Hua Tuo said to Pu, “The human body needs physical labor and movement but not to the extreme. Movement aids digestion and activates blood circulation. Thus it can prevent disease, just as a door hinge does not rot. Ancient immortals practiced ‘bear—hanging’ and ‘turning the head like an owl’ to stretch and relax the waist, body and joints in pursuit of longevity. I have a technique called the Five—Animal Frolics, based on the tiger, deer, bear, ape, and bird. This practice cures illness, benefits the limbs, and circulates the Qi. When feeling ill, pick one animal movement for practice. Breaking a sweat results in a rosy complexion, agile body, and good appetite.” Pu practiced the routine and had sharp eyes and ears, and a complete set of teeth into his nineties.
Reference: Five-Animal Exercise “Wu Qin Xi” in History of the Later Han Dynasty or Hou Han Shu ( Chinese Medical Qigong by Tianjun Liu p. 174 )