Caveats: "high-flavonol" isn't quite the same as "chocolate" and the study which used 37 senior volunteers should be replicated.
Excerpted from Science Daily News where you'll find more detail about the researchers and their results.
While revived faculties is the topic, I'll add some senior's humour:
"Auntie George and Uncle Mabel
Fainted at the breakfast table.
But Ovaltine has set them right
and now they do it morn and night,
and Uncle George is hoping soon
to do it in the afternoon"
(Kudos to my late Aunt Nan)