The answers are all here - they're just not all bundled together.
As memnoch_proxy states:
"Rules modified in .htaccess files are read on every request. /etc/httpd/httpd.conf and /etc/httpd/conf.d/* are not. I trigger new changes to those files using service httpd reload which sends a SIGUSR1 to workers to restart gracefully."
So it sounds to me like you're using .htaccess files to define your re-write rules which apply to your site and/or folder structure.
In order to prevent the rules being re-read and re-interpretted every time the directory or page is accessed the rules need to be placed within the central Apache configuration files for your website.
The location of these rules varies depending on how the systems administrator has laid out the system; on a Red Hat Enterprise Linux environment I would recommend you place them in their a file named
rewrite-rules.conf
located in
/etc/httpd/conf.d
On a system with a default build of Apache you may have to place these at the end of the
httpd.conf
file located in
/usr/local/apache/conf