pretty incredible results. between this and the radiation issue, it makes me question the viability of long term lunar or martian colonies without some serious

pretty incredible results. between this and the radiation issue, it makes me question the viability of long term lunar or martian colonies without some serious advanced in genetic engineering. i'd also be curious of the long terms effects on the heart and circulatory system in low gravity without the strenuous exercise regiment that astronauts have to do. if a future colonist slacked off on exercising for a month would they be able to return to earth and function normally?