Many POP3 servers "discourage" too frequent polling.
Use IMAP with IDLE command instead of POP3.
Both fetchmail (program) and gmail (email provider) support IMAP with IDLE.
It would require one fetchmail process per one monitored IMAP account.
fetchamil will keep one IMAP session open permanently.
You should get "near real time" notifications about new emails.
man fetchmail
--idle (since 6.3.3)
(Keyword: idle, since before 6.0.0)
Enable IDLE use (effective only with IMAP). Note that this works with only one folder at a given time. While the idle rcfile keyword had been supported for a long time, the --idle command-line option was added in version 6.3.3. IDLE use means that fetchmail tells the IMAP server to send notice of new messages, so they can be retrieved sooner than would be possible with regular polls.