Compute personal activity intelligence (PAI) score

Yeah I glazed over the first time I looked at it, but the nuts and bolts of it are it is a 7day exercise intensity & consistency score for optimal health benefits. On average reduces your cardiovascular disease risk by 25%.

Sounds strangely like intensity minutes that garmin already includes. Is that a firstbeat metric? 

I heard the same thing from the founders of PAI, hopefully it is coming soon!

Nope, it is not a firstbeat metric, currently it is provided by the company linked in the original post. I believe it is somewhat similar to intensity minutes, maybe more so to high intensity minutes.

My interpretation is that it's most analogous to training load, but with a focus on the level of cardiovascular activity that was found to reduce the risk of various diseases in their study. Once you reach a particular threshold, more activity does not further reduce the health risks. So more nuanced and personalised than intensity minutes. If your goal is health, it helps answer the question "when have I done enough".

yes. That's what I meant. Intensity minutes is a first beat metric and PAI is from PAI. But ultimately, they are supposedly after the same nd results which is still to get one moving up to that certain point where it is good for general health/well being

Hence, why PAI?

This is how I read it, as well. More personalised than Intensity Minutes in that it adjusts according to variety, fitness levels, etc, on a daily/weekly scoring basis.  (ie the same activity two days in a row gives fewer points on day 2 than it does on day 1). 

I have been using it for a couple of weeks now and I am actually a little dismayed at how it computes the points so... "harshly". I am a beginner, so no "athlete", and it still cut my score WAY down when doing an identical elliptical workout twice in three days. The first day earned me like 21 points after 40 minutes and the second workout, 48 minutes long, earned me only 9! I felt cheated, lol. Intensity minutes were, of course, counted the same.

Perhaps you are getting fitter! Also variety in your exercise regime can help ensure your body doesn't adapt to doing one particular thing very efficiently.

Another possibility - is your watch measuring your heart rate accurately? You can look in the activity record and see if what was recorded matches what you experienced. This might also explain significant variability from one day to the next.  I did some rowing at the gym yesterday, using a chest strap to record the exercise on a different device, and for the first time neglected to set my watch to take HR from the strap. Based on the activity recorded and prior experience I should have earned a PAI of ~30, but my watch didn't seem to notice I was doing anything at all and instead I gained just 1 PAI point!

Oh no, just 1 point! I feel your pain, haha. I would like to think it is me getting fitter already, but it is more likely either the HR of the watch being inaccurate, or maybe it has more to do with what you said about iHealth averaging or sampling, or whatever it was, the HR every 2 minutes rather than continuously. It may have ended up making workout 2 look easier than workout 1 somehow. Anyway, I am watching both metrics and testing them out. Can't wait until they start taking HR direct from Garmin instead.

Glad to find this thread. I've been using PAI score with a fitbit for half a year and it has been very helpful. I just bought a forerunner 245 because I do a lot of hiit type exercise that the fitbit couldn't track accurately. (I pair a chest strap with the 245 for accurate hiit monitoring.) Currently, I'm wearing the 245 on my dominant wrist and a fitbit charge 3 on my other wrist solely so I can still get a PAI score! (I don't have an iphone so I can't do the work around.) PAI Health's customer support seemed pretty confident that Garmin integration is a priority and only "a couple of months" away. I'm looking forward to that.