§5.33Διὰ τί ὑγιεινὸν τὸ τροφῆς μὲν ὑποστέλλεσθαι, πονεῖν δὲ πλείω;
Why is it healthy to restrict food, and to exert oneself more?
ἢ ὅτι τοῦ νοσεῖν αἴτιον περιττώματος πλῆθος;
Is it because the cause of disease is the abundance of residue?
τοῦτο δὲ γίνεται ἢ διὰ τροφῆς ὑπερβολὴν ἢ διὰ πόνων ἔνδειαν.
And this occurs either through excess of food or through lack of exertion?
§5.34Διὰ τί οὐ δεῖ πυκνοῦν τὴν σάρκα πρὸς ὑγίειαν, ἀλλ’ ἀραιοῦν;
Why is it that, for health, one must not condense the flesh, but make it porous?
ὥσπερ γὰρ πόλις ὑγιεινὴ καὶ τόπος εὔπνους (διὸ καὶ ἡ θάλαττα ὑγιεινὴ), οὕτω καὶ σῶμα τὸ εὔπνουν μᾶλλον ὑγιεινόν.
For just as a healthy city and a well-ventilated place are healthy (which is why the sea is also healthy), so a well-ventilated body is healthier.
δεῖ γὰρ ἢ μὴ ὑπάρχειν μηθὲν περίττωμα, ἢ τούτου ὡς τάχιστα ἀπαλλάττεσθαι· καὶ δεῖ οὕτως ἔχειν τὰ σώματα ὥστε λαμβάνοντα εὐθὺς ἐκκρίνειν τὴν περίττωσιν, καὶ εἶναι ἐν κινήσει καὶ μὴ ἠρεμεῖν.
For there must either be no residue present, or one must rid oneself of it as quickly as possible; and the body must be in such a condition that as soon as it receives anything, it immediately excretes the residue, and remains in motion and does not rest.
τὸ μὲν γὰρ μένον σήπεται, ὥσπερ ὕδωρ, τὸ δὲ σηπόμενον καὶ μὴ κινούμενον νοσοποιεῖ· τὸ δ’ ἐκκρινόμενον πρὸ τοῦ διαφθαρῆναι χωρίζεται.
For that which remains rots, like water, and that which rots and does not move causes disease; but that which is excreted is separated before it is corrupted.
τοῦτ’ οὖν πυκνουμένης μὲν τῆς σαρκὸς οὐ γίνεται (ὡσπερεὶ γὰρ ἐμφράττονται οἱ πόροι), ἀραιουμένης δὲ συμβαίνει.
This, then, does not happen when the flesh is condensed (for the pores are as it were blocked), but occurs when it is made porous.
διὸ καὶ οὐ δεῖ ἐν τῷ ἡλίῳ γυμνὸν βαδίζειν· συνίσταται γὰρ ἡ σάρξ, καὶ κομιδῇ ἀποσαρκοῦνται, καὶ ὑγρότερον τὸ σῶμα γίνεται.
Which is why also one must not walk naked in the sun; for the flesh becomes condensed, and people become completely emaciated, and the body becomes moister.
τὸ μὲν γὰρ ἐντὸς δὴ μένει, τὸ δ’ ἐπιπολῆς ἀπαλλάττεται, ὥσπερ καὶ τὰ κρέα τὰ ἑφθὰ τῶν ὀπτῶν μᾶλλον.
For indeed that which is inside remains, while that on the surface is removed, just as boiled meat does more so than roasted meat.
οὐδὲ τὰ στήθη γυμνὰ ἔχοντα βαδίζειν· ἀπὸ γὰρ τῶν ἄριστα ᾠκοδομημένων ὁ ἥλιος ἀφαιρεῖ ὃ ἥκιστα δεῖται ἀφαιρέσεως, ἀλλὰ μᾶλλον τὰ ἐντός.
Nor should one walk with one's chest bare; for from the best-built parts the sun takes away what least needs taking away, but rather the internal parts need it.
ἐκεῖθεν μὲν οὖν διὰ τὸ πόρρω εἶναι, ἂν μὴ μετὰ πόνου, οὐκ ἔστιν ἱδρῶτ’ ἀναγαγεῖν, ἀπὸ τούτου δὲ διὰ τὸ πρόχειρον εἶναι ῥᾴδιον.
For from the former, because it is far, it is impossible to draw out sweat without exertion, but from the latter, because it is close at hand, it is easy.
§5.35Διὰ τί κοπώδεις οἱ βραχεῖς τῶν περιπάτων;
Why are short walks tiring?
ἢ ὅτι πολλάκις συνίστανται καὶ οὐχ ὁμαλῶς κινοῦνται περὶ τὰς καμπάς;
Is it because they frequently halt and do not move smoothly at the turns?
