Don't get hung up on blood-related issues. POIS is far from having anything to do with it.
0You mentioned that you are sedentary and smoke a lot. It becomes evident that you have anxiety/stress and your body is probably in a constant fight/flight state.
In the past, if POIS existed, men dealt with seeking paid sex or excessive consumption of alcoholic beverages.
These days we are focused on medicines and physiological issues of our body.
To cure your POIS try to focus on something that improves your physical and mental condition, you will probably have to take some psychiatric medication.