Caving is a good workout, a good chunk of which is often the hike to get there. Inside the cave all muscle groups are used as you climb, scale, repel, reach, twist, bend and pull yourself along through the cave's paces. Endurance is essential. It does you no good to begin hauling yourself up onto a ledge and feel your arm and shoulder muscles jitter with overexertion. Mentally, you have to be able to remain calm, cool, and collected, no matter what the circumstance.
Panic is the caver's worst enemy.
And when you manage to wiggle free and inch your way to the other end, pull yourself through the impossibly tight exit and crawl gasping out onto the floor of a cavern you've never seen before it's like being reborn. Given a second chance, spit out of a rocky womb and helped to your feet by your friends. That's why I like caving.