So, when biking, I noticed that when going up hills, it was less tiring if I went up them more quickly. This is not total Work done as is Force * Distance, as that should be the same.
But the longer one is going uphill, the longer gravity is pulling you backwards. And if you only are providing enough force to counteract the force of gravity (from a stop), you will not make it up the hill, yet you will feel quite tired afterwards. While if one pushes really hard, then one will hardly slow down at all.
I know that if you are coasting, then the conservation of energy applies, and $v_i^2 = v_f^2 + C$ where C is the gravitational potential energy at the top of the hill. But this doesn't explain why it is more taxing to go up a hill slowly than quickly. It's the same amount of energy transformed into gravitational potential anyways.