Overtraining and Stress:
One thing that I had to learn the hard way is that more is not necessarily more. For a long period of time, I would hit the gym as well as run multiple miles per day. Eventually, the lack of good sleep and recovery caught up with me and my cortisol and other inflammatory markers went up. The body and nervous system play a critical role in health and well-being, as well as immunity - so it's important to lay off a bit if you're feeling worn down.