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According to Dr. Iñigo San Millán, an expert in exercise physiology and sports medicine, most recreational athletes don’t spend a lot of time in Zone 2. Instead, they usually skip to zones 3, 4, and 5, where they primarily use carbs as their fuel source. He attributes this to the emphasis on high-intensity training over the past decade. When a lot of people start working out, they’ll do something like P90X or CrossFit — if not those exact programs, then a workout that includes the same kind of form and intensity. We have this idea that if exercise doesn’t feel painful and uncomfortable, it’s not doing anything.
We also jump right past Zone 2 because it’s simply really easy to do, unless you intentionally try to dial back your effort. When you go out for a jog, you probably run at a pace that isn’t a sprint, but does leave you huffing and puffing. This feels like a “normal” pace to you, but you’re almost assuredly in Zone 3 or higher.
Unlike the way most people typically do their cardio, Zone 2 doesn’t feel painful or uncomfortable. In fact, you could probably move at that intensity for hours at a time.
This is why people skip over Zone 2. It’s deceptively easy.
But according to a lot of research, you’re missing out on many health and performance benefits by giving Zone 2 cardio the short shrift.