When we are in a reclined position (e.g. sitting or lying down) and our energy expenditure does not exceed 1.5 metabolic equivalents of task (METs; 1 MET = 3.5 ml/kg/min), we are said to be sedentary. On average, we spend 50–60% of our day sedentary and as we get older we tend to become even more sedentary.
Being sedentary for too long associates with higher risk for heart disease and premature death. Studies have revealed that that in those of us meeting the current physical activity recommendations, deleterious effects of prolonged sedentary behavior still persist, and that sedentary behavior is a risk factor for heart disease independent of physical activity. However, a study published in the Lancet, which included over 1 million individuals, showed that the risk of premature death that is associated with prolonged sedentary behavior could be eliminated with high levels of physical activity (double the current physical activity recommendation). However, majority of many national populations do not do enough physical activity to meet the recommendation, so asking them to perform twice the recommended amount of physical activity might prove difficult.
At CERG we recently developed a new metric of physical activity which we named Physical Activity Intelligence or PAI. The idea of PAI was to make it easier for people to know how much physical activity they need to do to prevent disease and premature death. PAI is a personalized reflection body’s response to physical activity and it takes into account age, sex, resting and maximum heart rate. The NTNU has now developed PAI concept into a Mio Slice wearable.
We have already shown that obtaining a 100 PAI weekly delays premature death from heart disease and all other causes, regardless of whether or not physical activity recommendations are met. However, we wanted to know if weekly PAI score of 100 could counter the negative effects of sedentary behavior on health, especially regarding the risk of heart disease.
To test this we included 29950 individuals in our study. We found that compared to most sedentary individuals but with a PAI score of 100+, individuals in the same sedentary behavior category but with a PAI score of less than 100 had higher likelihood of having clustering of risk factors for heart disease. This was true regardless of age.
Therefore, PAI could be one of the approaches used to increase physical activity participation, as it is easy to understand when one has done enough physical activity to protect one’s self as much as possible against lifestyle related diseases. Increasing physical activity participation around the world is important, as it can be a cost-effective approach to improve overall health and reduce the risk of premature death from heart disease or other causes.
Nina Zisko, Researcher at CERG