In this European Space Agency blog article, it is argued that the life of a professional athlete shows many similarities to one of an astronaut.
Both need to perform at key moments, and train hard to be at their best.
Exercise and a healthy diet is important for both athletes and astronauts.
Like many preparing for a marathon, a dedicated coach also ensures ESA astronauts are at their peak for launch.
Exercise machines such as treadmills and bikes are used in space on a daily basis.
Read more here.