Cortisol lowers inflammation and increases blood pressure. The highest levels is in the morning between 6am and 12pm, I would guess that is why most people in the poll feels best during that time. I've made two blood cortisol tests in the morning and both showed levels slightly higher then normal. I believe many POIS'ers has long term hight cortisol due to many POIS inflammations cycles. Although cortisol is the most important player that controls the POIS-inflammation, long term hight levels are producing very bad side effects.
It might also be bad in the short run if its hight all day. When cortisol is hight, the body is closing down many processes, like digestion, repair and immune system. Our bodies dont get enough time to repair itself between the POIS cycles. Thats might be why many people experience problems with digestion, immune system, bad skin, liver/kidney issues.
Thats why we need to focus on things that minimize normal cortisol peaks, like stressmanagement, not drinking tooo much coffee, not too much intense training etcetera. I wish more POIS'ers could do and share more cortisol tests in this forum, specifically tests that shows cortisol many time during the first days after orgasm.