What Zone 2 Actually Means
Zone 2 is the intensity at which you can hold a full conversation without gasping, but would struggle to sing. On a heart rate scale, it sits between 60 and 70 percent of your maximum heart rate. For a 35-year-old, that's roughly 111 to 130 beats per minute. Most people blowing past this on a treadmill, chasing a sweat-soaked T-shirt as proof of effort, are training in Zone 3 or 4, the metabolic no-man's-land that is too hard to recover from quickly and not hard enough to produce peak cardiovascular adaptations.
