Rate of Perceived Exertion (RPE)
The RPE scale helps you rate how hard you feel you’re working during exercise. You rate your exertion level from one to 10, where one equates to very little exertion and 10 equates to extreme exertion. Your easy/ recovery runs should be working at around three to four on the RPE scale; tempo runs should be around six to seven; intervals around eight to nine; and a full-on sprint should leave you completely breathless, meaning you’re working at level 10 RPE.