Physical inactivity is a major independent modifiable risk factor for noncommunicable diseases (NCDs) such as cardiovascular disease, ischaemic stroke, type 2 diabetes, colon cancer, and breast cancer. It is also associated with other important health outcomes including mental health, injuries, falls, and obesity.

Surveillance of population levels of physical activity using a standardized protocol is an important and necessary part of a public health response to current concerns regarding lack of physical activity in many populations. Surveillance of physical activity in populations is most often undertaken using questionnaires, as these are relatively inexpensive and easy to administer compared to objective measurement techniques, but where resources allow objective physical activity measurement is also advised.

Given the increased global interest in the role of physical activity to prevent NCDs and the lack of data to inform within-country public health efforts, the WHO developed the Global physical activity questionnaire (GPAQ) for physical activity surveillance back in 2002. Since then, the GPAQ has undergone a research programme which shows that it is valid and reliable, but also adaptable to incorporate cultural and other differences. It has been used in more than 100 countries globally, mainly through the WHO STEPwise approach to NCD risk factor surveillance (STEPS).

The GPAQ covers several components of physical activity, such as intensity, duration, and frequency, and it assesses three domains in which physical activity is performed (occupational physical activity, transport-related physical activity, and physical activity during discretionary or leisure time). It is advised that show cards be used when the GPAQ is administered. Show cards should be developed for each of the activity types covered by the GPAQ: vigorous and moderate activity at work, transport activity, vigorous and moderate activity during leisure time, as well as sitting. Show cards will help the respondents to know what activities are meant by each question and should be adapted to the local context.

Common objective measures of physical activity include devices such as accelerometers (activity watches), pedometers (step-counters), or global positioning system (GPS) units.

Measurements of physical activity with accelerometers or pedometers can be integrated in Step 2 of a STEPS survey or similar population-based survey. These measurements are generally done with a sub-sample, or ideally the entire sample of the survey, whereby each participant should wear the device over a few days. Please refer to the STEPS optional module on objective measurement of physical activity for more information.