In fact dance based exercise like Zumba, or boxing even, is very helpful with folks suffering Parkinson’s because it require multiple tasks be processed at once - rhythm, hand, foot, observation of the lead. This induces plasticity which is crucial in staving Parkinson’s decline. So I find it strange to assert exercise alone is the beneficial component as it’s clear in pathological situations where increasing plasticity yields slower declines dance and complex exercise that requires many integrated tasks is superior to simple exercise.