Findings
There is a wide variability in PA measurement methodologies in existing literature, which complicates comparisons across studies.
The use of digital tools like activity monitors complicates the regulatory process due to non-interchangeability and varying technical and regulatory requirements.
There is a need for standardized procedures to ensure data comparability and integrity.

Recommendations
Implement a standardized methodology for PA data collection and reporting.
Use a standard operating procedure for data collection regarding PA outcomes.
Ensure that activity monitors meet safety, usability, and acceptability criteria for COPD patients.
Encourage widespread adoption of the proposed recommendations to facilitate further research.
Consider device agnosticism while ensuring device sensitivity and accuracy.

Regulatory Considerations
Devices should be device agnostic but must ensure sensitivity, accuracy, and data verification.
Regulatory requirements vary across jurisdictions and need to be met for device approval.
Safety, usability, and acceptability of devices for COPD patients are critical criteria.