Other heath risks could also be possible with increased levels, they said.
"According to our estimates, researchers on the surface of Mars can expect a number of adverse factors, such as cardiac arrhythmia, reduced stability and performance, sensory impairments, as well as more long-term consequences in the form of changes at the DNA level, and demineralization of bone tissue," said Anatoly Grigoryev, the deputy head of Russia's Academy of Sciences.
He made the comments at a presentation on the results of the Mars-500 experiment, a ground-based simulation of a mission to Mars that attempted to recreate at least some of the conditions of a flight to the Red Planet by locking six men away in a mock spacecraft for 520 days.
The Moscow-based Mars-500 experiment was completed on Nov. 4, RIA Novosti reported.
Astronauts could also face a number of adverse psycho-physiological factors during the flight to Mars, Grigoryev said, such as hypokinesia -- decreased motor activity -- monotony and frustration.
Exploding whale video goes viral on Internet
Reindeer recovered after escaping from Santa during lighting ceremony