Astronauts, a breed apart.

Astronauts are extraordinary people, but I didn't realise thy were this special. The European Space Agency is selecting a crew for a simulated mission to Mars, and here's how they describe the medical screening:

The final eight candidates are all male, aged between 28 and 39, and come from Denmark, Sweden, Germany (2), France (3) and Belgium.

In Moscow they were put through their paces at the Central Clinical Hospital of the Russian Academy of Sciences. There, for several days, they underwent extensive medical examinations, including an ECG at rest and during exercise, X-ray of chest, spine and cervix, ultrasound of internal organs and blood tests.