While there are plenty of fancy gadgets you can use to track your effort in the gym or on a run, there’s one core metric that uses no tech at all: the rate of perceived exertion. RPE in the most basic ...

RPE, a.k.a. your Rate of Perceived Exertion, may not be a metric you've used to track your workouts thus far, but experts say it may well be more useful than using a fitness watch. In short, the RPE ...