As long as we're on the subject of what the ancients advised regarding the connection between physical and spiritual health, we might also touch on the fact that the ancient civilizations appear to have set a rather high regard upon deliberate exposure to the sun.

For instance, Herodotus relates that the fact that the Egyptians shaved their heads and exposed them to the sun, which (he relates) apparently causes the skull to become thick and hard, as opposed to the brittle skulls of those who keep their heads out of the sun.  Here is the passage from Book III of the Histories by Herodotus (translation by George Rawlinson):
On the field where this battle was fought I saw a very wonderful thing which the natives pointed out to me. The bones of the slain lie scattered upon the field in two lots, those of the Persians in one place by themselves, as the bodies lay at the first- those of the Egyptians in another place apart from them. If, then, you strike the Persian skulls, even with a pebble, they are so weak, that you break a hole in them; but the Egyptian skulls are so strong, that you may smite them with a stone and you will scarcely break them in. They gave me the following reason for this difference, which seemed to me likely enough:- The Egyptians (they said) from early childhood have the head shaved, and so by the action of the sun the skull becomes thick and hard. The same cause prevents baldness in Egypt, where you see fewer bald men than in any other land. Such, then, is the reason why the skulls of the Egyptians are so strong. The Persians, on the other hand, have feeble skulls, because they keep themselves shaded from the first, wearing turbans upon their heads. What I have here mentioned I saw with my own eyes, and I observed also the like at Papremis, in the case of the Persians who were killed with Achaeamenes, the son of Darius, by Inarus the Libyan. 
Whatever we think of the propensity of Herodotus to pass along stories that seem a little difficult to believe, it is clear that at least some ancients appear to have believed in a connection between exposure to the sun and the health and strength of the skull, for what it's worth. 

Nor was Herodotus alone in relating belief in the health-giving properties of habitual exposure to the sun.  The writings of other ancient historians including Pliny the Younger contain descriptions of habitual sun-bathing, often after a meal.  Pliny relates that his uncle, Pliny the Elder, was accustomed to such a sun bath every day.  

Other ancient writers and philosophers also appear to have extolled the virtues of habitual daily exposure to the sun for some period of time.  Like other ancient wisdom, this knowledge appears to have been widespread.  The Vedic traditions, for instance, appear to teach a connection between prana and the habitual daily exposure to the sun's rays.

Some modern medical practitioners now argue that deliberate daily exposure to the sun is extremely beneficial (I am not a doctor, so check with them for your specific case).  Dr. Joseph Mercola, who often discusses areas in which he believes that current medical orthodoxy is mistaken or even potentially harmful, has many articles on his website discussing the importance of deliberate exposure to the sun, and with more of the skin than just the hands and face.  Links to some of his discussions of this subject include:
And there are many others.  Dr. Mercola has also written a book about evidence for health benefits of habitual sun exposure.

Even more interesting, perhaps, than the physical benefits of exposure to the sun, however, is the evidence that there may be spiritual benefits to this practice as well. Santos Bonacci, in an interview with Curtis Davis from October of 2011, touches on this important aspect of exposure to the sun  (this is a different interview from the one mentioned in the previous post, but it too can be found on iTunes as a podcast and downloaded for free -- use the search function inside of the iTunes podcast section to look for Santos Bonacci and then look for a date of October 2, 2011).

At 27:51 in that interview, Santos tells us:
The sun provides us with three things, which all begin with "L" -- Love, Light, and Life.  It's the source of all of those things.  So when the rays of the sun bathe us, every atom of our body rejoices.  Our soul is bathed in photons, and this is why we should strip ourselves naked and lie in the sun's rays, as much as we can, to be bathed with those vitalizing little atoms, those electrons and protons which come from the sun.
While we're at it, we may also want to shave our heads as the ancient Egyptians did (according to Herodotus and later Plutarch), to help the skull to grow thick and hard!