Physical activity remains one of the most important factors affecting the well-being, health, and quality of life of individuals and entire populations. Unfortunately, the level of physical activity in many social groups is still insufficient according to the recommendations of the World Health Organization (WHO) and other international and national scientific societies. This paper presents the most important aspects related to the impact of physical activity on health, including lifestyle diseases, such as cardiovascular diseases, diabetes or obesity, mental health, and sleep, and overall mortality. We aimed to determine the level of physical activity in the Polish population compared with that of other European countries and in connection with guidelines and recommendations developed by various scientific societies. The most frequently reported obstacles to physical activity were also identified, and possible ways to solve these problems were discussed. Brief reference was also made to the recent COVID-19 pandemic, which had a significant impact on physical activity. We concluded that the current situation is not optimal, both in terms of implementing recommendations and guidelines for physical activity among people who are healthy and who have disease and identifying and overcoming existing barriers and limitations. We aimed to review recent trends in physical activity in Poland and the rest of Europe and discusses the potential impact of lack of physical activity on health.