What is zone 2 running and why is everyone doing it?

Zone 2 running is easy, steady running at roughly 60 to 70 percent of your maximum heart rate. It feels slow. You can hold a conversation. And it's popular because it builds your aerobic base without beating you up.

Most runners who try it for the first time are surprised by how slow they have to go. That is normal. A lot of people have been running their easy days too hard for years.

Why people do it

Easy aerobic running trains your heart to pump more per beat and your muscles to use oxygen better. It also barely adds fatigue, so you can run more of it, and more running at low stress is how most people get fitter.

The rough rule used by many coaches is about 80 percent of your running easy and 20 percent hard. Zone 2 is the easy part.

How to find your zone

There are a few ways, and none is exact:

• Talk test. If you can speak in full sentences but couldn't sing, you're near it.
• Nose breathing. If you can breathe through your nose, you're probably low enough.
• Percent of max heart rate. Estimate max as 220 minus your age, then take 60 to 70 percent of it. That formula can be off by 10 beats or more either way, so use it as a starting point.
• Watch zones. Most watches and apps calculate zones for you, and the numbers vary a bit between brands.

For a 35 year old, that's a max of about 185 and a zone 2 range near 111 to 130 beats per minute.

What it looks like in practice

Two or three runs a week of 30 to 60 minutes in that range, with one harder session if you want it. If your pace feels too slow, walk the hills and let your heart rate settle rather than pushing through.

Is it the only thing you need

No. Racing and getting faster still means some harder work. But I think for beginners and anyone building toward a half marathon, more easy running is the single most useful change. If you want the bigger picture, see heart rate zones explained.

On League of Fitness, workouts that sync from Apple Health are scored by intensity and heart rate zones, so how hard you actually work matters more than how long you were out there. For zone 2 itself, a watch or the talk test is all the equipment you need.

If your heart rate jumps unusually high at an easy pace, or you feel chest pain or faintness, see a doctor.