Causes affecting the heart

Among the causes affecting the heart are special causes, as well as causes common to the heart with other organs. These are the causes that act on nature, the causes that cause tumors, the causes that cause the disintegration of the whole, and other similar phenomena that we have already listed in the Book on General Issues. However, the heart is also affected by special reasons that depend on breathing, as well as reasons associated with mental experiences.

As for breathing, when it is constricted or very hot or very cold, damage necessarily occurs in the heart because of this, and with regard to mental experiences, one should refer to what is said in the Book on General Issues, we have already explained how they act on the heart through the pneuma. Anything that overly affects the heart, suffocating and directing the innate heat inward or sending it outward, can sometimes cause fainting and even lead to death. Anger has the weakest effect of such experiences, for anger rarely destroys a person; As for insomnia, intense work and the like, all this weakens the heart, dissipating pneuma.