One year in space: Astronaut Scott Kelly says his body feels ‘significantly different’

Doctors have an encyclopedic knowledge of the human body, but there are some things even superstar physicians like Sanjay Gupta, MD, don’t know. NASA astronaut Scott Kelly, who returned from a year aboard the International Space Station in March, recently shared the health effects of his long stay in orbit with Dr. Gupta. Here are some excerpts from their conversation, as reported by CNN. Read the full interview on CNN’s website.

Dr. Gupta: How are you feeling?

Scott Kelly: I felt significantly different coming back … My legs have had kind of a negative reaction to gravity and it’s kind of shocking how for the first couple of weeks my legs were swollen, sore, the joints, my muscles, and when I stood up at night I could tell my whole cardiovascular system wasn’t used to keeping the blood out of my legs … I’m slowly getting better, but I still get up very slowly. I’m not really able to run yet. I think I’m already improving and will over time.

Dr. Gupta: Do you get colds and flu on the International Space Station, or are you protected due to the isolation?

Scott Kelly: A lot of people get congested, but it’s not because of virus or bacteria, part of it’s a fluid shift or part of it is like an allergen, but not like cold or flu. Your skin cells are floating around and other people’s skin cells and we have a good ventilation system that draws that in but, on Earth you would never be breathing in someone else’s skin cells that come off their body.

Also the CO2 on board is 10 times higher than what it is on Earth. One of the ways myself and others react to that is some pretty significant congestion, headaches, in my case, it irritates my eyes. I wouldn’t want to live forever in that kind of CO2 environment. When it gets up around 3.8 millimeters of mercury, it can affect your cognitive ability as well. It’s definitely something to emphasize for future vehicles.