Science & research

Derived from one of the world’s largest health studies

The new health standard in measuring physical activity.

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Maintaining 100 PAI or more is strongly associated with adding on average 5 years to your life and reducing the risk of cardiovascular disease mortality by an average of 25%.

The science of PAI

The PAI algorithm was derived from one of the world’s largest health studies involving 45,000 people over 25 years, and it has been further validated across broader populations of over 230,000 people, with over a million person-years of data.

The objective was to develop a single, easy-to-understand personalized activity tracking metric that could help everyday people manage their health. The PAI algorithm was the result of this research.

Published studies have demonstrated evidence associating a PAI Score of 100 and above, with reduced risk of mortality across many cohorts and sets of data.

Read published studies

PAI makes sense of heart rate as a metric for physical activity

The most relevant index for measuring if you are physically active enough is PAI, from a health perspective that's all that really matters. Managing your PAI Score helps you reduce your risk of lifestyle related diseases. Simply, it helps you live longer.

Ulrik Wisløff
Professor of Exercise Physiology, NTNU
Head of Cardiac Exercise Research Group

Watch an interview excerpt with Professor Ulrik Wisløff, inventor of PAI, speaking about the origin of PAI and the scientific research behind it.

PAI reduces cardiovascular disease mortality risk for everyone

No condition

CVD risk


CVD risk


CVD risk

Type 2 diabetes

CVD risk

See how the PAI Score works

Improve your cardiorespiratory fitness

Cardiorespiratory fitness is how well your heart and lungs are able to get oxygen around your body. Experts agree that your cardiorespiratory fitness is a leading indicator of your health and longevity.  

The PAI Health app gives you a personal score that tells you exactly how much physical activity you should do to improve your cardiorespiratory fitness. Over time, PAI will help you lead a more active lifestyle, improving your strength, energy levels, mood and sleep patterns.

Learn more about CRF

Published research examining the benefits of PAI