Stamina is often fueled by stimulant drugs which exert a toll on the user. I used five unique ones this morning, and I know it's going to be tough to get proper sleep. As long as one uses their time well, there is no substitute for work-life balance.
I would argue the original post is talking about stamina on a different scale. Stamina over years. Not over the course of a day or week, fueled by stimulants.
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.
That isn't stamina, but perhaps a corrective for the lack of stamina. The stimulation is meant to increase pleasure, hence making it easier to stick with something. Stamina means the ability to endure the lack of pleasure in pursuit of the good.
That sounds like a false dichotomy as it's suggesting that pleasure may not coexist with the good. Typically they do coexist. Typically it is pursuit of the good that brings innate pleasure. If there is insufficient pleasure from work, it's typically because it's insufficiently good. The chemicals are an attempt to fill the gap.
> That sounds like a false dichotomy as it's suggesting that pleasure may not coexist with the good.
I didn't say they couldn't. But they don't always, for one reason or another. We're flawed, we have bad habits, we have vices, we have disordered tastes, etc. These can steer us away from the good toward destructive ends, even though they may provide us with a cheap and empty source of fleeting pleasure.
> If there is insufficient pleasure from work, it's typically because it's insufficiently good.
Continuing the thought above, there are plenty of things we know that are good for us that we nonetheless don't want to do. We struggle to do them, but this does not mean they are insufficiently good, not in the least! It means we are not sufficiently good. Perseverance (or stamina, to use the author's terminology) means enduring unpleasantness, even suffering, for the sake of the good. The more perfect a human being is, however, the more pleasure is aligned with the good, because a more perfect human being is better aligned with the good. Indeed, in a perfect human being, if the situation demanded it, suffering and dying for a worthy good would be a pleasure.
What is experienced as pleasure is not fixed and determined only by the object, but also conditioned by the subject. The reason is similar to the difference between good and bad taste. Good taste is an alignment with and receptivity to the objective good, while bad taste is rooted in dullness, or a disorder of receptivity, or whatever.