A Case for Unifying Accelerometry-Derived Movement Behaviors and Tests of Exercise Capacity for the Assessment of Relative Physical Activity Intensity

Albert Einstein taught us that everything is relative. People's experience of physical activity (PA) is no different, with relativism particularly pertinent to the perception of intensity. Markers of absolute and relative intensities of PA have different but complimentary utilities, with absolute intensity considered best for PA guideline adherence and relative intensity for personalized exercise prescription. Under the paradigm of exercise and PA as medicine, our Technical Note proposes a method of synchronizing accelerometry with the incremental shuttle walking test to facilitate description of the intensity of the free-living PA profile in absolute and relative terms. Our approach is able to generate and distinguish can do or cannot do (based on exercise capacity) and does do or does not do (based on relative intensity PA) classifications in a chronic respiratory disease population, facilitating the selection of potential appropriate individually tailored interventions. By synchronizing direct assessments of exercise capacity and PA, clearer insights into the intensity of PA performed during everyday life can be gleaned. We believe the next steps are as follows: (1) to determine the feasibility and effectiveness of using relative and absolute intensities in combination to personalize the approach, (2) to determine its sensitivity to change following interventions (eg, exercise-based rehabilitation), and (3) to explore the use of this approach in healthier populations and in other long-term conditions.

Automated summary

Albert Einstein's theory of relativity applies to the perception of intensity in physical activity (PA). Absolute and relative intensity markers have different utilities, with absolute intensity being more suitable for PA guideline adherence and relative intensity for personalized exercise prescription. This study proposes a method of synchronizing accelerometry with the incremental shuttle walking test to describe the intensity of free-living PA in absolute and relative terms, which can help classify exercise capacity and relative intensity in a chronic respiratory disease population and facilitate individually tailored interventions.