To achieve specific effects on mental or physical performance by increasing dopamine, epinephrine, or serotonin, one must consider baseline levels of these neuromodulators.

“if your goal is to increase your dopamine or epinephrine, to get some particular effect on your mental health, physical performance, et cetera, well, then you need to consider what the background level of dopamine or epinephrine or serotonin happens to be because in doing so, you will know which tool to select and how hard you need to push on that tool, right?”