Sedentary time, physical activity and cardiometabolic health. Accelerometry-based study in the Northern Finland Birth Cohort 1966

A PhD thesis performed at the University of Oulu showed that limiting the duration of sedentary time (sitting or lying) to 15–30 minutes by breaking them frequently with any physical activity may be beneficial for cardiometabolic health in middle-aged adults. Importantly, the study shows that the interruptions in sedentary time could be short and performed with either light or brisk physical activity activities, convenient walking for instance.

Indeed, the study also shows that replacing even 10 minutes of daily time spent in sedentary with either light or brisk physical activity have several beneficial effects on cardiometabolic health in adults. The beneficial effects could be seen for many cardiometabolic health markers including insulin level, blood lipid and glucose, and body mass index.

The thesis by MSc Vahid Farrahi, carried out at the University of Oulu and the ODL Department of Sports and Exercise Medicine, was part of the Northern Finland birth cohort 1966 program consisting of 5,840 participants, who underwent a clinical examination and completed an extensive set of questionnaires at the age of 46 years. Physical activity and sedentary time were measured with an acceleration-based activity monitor for a period of two weeks. The study was funded by the EU H2020 MSCA COFUND and the Ministry of Education and Culture, Finland.

“It is encouraging especially for those who are most inactive, that they can improve their cardiometabolic health simply by frequently breaking their sedentary bouts and increasing a little bit their overall light physical activity. After all, the physical activity recommendations are quite difficult for many”, says Farrahi.

Cardiometabolic diseases are among the leading causes of deaths. All daily movements behaviors, including sedentary behaviors (activities in sitting, lying, and reclining posture with minimal energy expenditure), and light-intensity (such as shopping and walking) and moderate-to-vigorous (such as skiing and running) physical activity may be related to cardiometabolic health. Although physical activity recommendations encourage adults to engage in 150-300 minutes of moderate-to-vigorous-intensity physical activity per week, many adults fail to meet the current recommendations and spend most of their daily time in sedentary. According to this study, in addition to moderate-to-vigorous physical activity, adults may also gain cardiometabolic health benefits through light-intensity physical activities, particularly when it replaces sedentary time.

In recent years, wearable activity monitor technologies have advanced, allowing for precise monitoring of all daily activities, even the short-lasting sporadic movements. More recently, machine learning approaches, a sub-field of artificial intelligence, have emerged in the field of physical activity to address complex analytical challenges. This thesis used machine learning approaches for improved accuracy in the measurement of physical activity behaviors from wearable activity monitors, and to create activity profiles for participants.