夫氣足耐寒,血足耐暑,神足耐饑,精足力綿
One can endure cold when vapours are
 sufficient, heat when blood is sufficient, hunger when spirit is 
sufficient, the force is continuous when essential liquids are 
sufficient. 
This passage belongs to the 精神氣息解, “Explaining essential liquids, spirit, vapours and breath1”
 paragraph. To the usual trio essential liquids, spirit and vapours, breath has been added, probably to show that it is equally important. In the 
quote, it is blood which has been added. Internal practices use to pay more 
attention to what is happening inside the body, the organs and the 
liquids they produce, the blood… and what is not visible but has an impact 
on one’s performance, what we call vigour, vitality, which they 
theorised as vapours and spirit.