Difficult to say, but speaking as a slightly overweight man in his late fifties (1.9 m, 98 kg), I enjoy it! And isn’t that half the battle with exercise?
In a teaching session of just over one hour this week, I burned 357 kcal, and saw my heart rate go from 94-135 bpm.
You might enjoy the following BBC programme with Dr Michael Mosely: Just One Thing - Try Tai Chi (link).
In his short programme, he discussed how Tai Chi, sometimes described as shadow boxing or meditation in motion, might improve one’s balance, immune system, and heart health. It may also be as effective for weight loss as conventional exercise and helpful for improving cognitive function.