One Small Step For Man, One Giant Leap For… Cardiovascular Diseases?
Landing a man on the Moon was undoubtedly a giant leap for mankind but for the individual men of the Apollo space programme it may have proved a death sentence. Worrying research from the US has found that astronauts who travelled into deep space on lunar missions were five times more likely to have died from cardiovascular disease than those who went into low orbit, or never left Earth.
Already eight astronauts have passed away since the Apollo missions began in 1961 – including Neil Armstrong, who died following complications arising from heart bypass surgery to relieve blocked coronary arteries in 2012.
James Irwin of Apollo 15, who suffered a suspected heart attack on the Moon surface, also died from cardiac arrest in 1991 as did Ronald Evans of Apollo 17 in 1990.
Astronauts are fitter than the general population and have access to the best medical care, meaning that their health is usually better than the general population. Those of comparable age but who never flew, or only achieved low Earth orbit, had less than a one in 10 chance of death from cardiovascular disease. But the chance of death
rose to 43 per cent for those who reached the Moon or deep space, probably because of the impact of deadly space radiation.“We know very little about the effects of deep space radiation on human health, particularly on the cardiovascular system,” said Professor Michael Delp, dean of the College of Human Sciences atFlorida State University.
“This gives us the first glimpse into its adverse effects on humans.” Plans for a lunar base may have to be put on hold until scientists have worked out how to prevent the harmful effects of space radiation. The Apollo programme ran from 1961 to 1972, with 11 manned flights into space between 1968 and 1972.
Of the 24 men who flew into deep space on the Apollo lunar missions, eight have died. Seven of those deaths were included in the study. The eighth man — Edgar Mitchell — died after the data analysis had been completed.
Researchers already feared that high levels of cosmic radiation could cause cancer or even Alzheimer’s disease. Apollo 14’s Astronaut Alan Shepherd died of leukemia in 1998 while Apollo 13’s Jack Swigert also died of cancer in 1982.
But it is the first study to look at the mortality of all Apollo astronauts and make the link to heart health. It is thought that space radiation can severely damage blood vessels in the heart leading to long term weakening. The longest lunar mission, Apollo 17, only spent three days on the surface of the Moon so it is feared the damage could be far worse during longer programmes.
Prof Delp and his colleagues also exposed mice to the type of radiation that Apollo astronauts would have experienced. After six months — the equivalent of 20 human years — the mice demonstrated an impairment of arteries that is known to lead to the development of atherosclerotic cardiovascular disease in humans.
“What the mouse data show is that deep space radiation is harmful to vascular health,” added Prof Delp. The new research throws into doubt plans for future Moon bases or colonies on Mars unless researchers can find a way to shield space travellers from the deadly
National space organisations such as Nasa and the European Space Agency and Russia’s Roscosmos are drawing up plans for Moon bases, deep space habitations or future colonies on Mars. Private space company SpaceX, owned by the entrepreneur Elon Musk, is also hoping to land humans on Mars by 2026.
Dr Dorit Donoviel, head of the National Space Biomedical Research Institute, which is helping Nasa understand the health issues faced by astronauts, said there were many physical problems associated with long term space flight.
“I worry about the long term effects of space radiation for cancer, degeneration of tissues, exacerbation of underlying diseases such as heart disease, and brain decrements. There will be radiation exposure during the trip travel to and from Mars, currently estimated to be 6-7 months each way. My next concern would be the Visual Impairment Syndrome which may be due to increased pressure on the brain. If untreated, this could cause optic nerve damage and loss in peripheral vision,” he reported worriedly. “We know the immune system is compromised in space and that viruses and bacterial are more infectious. Medications may expire before they are needed or may not work as well in microgravity or partial gravity because the body processes them differently. Finally, I worry about the consequences on mental health from the isolation. Depression would cause a crew member not to exercise, eat, and take care of his or herself.” The research was published in the journal Scientific Reports.
