From Dark and Darker Wiki
The 40% Percent Max Health Healing doesn't change, as described, so a shorter buff time means the player will be healed faster... right? "40% percent OVER A TIME of 12s" so if you in crease buff duration it would be something like "40% percent over a time of 15s" with is the same amount of healing, except that it would take longer making buff duration bad for second wind and that whole equation wrong.... right?