Timer Scripting No Idea On Script

Hello, i'm trying to make a breathing sound effect in javascript, and i think timers would be the best. What i had in mind for the script to do was this: If you sprint for 6 seconds (shift + w and shift + arrow up), play a breathing sound. After walking for 8 seconds, it can be repeated, else not. I have no idea on how to do this script, so every help would be great!