The only time something like that has happened to me it was accidental as I'd played a social match during the morning then unexpectedly got called in to a league match when another player cancelled at the last minute. Luckily I had about 8 hours between the first and second matches to recover.
However if you play in a state tournament (or any tournament) you can often expect to play multiple matches in a day. The last state I did I had to play 8am and 12noon matches on back to back days, one singles and one doubles each day. Not a problem if you are a twenty-something but for us fifty-somethings it was an Advil kind of weekend.
Thanks TW for the version reversion and Xenforo FTW!