http://airshipdaily.com/blog/01282014-balzac-coffee
The Pleasure and Pains of Coffee,” he
warns coffee-drinkers of the beverage’s near-fatal potential by relating
his own experience:
…
you will fall into horrible sweats, suffer feebleness of the nerves,
and undergo episodes of severe drowsiness. I don't know what would
happen if you kept at it then: a sensible nature counseled me to stop at
this point, seeing that immediate death was not otherwise my fate.
I go to bed at six or seven in the evening,
like the chickens; I’m waked at one o’clock in the morning, and I work
until eight; at eight I sleep again for an hour and a half; then I take a
little something, a cup of black coffee, and go back into my harness
until four. I receive guests, I take a bath, and I go out, and after
dinner I go to bed. I’ll have to lead this life for some months, not to
let myself be snowed under by my debts.
So he sleeps from 7 pm till 1 am or six hours of sleep and then sleeps after work for another 1.5 hours so 7.5 hours of sleep.... not too bad of a schedule but he was relying on caffeine to produce a hyper-alert waking state for his writing. Very fascinating. For his second shift of work....
9:30 A.M. to 4 P.M. (Mind you, he only mentions drinking “a” cup of coffee.)
he’d still have to down a cup of coffee
every 16 minutes. Even if he drank them three at at time (which he
recommends only for those of “particularly vigorous constitutions”), he
would still have to take a coffee break every 48 minutes!
so 6.5 hours of work during the day and 7 hours of work during the night for a 13.5 hour work shift per 24 hours - 7.5 hours of sleep leaves only 3 hours of free time a day for eating/socializing. Wow.
you get roughly four to five cups a day — a
figure notably similar to how much Balzac describes one of his
characters drinking in his story “Venetian Nights.”
Balzac often had a pot simmering away
(contrary to current advice) while he was writing, which was most of the
time. And since he wrote like a machine, it's unlikely that he wasted
much time pouring and drinking. At one point, though, when he was
suffering stomach cramps, he claimed to be drinking only three cups of
black coffee a day. This might be taken as the minimum.