full/empty feeling

I like trainings that discharge my batteries. I go out full of energy, and I come back empty. Two days ago I did a cross training in the forest. 3’ in low, then 3’ in middle intensity and around like this through 90’ in a steep mountain terrain with snow. After 90 minutes my legs were empty of energy for uphill running. I like this feeling.
Here, some of my night trainings: