Can you please tell me how high and low impact aerobics differ?

Qood question: Both are aerobics, a form of exercise that increases your heart rate for a period of time. The impact refers to how hard is the exercise on your joints (back, hips, knees?) high impact is jarring like running, bouncing. Low impact is smooth (like elliptical, swimming, biking.) either is good if you are healthy. Those with joint pain/problems need to be more selective.