Exercise is a violent motion. The limit to its violence should be a
hurried respiration. Exercise renders the organs of the body hardy
and fit for their functional actions. It makes the absorption of food
stronger, and expedites its assimilation; and it improves nutrition by
increasing heat. It also clears the pores of the skin, and evacuates
superfluities by the strong movement of the lungs. Since, therefore, it
contributes to distribution, care ought to be taken that neither the
stomach nor bowels be loaded with crude and indigestible food or liquids;
for there is a danger lest they should be carried to all parts of the
body before they are properly digested. It is clear then that exercise
ought to be taken before eating. The colour of the urine will point out
the proper time for exercise. When it is watery, it indicates that the
chyme absorbed from the stomach is still undigested. When it is of a deep
yellow colour, and bilious, it shows that digestion had been long ago
accomplished. When it is moderately pale, it indicates that digestion has
just taken place; and this is the proper time for exercise, after having
evacuated whatever excrementitious matters are collected in the bladder
and bowels.
* * * * *
COMMENTARY. The remarks of our author on the effects of exercise are
exceedingly pertinent and comprehensive. See, in like manner, Aëtius
(iii, 2), and Oribasius (Med. Collect. vi, 11.) But Galen is the
great authority on this subject, which he treats of very fully and
philosophically, in the second book of his ‘Hygiene.’ He agrees entirely
with Hippocrates, that the proper time for exercise is before a meal,
because, the excrementitious superfluities being thereby evacuated, the
body is in a fit condition for receiving a new supply. He explains,
however, afterwards, that it is after the digestion and distribution of a
preceding meal have been accomplished that exercise will be most proper.
According to Haly Abbas, exercise is useful for three purposes: 1. For
rousing the innate or natural heat, whereby the processes of digestion
and distribution are accelerated. 2. For opening the pores of the body,
and evacuating its superfluities. 3. For strengthening and rousing the
animal actions, by the friction it occasions. (Theor. v, 2.) Avicenna
gives nearly the same statement of the good effects of exercise. Haly
Abbas forbids exercise immediately after dinner. He adds, that exercise
taken immediately after a meal makes the food descend to the intestines,
where it is absorbed by the veins before it is properly concocted, and
thereby the liver becomes loaded with crudities. (Pract. i, 3.)
Alsaharavius recommends exercise before a meal, but advises it not to be
continued after one feels fatigued and languid. (Theor. ii, 2.) The same
rule is distinctly laid down by Rhases. (Contin. xxxiii.)
It appears that, instead of taking exercise after food, the ancients
were in the practice of indulging in a short sleep after their dinner or
mid-day meal. See Plautus (Mostell. ac. iii, sc. 2, 1. 8), and the note
of Meursius (Ed. Gronov.) Homer says that it is beneficial to old men to
indulge in sleep after the bath and taking food. (Galen. Hyg. 1.)
Plutarch mentions that Cicero was cured of debility of the stomach by
taking moderate exercises. (In vita Cicer.)
It was one of the extravagant opinions of Erasistratus, that exercise is
not at all necessary for the health of the animal frame.