Question: "Should a Christian exercise? What does the Bible say about health?"
Answer: 1 Timothy 4:8 informs us, “For physical training is of some value, but godliness has value for all things, holding promise for both the present life and the life to come.” Notice that the verse does not say that exercise has no value! It says that exercise is valuable, but it holds priorities right by saying that godliness is of greater value. The Apostle Paul also mentions physical training in illustrating spiritual truth. 1 Corinthians 9:24-27, “Do you not know that in a race all the runners run, but only one gets the prize? Run in such a way as to get the prize. Everyone who competes in the games goes into strict training. They do it to get a crown that will not last; but we do it to get a crown that will last forever. Therefore I do not run like a man running aimlessly; I do not fight like a man beating the air. No, I beat my body and make it my slave so that after I have preached to others, I myself will not be disqualified for the prize.” 2 Timothy 2:5, “Similarly, if anyone competes as an athlete, he does not receive the victor's crown unless he competes according to the rules.” 2 Timothy 4:7, “I have fought the good fight, I have finished the race, I have kept the faith.”
So, clearly there is nothing wrong with a Christian exercising. In fact, the Bible is clear that we are to take good care of our bodies (1 Corinthians 6:19-20). Ephesians 5:29 tells us, "After all, no one ever hated his own body, but he feeds and cares for it..." The Bible also warns us against gluttony (Deuteronomy 21:20, Proverbs 23:2, 2 Peter 1:5-7, 2 Timothy 3:1-9, 2 Corinthians 10:5). At the same time, the Bible warns against vanity (1 Samuel 16:7; Proverbs 31:30; 1 Peter 3:3-4). What does the Bible says about health? Be healthy! How do we achieve that goal? By engaging in moderate exercise and eating reasonably. That is the Biblical pattern of health and exercise.