I actually don't think sitting even more for working 12+ hour days and pulling all nights is good for any of this. I'd love to know more about the OP's health

I actually don't think sitting even more for working 12+ hour days and pulling all nights is good for any of this. I'd love to know more about the OP's health history and physical fitness. I agree that it is easier to work more and harder when you are younger. These are also the best years of your life to build a foundation of fitness for the rest of your life. Pulling all nighters is not health for anyone. It's just when we are younger we are able to bounce back quicker from poor decisions like this.