Why are the "flights climbed" on my iPhone heart app consistently too low?

I believe it tries to calculate a flight of stairs by reaching a landing (or pausing) of some sort after an elevation gain of about 10 feet, since that would be similar to walking up 1 story in a building. If it detects the landing at 8ft in elevation before the landing it will still count that as a flight of stairs. It does not take the elevation gain and divide by 10 to determine a flight of stairs. If you continuously walk up a flight of stairs without pausing for an elevations gain of 20 feet, it would still count that as as 1 flight of stairs, if you pause in the middle, it would be 2 flights. The algorithm may also take into consideration each step having to gain the amount of a standard riser for a stair step. There is no doubt it is not perfect and there could be room for improvement.

Yeah, I am wondering about how it works too. Got my apple watch yesterday. Did my stairs exercise today. It's stairs outside the North Berkeley BART station and there's 11 steps and then 7. I guess it's not quite 10 feet rise in elevation because I went up and down for 20 minutes and it says 0 flights.

I live in a 2 story house with a basement. That currently has water under the furnace and hot water heater and around them. I have been up and down and up and down and up and down more times than I can remember today and it's only 8:45. Spread out towels to mop up, bring up to dryer, back down, back up with another towel, back down, back up with wet sheets ... My guesstimate is 20 flights of stairs today (easily more than a gain of 10 feet) yet my watch says ZERO. It's never been close, but this is ridiculous.