Objective, the aim is an analysis of sociodemographic factors that had an essential relation with undertaking leisure-time physical activity—LTPA (with particular emphasis on World Health Organization (WHO) health recommendations) by adult Poles from a time-trend perspective. Methods, the paper is based on data retrieved from five large-scale surveys carried out on the representative samples of Poles aged 15–69 in 2014–2018 (n = 7347). In each wave, the Polish long version of the International Physical Activity Questionnaire was used. Results, the participation of Poles in LTPA constantly increases (p < 0.001) and the percentage of people meeting the dose of PA required for health recommendations is growing (on average, met by 43.9% of Polish men and 43.5% of women), which indicates a trend of behaviour of citizens of this country. The probability of realisation of WHO norms was determined by sex, age, place of residence and occupational status. Conclusion: it seems reasonable to develop Polish recommendations and guidelines for specific groups, including females and males, those who live in the villages and in the towns, different age groups: children/adolescents, adults (aged 50 to 59—most vulnerable to physical inactivity), the elderly, and various professional groups (especially farmers and physical workers).