As some of you who follow me on Twitter may already know, NASA astronaut Suni Williams and I were childhood friends. We were on the same swim team together. She is aboard the International Space Station (ISS) at this moment on Expedition 32, beginning a 4-month stay about a week and a half ago. Since her first trip to the ISS in 2006, I've been in touch with her and that got me on the invite list to attend a special launch party for her current mission. At that event, there was a special presentation by Captain Dan Burbank. He was Commander of Expedition 30 to the ISS and returned to Earth on 27 April 2012 after a five-month stay aboard the ISS.
I was curious to learn about the behavior of the astronauts on the ISS in terms of diet, physical activity (especially with regard to bone loss and muscle function) and sleep. Many of you know how our research group examines the role of environmental factors in modifying disease risk. These are GxE, or gene-by-environment, interactions. Diet, dietary components (eg, certain fatty acids, protein content, carbohydrates), exercise (or sedentary behavior) and sleep are key environmental factors for our work.
Dan told me that he would normally consume about 3500 calories per day on Earth but that increased by about 500 calories aboard the ISS. He could not say if it was more carbs or fat or protein or just a bit more of everything. He did not speak much about exercise other than to tell us all during his slide presentation that there is a new resistance machine on board that provides 400 pounds of resistance. The previous machine provided only 100 pounds of resistance and the 400 level is what is needed to stem bone loss. He told us that when one types on a keyboard, only a few strokes are needed to send the person across the room in microgravity. So, they "stand" with feet hooked under railings, like as bar rail. This gives them calluses on the tops of their feet, while those on the soles begin to fade.
What was perhaps the most interesting to me was Captain Dan's sleep habits. He said that on the ISS he needed only 4 to 7 hours of sleep per night. What's more, he did not strap himself in to provide a feeling of lying down, but could sleep anywhere, floating in his room.
All in all, it was a really cool experience to meet an astronaut, to learn about life aboard the ISS, and to see someone I know launch with a Soyuz rocket to begin her latest adventure.
Good luck and continued success with your mission, Suni!