Five years is actually not a long time for science to understand a process as complex as the pathways of the oil after a large spill. Some of the impacts of the Deepwater Horizon spill on the marine life and ecosystems of the Gulf of Mexico will only become visible in future years. We use oil products daily.
First the researchers examined the effects of lowering cortisol to below a normal (or baseline) level. Then they compared the effects of low, medium, high, and very high cortisol levels in patients undergoing cardiac surgery, a procedure that causes a lot of inflammation.
Whatever the cause, at the molecular level, the end result is the increase in silent inflammation. We often think of cortisol as a stress hormone, but in reality it is an anti-stress hormone whose job is to deal with the inflammatory responses that chronic stress is taking on your body. It is meant to be a short-term response to stress, and it works quite well in this capacity.