- Timid swimmers who don’t let go of the bouys and don’t explore.
2. Audacious swimmers, whose intrepidness shames and fascinates the timid ones.
3. Praia do Flamengo, in a spot called High-Life, where the streets Payasandú and Barão do Flamengo meet.
“In Flamengo, on the beach where [the two streets mentioned above meet] and where the charming women of Laranjeiras, Catete and Botafogo often visit, there’s a sordid mansion, of the most venerable antiquity, in whose soiled frontispiece the passage of time magnanimously erases the tremendous irony painted there in large letters – High-Life.” 
“Early in the morning, Catete has the spectacular amusement of sea baths. At the unembellished beach called High-Life, every morning a lively bunch of people bathe there. Kids, girls and women from the high society, the pretty boys from the rowing clubs, and all castes of men dip their bodies in those calm waters. Along the walls of the wharf there’s another group: those that don’t swim, made up of women that accompany the swimmers of their own sex and of men who go there to think about the beautiful swimmers. These ones, in truth, are worthy of being seen, and some of them feel a certain pleasure in being thought about and to excite the inocent curiousity of the thinkers they adopt these ingenuous pants that leave their legs nude, from the knee down.” 
Here’s an additional mention of High-Life, from 1913, only it starts with a run-on sentence I found hard to parse for translation.
Also, on the Facebook page Rio que foi notícia e virou história , I found a little bit more information regarding High-Life. The place definitely existed prior to these 1910-1913 references I’ve provided, as evidenced from an “Administrative, Merchantile and Industrial Almanac” from 1904, which lists it as an actual establishment, not just a beach.
Such information coincides with mentions I’ve come across of the Hotel Central taking up High-Life’s location in 1915 – all of which tells me the area of the beach took the name of the closest establishment to it.