Yes, of course the body grows tired. It may feel drained, but it is also being recharged moment by moment. You are part of a cycle of outgoing energy and incoming energy. You see this cycle all around you. Be gentle with the body. When it is running low on energy, refuel it wisely and provide it fresh air and movement. The body will tell you what it needs far more than you may think. Just as you give a plant water, sun, and fertilizer to help it flourish, do the same for the body. Speak lovingly to it. You will be well rewarded.
It and you are so very loved.