Novel Input for Designing Patient-Tailored Pulmonary Rehabilitation: Telemonitoring Physical Activity as a Vital Sign—SMARTREAB Study

Physical inactivity may be a consequence of chronic diseases but also a potential modifiable risk factor. Therefore, it should be clinically assessed as a vital sign of patients’ general physical condition prior to any exercise-based intervention. This cross-sectional study describes physical activity in the daily life of 100 chronic respiratory patients before pulmonary rehabilitation, comparing subjective and objective measures. The assessment combined the International Physical Activity Questionnaire (IPAQ) and 4-day accelerometer and oximeter telemonitoring with SMARTREAB technology, assessing heart rate, transcutaneous oxygen saturation and activity-related energy expenditure by metabolic equivalent of task (MET). According to IPAQ, 49% of patients had a moderate level of physical activity in daily life (PADL), a weekly mean level of 2844 ± 2925 MET.min/week, and a mean sedentary time of 5.8 ± 2.7 h/day. Alongside this, SMARTREAB telemonitoring assessed maximum activity ranging from 1.51 to 4.64 METs, with 99.6% daytime spent on PADL below 3 METs and 93% of patients with daily desaturation episodes. Regardless of the self-reported IPAQ, patients spend at least 70% of daytime on PADL below 2 METs. SMARTREAB was demonstrated to be an innovative methodology to measure PADL as a vital sign, combining oximetry with accelerometry, crossmatched with qualitative patient data, providing important input for designing patient-tailored pulmonary rehabilitation.