For deep space astronauts, flying to the moon and beyond may induce a greater risk of dying from heart disease compared with astronauts in orbit, a new study revealed.

The new report, which is the first ever research that delved into the long-term effects of deep space travel, cites the effects of cosmic radiation as the reason for a higher heart health-related mortality rate.

Perils Of Deep Space Travel

A team of researchers looked into the fate of 42 astronauts from NASA's Apollo and Gemini missions after returning to Earth.

In the 1960s and 1970s, the Apollo program had sent nine missions and 24 astronauts beyond Earth's low orbit, with the Apollo 11 being the most prominent lunar expedition.

It appears, however, that the missions have taken a toll on the health of astronauts.

The rate of cardiovascular-related deaths among Apollo astronauts is about four to five times higher than astronauts from the same period who only went into low-Earth orbit, or even those who never got into orbit at all.

This indicates that venturing beyond our planet's protective magnetic field could result in long-term damage to a person's cardiovascular system — possibly a consequence of exposure to deep space radiation, researchers say.

In fact, scientists assume that exposure to radiation, together with weightlessness, alters the structure of blood vessels in ways that are known to cause heart disease.

Among the 35 astronauts who stayed in low-Earth orbit for about 15 days, approximately one in 10 died from cardiovascular diseases. Three of the seven lunar astronauts or 43 percent died from heart-related issues.

In a companion study, the team of researchers exposed several lab mice to weightlessness and radiation, and found that the second factor is far more threatening to the cardiovascular system than any other aspect. Weightlessness also did not seem to cause any long-lasting harm to heart health.

Why Is The Study Important?

These days, private companies such as SpaceX and Blue Origin are venturing into the prospect of space tourism. NASA is also planning a future manned mission to Mars.

Michael Delp, first author and lead scientist of the report, believes that with all of these plans to get into deep space, we only have this one small group of astronauts who have actually done it — the Apollo astronauts.

"Nobody had ever looked at their long-term health consequences," says Delp.

Former NASA astronaut Jeff Hoffman says that when it comes to a lunar or deep space mission, speed might be a crucial factor.

He says travelers cannot shield against high-energy radiation in space, especially with current capabilities, but the less time astronauts spend in space, the less they are exposed to radiation.

Hoffman adds that checkups are important for astronauts. He says that he goes to NASA every year for a thorough physical examination. If cardiovascular fitness is lacking, NASA can monitor it for the astronaut annually and hopefully reduce the risk of an early death from cardiovascular problems.

Details of the new study are published in the journal Scientific Reports.

Photo: NASA Goddard Space Flight Center | Flickr