There's a Latin saying that goes:
Mens sana in corpore sano.
This phrase is usually rendered, "A sound mind in a sound body." It's usually used in contexts encouraging physical exercise as an essential component of mental and psychological well-being. The phrase comes from a second-century AD Roman poet named Juvenal.
He said that men should "pray for a healthy mind in a healthy body." An even earlier saying is attributed to a sixth-century BC Greek philosopher named Thales. The Greek goes like this:
Here's my translation:
"Who is a happy person? It is the one who has a healthy body, an inventive mind, and a teachable nature."
There is no question that one of the best ways to handle mental stress is through physical exercise. Doesn't our mental health depend to a degree upon our physical state as well? The implication is that both physical and mental health proceed from the same principle.
It's true that the spiritual is more important than the physical. Paul says as much in 1 Tim. 4:8. However, this in no way suggests that bodily training is a bad thing. Christians and non-Christians alike recognize the value of physical exercise for overall health and well-being. To be sure, the rewards of physical exercise are "transient and fading" (Benson). In fact, the Greek expression pros oligon may well mean "for a little while" instead of "to a small extent." Either way, we can't sacrifice our spiritual health on the altar of physical exercise. There must be a deeper work on the soul that comes only through the word and prayer. Timothy himself seemed to have had a bent toward outward self-discipline. Paul doesn't disparage this. But the essential thing is and always will be a holiness of life that is "profitable for all things." As Eugene Peterson so beautifully puts it: "Workouts in the gymnasium are useful, but a disciplined life in God is more so."
A good reminder for every athlete!