What has worked for me is shifting to hunter gatherer mode when feeling lethargic. I force my body to do stuff just so that my primal needs are completed. For

What has worked for me is shifting to hunter gatherer mode when feeling lethargic. I force my body to do stuff just so that my primal needs are completed. For example, If I don't get a task done, then I won't get dinner today. Procastinate another task and my body doesn't get access to air conditioning/fan. Not feeling like doing a very important task, no water for the entire day. It might sound a bit extreme and counterproductive, but it works wonders cause that's exactly how we have lived for majority of human existence.