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.
Low cortisol occurs when the body just can't take that stress anymore and it totally burns out. Symptoms are more fatigue related and include low energy, sadness/depression, light-headedness, salt cravings, heart palpitations, joint stiffness, weakness, and lack of concentration.