The notification email subject and body are language strings. You can use the built in language override functionality shown below to modify it.
www.joomlapolis.com/blog/kyle/18701-language-overrides-have-arrived
Language finder is also built into the language overrides as shown below.
www.joomlapolis.com/blog/kyle/18712-language-key-and-text-finder
The strings specifically are as follows.
Key: [username] has updated their profile!
String:
Code:
<a href="[url]">[username]</a> has updated their profile. Changed: [changed]. Pending Changes: [pending].<br /><br />[changes]
Key: USER_HAS_UPDATED_PROFILE_OF_USERNAME
String:
Code:
[user] has updated the profile of <a href="[url]">[username]</a>. Changed: [changed]. Pending Changes: [pending].<br /><br />[changes]