Energy and diligence

I'm wondering what the best ways to increase mental and physical energy are. I'm often fatigued, and feel slightly lethargic quite often. I have a lot of energy for intellectual tasks, but seemingly, I am fatigued by mundane chores or such things. I also lack willpower for resisting certain tasks. I believe that a good way to deal with this would be to simply commit to exercising more, but I wonder if there are other ways that Buddhism recommends. Thank you Edit: I think my previous post on lying might be relevant. Could it be that integrity--something encompassing effort, willpower, honesty and consistency--be something that I am currently lacking? Something akin to, perhaps, virya? I'm not sure. Any thoughts?