Living in Micro-gravity
In today's report I watched the most recent Isaac Arthur YouTube video at the time of this posting. It deals with the affects micro-gravity has on biology so in a roundabout way I guess it also fits Actifit. Someday someone might post a report about exercising on a space station. Astronauts have to exercise or else calcium gradually gets lost and the skeletal bones become more brittle. Lack of gravity can also affect fluid in the eyes causing visual problems and fluids in the ear are offset in micro-gravity causing it to become more difficult to maintain the body's balance. The effect is similar to a ship swaying back and forth at sea.
More research has to be done to understand how decreased and micro-gravity affects the human body before humans can go further out in space. It's possible that with rotating spaceships artificial gravity can be created. Different parts of a spaceship rotating at different rates can have different strengths of g-force. Possibly cybernetics and genetic engineering can also be used to help acclimate to differing amounts of g-force.