For years, the gold standard for gauging workout intensity was often a simple "how you feel" metric. And while perceived exertion is still used by many exercisers and athletes today, it’s a bit like ...

Running in zone 2, by definition, should feel easy. And that’s a good thing, considering zone 2 runs make up the majority of any good training plan. These easy efforts serve as the building blocks for ...

To train smarter, you need to understand your ticker ...