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What is PAI?

In Mio’s own words, PAI is …

A revolutionary new system that turns the only number that matters—your heart rate—into a single, personal score, showing you how much activity you need to stay healthy. PAI is Personal Activity Intelligence. Rather than just using steps, PAI’s revolutionary algorithm makes sense of your personal heart rate data, giving you a simple number that shows how much activity you need to live a longer, healthier life

PAI is simple … keep your rolling PAI score over 100 and you are going to stay healthy (¹). Some days it is OK to have a PAI score of very little if any, on other days you will make it up. For me a 5 mile run is a PAI score of approx 30 depending on intensity. A 20 mile bike ride of 1 hour 10 mins has a PAI score of 60.

Why Move the Goalposts?

We’ve got very accustomed to measuring our daily activity by the number of steps we take. Working, as I do, for 8 hours per day from home, there are days when I may not even reach 4,000 steps. However, i like to think I am reasonably fit. I exercise every day if possible, but a lot of this time is spent on my bike, turbo trainer, elliptical trainer or doing HiiT training. None of these rack up the step counter … but they are all helping keep me fit. This is what Mio recognised and addressed it with the Slice. PAI resolves this by monitoring daily heart rate intensity instead.

10,000 Steps is 10,000 Steps … Right? Wrong

Here’s a couple of scenarios to illustrate why STEP COUNTING alone may not be working for us …..

Scenario AMr Smith has a sedentary job and does very little, if any, specific exercise. Every day he slowly walks to work and in the evenings he walks his dog, also slowly. His Fitbit Charge 2 informs him every day that he has achieved his daily step target. Well done Mr Smith! However, he’s not even broken out in to a sweat. His heart rate hasn’t once elevated above 90 bpm (under 50% of his MaxHR). YES – he is achieving 10,000 steps per day. NO – he is not going to make any significant improvements to his long term health & fitness. If he was wearing a Mio Slice his weekly PAI score would be less than 20 from a target 100

Scenario BMr Jones also has a sedentary job and does very little, if any, specific exercise. However, every day he strides to work occasionally jogging for 2 to 3 minutes. In the evenings he takes his dog for a power walk. He alternates between hard striding and light jogging. His Garmin Vivosmart HR informs him that he too has achieved his daily step target of 10,000 steps per day. If he was wearing a Mio Slice his weekly PAI score would be in the region of 70-100

Using the daily step method of activity tracking, Mr Smith and Mr Jones have very similar activity levels. They are both walking 10,000 steps per day. However, Mr Jones’s daily activities, often performed at a heart rate over 55% of Max HR, should result in significant improvements to his long term health & fitness. The Mio Slice would clearly identify the difference in the activity profile of Mr Jones & Mr Smith.

The Mio Slice – first watch with PAI score

What Products Support PAI?

Currently the only product that supports PAI in the watch unit as well as the APP is the Mio Slice. However, Mio have incorporated the PAI algorithm in to the APP that supports their other wrist based heart rate products, the Fuse, the Link and the Alpha 2. If you currently want to see PAI on your wrist, as well as APP, then it has to be the Slice. If you are happy to wait until after you’ve trained and review PAI on the APP, then any of the others will do

Mio Slice – live PAI in watch and APP

Mio Fuse – PAI in APP only

Mio Link – PAI in APP only

Mio Alpha 2 – PAI in APP only

The Science Behind PAI

Mio have worked with many fitness professionals including Ulrik Wisløff (Head of CERG and K.G. Jebsen Centre for Exercise in Medicine).

Dr. Wisløff is a true innovator in the field of health and exercise research. He created the PAI system from the HUNT study. The HUNT study involved more than 45,000 people spanning 25 years. From his extensive research, Dr Wisløff identified the level of exercise people personally require to stay healthy. By focusing on quality exercise, such as moderate-to-high intensity exercise, he found that those who kept their PAI score above 100 were more likely to live longer and stay healthier.

Is it just another gimmick?

Honestly, no. I genuinely believe the company who brought us wrist based heart rate monitoring have brought us the next ground-breaking fitness  innovation. PAI makes total sense to me. I know people who do walk 10,000 steps per day and many more, however, they are FAR from fit and they do not live a healthy lifestyle. YES, walking 10,000 steps per day is better than nothing, but it’s not challenging your cardiovascular system, neither is it stressing your muscles. To improve fitness we must stress the CV system and make our muscles work. PAI measures this and the 7 day rolling target of 100 PAI works well. I’m afraid there are a lot of Fitbit users out there who might be shocked to see how LOW their PAI score is. Shocked maybe, but adopting the PAI system over a daily step target will get you fitter, quicker.

How it looks on the PAI App

The screen-grabs below were taken from the Mio PAI app midway through my second week of testing the Slice. A large portion of my weekly PAI score of 110 is from Sunday. This was a 20 mile bike ride (Strava details) with an average HR of 146bpm and a maxHR of 171bpm. It was a reasonably hard ride with a strong headwind on the way home. Stave awarded it a SUFFER SCORE of 51. The Mio Slice awarded a PAI score of 64. As I suggested earlier, for those familiar with Strava’s SUFFER score, PAI is similar. It’s a different algorithm and they figures are NOT directly comparable.

The image below shows the heart rate data from Sunday’s bike ride. The PAI app splits the session in to zones of LOW, MEDIUM and HIGH intensity. Most of my PAI score (31 points) came from the time spent in the HIGH heart rate zone.


¹) What is PAIMioglobal explain PAI is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon properties including, but not limited to,,,,, or Likewise, we are members of other private affiliate programs and may earn comissions on purchases done by referrals at no additional cost for the buyer.