PAI: The activity tracker that takes data science to the next level



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Be it the fancy Apple Watch, one of many available FitBit devices or countless other trackers rolled out by brands such as Under Armour, Jawbone and Xiaomi, these wearables track our heart rates, the steps we take, the miles we travel and the calories we burn. Some of them, like FitBit, encourage us to walk two to three minutes every hour throughout the day. If only there were a tracker that could tell us how much exercise we should be doing to reduce our risk of developing cardiovascular disease. Well, good news, everyone.


A matter of life and death

PAI ScoreA research team from the Cardiac Exercise Research Group (CERG) teamed up with Canadian wearable company Mio Global to develop a novel activity tracker that uses heart rate data to personalize the amount of exercise you need to reduce the risk of death from cardiovascular disease. The team discussed the science behind the Personal Activity Intelligence (PAI) tracker on Saturday, Aug. 27 at the ESC Congress 2016.

One of the questions that has resulted from the proliferation of trackers and the different types of data they offer is how a user should leverage all that information. Is there such a thing as too much data? The goal behind PAI's development was, therefore, to make sense of measured heart rate data — the single-most accurate reflection of the body's response to activity — and offer an individual metric that aims to help people achieve optimal health.

PAI communicates with your MIO tracking device and translates heart rate data from any physical activity (walking, swimming, dancing, cycling, etc.) and personal information (age, gender, resting and maximum heart rate) into one simple score.

"The goal is to keep your PAI score above 100 over a seven-day rolling window to protect yourself from premature death related to heart disease," explained lead author Dr. Javaid Nauman, a researcher in the Cardiac Exercise Research Group (CERG), Norwegian University of Science and Technology in Trondheim, Norway. "The health benefits of regular exercise are well established, but individuals do not know how much they need to prevent cardiovascular disease and premature death."

PAI ScoreESC guidelines recommend adults do 150 minutes of moderate or 75 minutes of vigorous exercise weekly, or a combination of intensities to achieve the same energy expenditure. But each year lack of exercise contributes to more than 5 million deaths globally and, in Europe, more than €80 billion in health care.

"People may be insufficiently active because they do not have personalized, meaningful information about how much physical activity they require, and at what intensity," said Dr Nauman.


Making sense of the numbers

To develop PAI, the researchers used data on 4,637 individuals from the HUNT Fitness Study. An algorithm was derived based on questions relating to frequency, duration and intensity of exercise where relative intensities of low, medium and high corresponded to 44%, 73% and 83% of heart rate reserve.

The algorithm was validated in 39,298 healthy Norwegian men and women from the Hunt Study. Participants were divided into four groups according to their PAI score (0, 1-50, 51-99, >100). A score of 0 was considered inactive and used as the reference group for comparison. After a median follow-up of 28.7 years, there were 10,062 deaths, including 3,867 deaths from cardiovascular disease.

Men and women with a PAI level >100 had 17% and 23% reduced risk of cardiovascular disease mortality compared with the inactive group, respectively, after adjustment for multiple confounders. The corresponding risk reduction for all-cause mortality was 13% and 17% for men and women, respectively. PAI level >100 was associated with similar reductions in all-cause and cardiovascular disease mortality regardless of age and risk factors such as smoking, hypertension or being overweight or obese.

The reductions in risk of all-cause and cardiovascular mortality compared to the inactive group were dose dependent by PAI score (1-50, 51-99, >100), with those achieving the recommended level of >100 PAI having the highest reductions in risk.


A slice of useful data science

Everyone can benefit from PAI, Dr. Nauman points out. "PAI is for everyone, young and old, fit and unfit, and it's an easy-to-understand number," he said. "Regardless of the physical activity, every time you raise your heart rate, you contribute to your PAI score, which can be calculated with the PAI app."

The more you elevate your heart rate during exercise, the quicker you accumulate PAI points. But if you're not terribly fit and move a little slower, you can still aim to keep your PAI score at 100 or above by working out at lower intensities for longer durations.

You can download the free Mio PAI app now:

Download on the App StoreGet it on Google Play  

The European Society of Cardiology (ESC) brings together health care professionals from more than 120 countries, working to advance cardiovascular medicine and help people lead longer, healthier lives. The ESC Congress is the world's largest gathering of cardiovascular professionals contributing to global awareness of the latest clinical trials and breakthrough discoveries. ESC Congress 2016 if being held from Aug. 27-31 at the Fiera di Roma in Rome, Italy.