How PAI is Calculated

When Personal Activity Intelligence (PAI™) was developed, it was done so with the primary goal of impacting people's long-term health. In the years following the HUNT Study, which proved PAI can help people live longer, healthier lives, we have discovered that the shorter-term benefits of using the PAI system—motivation, efficiency, and peace of mind—have evolved into as important as the life-changing benefits that PAI offers. While PAI is a simple metric that leads people on the path to better health, the algorithm is based on 25 years of physical activity and health outcomes data of more than 45,000 people. So we've broken down the facts to help you better understand how PAI works, and how you can get the most out of it. 


PAI stands for Personal Activity Intelligence; it’s a scientifically-backed metric that takes your heart rate during all activity (yes, even those that don't involve steps) and translates it into points, known as "PAI points." If you maintain a score of 100 PAI throughout a rolling 7 days then you will gain maximum protection from cardiovascular disease and other lifestyle related diseases.


PAI was proven using the HUNT Study at the The Norwegian University of Science and Technology. HUNT was one of the world's largest health studies ever performed involving 45,000 people. It was concluded that maintaining a PAI score of 100 over a rolling 7 days associated in an average increase in life by up to five years compared to those who did not maintain a PAI score of 100. To learn more about the HUNT Study, please visit 



During your first few weeks of earning PAI, keep in mind that the biggest jump in PAI's health benefits will be between 0 – 50 PAI. Reaching 50 PAI will give you 60% of the risk reduction from lifestyle related diseases (with 100 PAI giving you 100% of the associated benefits).

As a starting point, 50 PAI is a good goal to aim for as you become familiar with how much PAI you earn from various activities and intensity levels. As you continue to earn PAI points and maintain a score of more than 50, it will become more difficult to earn points from the same level of intensity (more on that below). 


How PAI is calculated

While 100 PAI is the ultimate goal, don’t be discouraged if it doesn’t happen right away. It takes some people weeks, even months, to figure out the right mix of activity, intensity-levels and duration to achieve 100 PAI points.

It's good practice to keep track of which activities and at which levels of intensity give you PAI points.

For tips on activities, check out the article 3 activities to increase your heart rate, and the article 6 quick tips to help you earn more PAI.


As mentioned above, as you work towards 100 PAI and beyond, you will find it harder to earn PAI points.

For example, let’s say your PAI score is less than 50 when you begin working out. The more intense your workout is (I.E. the higher your heart rate is) the faster you'll earn points. This is because PAI rewards intensity.

Now let's say you do the same workout at the same intensity a few weeks later when your PAI score is more than 50. You will find it harder to earn the same amount of  PAI points for the same workout at the same intensity.

Here's why: PAI is designed to follow the law of diminishing returns. This means as you continue to gain PAI points, you'll be pushed to turn up the intensity of your workouts. Again, PAI rewards intensity.

Explaining the Law of Diminishing Returns

The law of diminishing returns tells us that when we repeat an action that yields a positive outcome, that positive outcome diminishes over time.

For example...

If an unfit person begins a new workout routine, their fitness level will improve rapidly at the beginning. As they become fitter, the amount of improvement lessens as they approach their physical limit.

You may have heard such terms as ‘hitting the wall’ or ‘reaching your plateau.’ To break through the ‘wall’ or ‘plateau’, more intensity and/or activity is needed because fitness levels have improved.

In the case of PAI, when you first start earning PAI points, you’ll earn points faster between 0-50 points. But the closer you get to 100 PAI and beyond, the harder you’ll need to work (higher intensity) to earn points.

Keep in mind, while it’s harder to gain PAI points the more points you have, you will not lose any health benefits as you gain PAI points. As long as your PAI score is at or above 100, you’re getting maximum protection from lifestyle-related diseases.


As we mentioned above, 100 PAI or above will give you 100% risk reduction from lifestyle related diseases. As your points go below 100, you receive a smaller percentage of the risk reduction. Keeping in mind that 50 PAI = 60% of the benefits and 100 PAI = 100% of the benefits will give you a good idea of where you stand.

If your PAI points are above 100, whether that’s 150, 200 or even 300—while you aren’t receiving any more risk reduction from lifestyle related diseases (because you can’t get more than the most of anything)—there is still great value in knowing you’re getting fitter, feeling better, and doing everything you can to live a longer, healthier life!


PAI is the great equalizer; it’s based on each person’s physical makeup (maximum heart rate, resting heart rate, and the body’s response to exercise.) The activity everyone does to achieve their goal of 100 is unique to them.

The fitter you are the more effort it will take to earn PAI; conversely, the less fit you are, the less effort it will take to earn PAI points (if all 'effort' is counted as equal). That's not to say it's easier for less fit people to earn PAI, but that PAI adjusts to each person's fitness level, and that's one of the great things about PAI—people are challenged at the appropriate level.


While you sleep, SLICE tracks your resting heart rate (RHR). This gives PAI your true resting heart rate which is a primary component of the PAI algorithm. Your RHR will change over time based on your activity levels. The fitter you are, the lower your resting heart rate will typically be, so it's important to wear your SLICE to bed at the beginning, and good practice to continue wearing it to bed so it can update your RHR.

For a more in-depth look at how your sleep is tracked, read how to get a better night's sleep with SLICE.


Here's one last tip. Once you learn what works for you to earn PAI, you can start to ‘bank’ PAI by pre-planning.

If you know you are not going to be able to work out for a few days during the week, start scheduling in some extra activity in advance, giving you the peace of mind that you'll be protected for a few days and won’t feel guilty!


If you have any questions about how PAI works, please don’t hesitate to contact us.

We’d love to hear from you!  

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