I can absolutely relate to this quote! While working out may be tiring and drain your energy, it provides the body with endorphins which elevate your mood and actually give your body more energy. Halfway through a run when you're sweating and taking in deep breaths, trying to push yourself forward, you may be physically exhausted but as the day continues you'll find that you feel better and more energetic. Surprise, it was the workout providing you with all that extra energy!