Why is it hard to stairs than down?

Climbing stairs requires more energy and effort than descending because it involves overcoming gravity and engaging more muscle groups, particularly in the legs and core. When going up, the body must work against gravitational pull, which increases the heart rate and demands greater oxygen consumption. In contrast, descending stairs relies more on gravity, allowing for a more passive motion that requires less muscular effort. This difference in energy expenditure is why many people find it harder to go up than down.