Yes, you need to have good health to undertake this Chardham yatra. You should be physically and mentally fit and should not be suffering from any kind of breathing problem. It is mandatory to carry some general meditations and a first aid box along with you even though you are fully fine. You also need to have a fitness certificate for trekking to Kedarnath Dham Which can be taken at Guptkashi or Sonprayag. Your fitness check will be done at the Sonprayag Check post for the trekking.