Zone 2 is a heart rate zone. It’s associated with the ability to continue to hold conversations, and to avoid Mouth Breathing. It’s where body is more predisposed to burn fat as opposed to glucose.
Zone 2, for you
~133 bpm to ~146 bpm
Zone 2 (and the upper and lower halves of zones 1 & 3) are where the mitochondria will increase in number. Higher mitochondrial density means you have more energy producers producing more energy per volume of input (in this case “input” is heart rate, carb stores, etc).
It’s all the rage right now. It’s also possible that it’s always been important and I’m only just now seeing it everywhere due to the Baader-Meinhof Phenomenon.
It’s also important to do HIIT or other types of high heart rate training, too. You shouldn’t just do zone 2.
Source
- Huberman Labs
- This video, re: mitochondrial density