What counts as exercise in Apple Watch?

It will only get counted as exercise if you started it as a workout or if your heart rate goes up sufficiently. If you are relatively fit, it may require more than walking briskly to achieve that. Make sure that you have your age, sex, height and weight set correctly also.

John Zocco wrote:

Thank you. This explains what I thought was the problem, my heart rate. I'm on medication to slow my heart rate. I've been on it for several years, but I believe I'm over medicated. As an example, last Saturday I went to the gym and got on the treadmill. I did 3.2 mph for 60 minutes and my heart rate averaged 76-81 bpm, not enough to count as exercise, even though by the end I was drenched in sweat. My heart rate should be at 114 bpm (75% of my maximum) and my recommended target range: 83 to 129 beats per minute, according to active.com. I have to talk to my doctor about lowering my dosage and increasing my walking speed. Sorry if it's too much information, but you helped me a lot and I appreciate it.

Oh, the joys of beta blockers! Good luck.

To earn 1 minute of exercise credit(green ring);

Travel a full minute at a brisk walking pace(3.3 mph approx) or above.

Raise your heart rate to approx 75% of your maximum.

When you're at around or above this heart rate for the entire minute you'll receive 1 exercise minute credit.

If you pause or slow down then you won't get any exercise credit.