τὸ δὲ τοιοῦτον κοπῶδες.
And such a thing is tiring.
§5.36Διὰ τὶ ἑστηκότες ἐν τῷ ἡλίῳ μᾶλλον θερμαίνονται ἢ κινούμενοι, καὶ ταῦτα τῆς κινήσεως θερμαντικῆς οὔσης;
Why are those who stand in the sun heated more than those in motion, and that too when motion is heating?
ἢ οὐ πᾶσα κίνησις θερμαίνει, ἀλλ’ ἐνία ψύχει, οἷον καὶ ἐπὶ τῶν τὰς χύτρας τὰς ἑψημένας φυσώντων καὶ κινούντων συμβαίνει.
Or is it that not all motion heats, but some cools, as happens also with those who blow on and stir boiling pots?
εἰ οὖν ἑστηκότι μὲν προσμένει τὸ θερμόν, προσμένον δὲ μᾶλλον θερμαίνει ἢ κινούμενον (ἀεὶ γὰρ τὸ σῶμα ἴδιον ἡμῶν ἀτμίδα τινὰ χλιαρὰν ἀφίησιν ἀφ’ ἑαυτοῦ, ἡ θερμαίνει τὸν ἐγγὺς ἀέρα ὥσπερ δαλὸς παρών), ἠρεμούντων μὲν ἡμῶν θερμὸς γίνεται ὁ περιέχων ἡμᾶς ἀὴρ διὰ τὰ εἰρημένα, κινουμένων δὲ πνεῦμα γίνεται, ὅ καταψύχει ἡμᾶς· πᾶν γὰρ πνεῦμα ψυχρόν ἐστιν.
If, then, the heat remains in one who is standing, and remaining heat heats more than that which is in motion, (for our body always emits a certain lukewarm vapor from itself, which heats the nearby air like a present firebrand), while we are at rest, the surrounding air becomes hot for the reasons mentioned, but when we move, a breeze is produced, which cools us; for every breeze is cold.
§5.37Διὰ τί οἱ ἐπὶ τῶν ἵππων ὀχούμενοι, ὅσῳ ἂν θᾶττον θέῃ ὁ ἵππος, τοσούτῳ μᾶλλον δακρύουσι τὰ ὄμματα, καὶ οἱ πεζοί, ὅσῳ ἂν μᾶλλον τρέχωσιν;
Why is it that those who ride on horses, the faster the horse runs, the more their eyes water, and pedestrians, the faster they run?
πότερον διὰ τὸ ψυχρὸν εἶναι τὸν προσπίπτοντα ἀέρα;
Is it because the oncoming air is cold?
τὸ γὰρ ψῦχος δακρύειν ποιεῖ· συστέλλον γὰρ καὶ πυκνοῦν τὴν σάρκα ἐκκαθαίρει τὸ ὑγρόν.
For cold makes the eyes water; by contracting and condensing the flesh, it squeezes out the moisture.
ἢ διὰ τοὐναντίον;
Or for the opposite reason?
τὸ γὰρ θερμὸν ποιεῖ ἱδρῶτας, τὸ δὲ δάκρυον ἱδρώς τίς ἐστι.
For heat produces sweat, and a tear is a kind of sweat.
διὸ καὶ γίνονται ὑπὸ θερμασίας ἄμφω ταῦτα, καὶ ἁλυκά ἐστιν ὁμοίως.
Therefore both of these arise from heat, and are similarly salty.
ἡ δὲ κίνησις θερμότητα ποιεῖ.
And motion produces heat.
ἢ διὰ τὴν ὑπὸ τοῦ ἀέρος πληγήν;
Or because of the blow of the air?
ὡς γὰρ οἱ ἄνεμοι ταράττουσιν οἱ ἐξ ἐναντίας τὰ ὄμματα, οὕτω καὶ ὁ ἀὴρ ὁ προσπίπτων, ὅσῳ ἂν θᾶττον ἐλαύνῃ ἢ αὐτὸς τρέχῃ, τοσούτῳ μᾶλλον ποιεῖ πληγὴν μαλακήν, δι’ ἣν γίνεται δακρύειν, ἀραιουμένων τῶν τοῦ ὀφθαλμοῦ πόρων ὑπὸ τῆς πληγῆς· πᾶσα γὰρ πληγὴ διαιρετικόν ἐστιν ἢ θλαστικόν.
For just as winds from the opposite direction trouble the eyes, so also the oncoming air, the faster one rides or runs oneself, the more it delivers a soft blow, which causes watering, as the pores of the eye are opened by the blow; for every blow is divisive or crushing.