Is fencing a good workout?

A genuinely good one, and a sneaky one. An hour of active fencing burns roughly 400-700 calories depending on intensity, comparable to tennis or basketball, through constant footwork, explosive lunges and the isometric work of holding en garde. Fencers' legs do not lie.

What makes it stick where gym routines fail is that the cardio is a side effect: you're too busy solving the opponent to notice you're doing interval training. It also builds things treadmills don't, balance, coordination, reaction time and core rotation.

It's famously one-sided (your lunging leg and weapon arm work hardest), so serious fencers add light cross-training for symmetry. For everyone else: show up twice a week and the fitness takes care of itself.