.
, Live Science
, National Heart, Lungs, and Blood Institute
, Florida State University