[uncharted9]

An activity or thing that holds deep meaning to you personally will be the stimulant to one's stamina. Love for your child will allow you to take care of him/her despite being insanely sleep deprived. I think the concept is much more broader than just work.

[OutOfHere]

Yes, exactly. The chemicals are intended to make up for the lack of immense love for the organization of the work.