The fact that the decline of the human functional capacity is determined by behaviors and exposures to health risks across the whole, gives physical activity (PA) and the concept of the active life style an important role. In monitoring the PA through the adult population health surveillance (quantity of PA) of the older population, there are many kinds of self-reported questionnaires such as the International Physical Activity Questionnaire (IPAQ) and General Physical Activity Questionnaire (GPAQ), which are suitable and acceptable instruments according to the World Health Organization (WHO) for those below the age of 65. Understanding the PA surveillance of older adults (> 65 years), with the exception of a few studies, also examined our institute within the framework of the PANGeA project. In 2013, we monitored the quantity of PA with GPAQ in three Slovenian towns using a sample of 445 subjects [women N = 284 (64 %), age 66.9 ± 5.1 years, men N = 161 (36 %), age 68.4 ± 5.6 years]. The comprehensive revision of the questionnaires and participants alike was carried out at the end of a day where mass measurements were taken. The results showed that only 22.6 % of participants were able to understand and fill in data properly. Furthermore, corrections were required more often in the case of the women’s data (80.1 % of the women’s data compared to 72.7 % of the men’s data). Almost a half (49.4 %) of the PA data required correction in more than one area. Fewer corrections were necessary in the case of subjects with a higher level of education. No age related differences were evident between the group requiring corrections and the group where no corrections were needed. The results indicate a need for caution in the assessment of PA in such surveys of the elderly population to ensure data correctness and to avoid the unreliability and incomparability of the data
