When did gyms become popular?

Gyms began to gain popularity in the late 19th and early 20th centuries, particularly with the rise of the physical culture movement. This trend was fueled by the increasing awareness of health and fitness, as well as the influence of figures like Eugen Sandow, who promoted bodybuilding. The post-World War II era saw a significant boom in gym memberships, particularly in the 1960s and 1970s, as more people embraced fitness as a lifestyle. The fitness craze continued to grow with the introduction of aerobics and health clubs in the 1980s and 1990s.