Your Body in Space: Use It or Lose It (NASA)
"Besides eating and sleeping, what do astronauts spend more time doing in space than anything else? It's exercise.'"
How Do Astronauts Exercise in Space? (PC Mag)
"ARED (Advanced Resistive Exercise Device) was delivered to the ISS by Space Shuttle mission STS-126 in November 2008. Designed for weightlifting in a weightless environment, it consists of two evacuated, pistol-driven canisters with a flywheel mechanism."
Cardiovascular System Gets 'Lazy' in Space; New Study Gets Blood Flowing on Station (NASA)
"Every time we stand up, gravity pulls blood into parts of the body that are below the heart. A simple experiment you can do to prove this is to let your hand hang down for a short time then examine the veins in the back of your hand."