From London buses to activity trackers: A reflection of 70 years of physical activity research

In 1953, Morris et al. published their ground-breaking findings among London bus drivers and conductors, linking physical activity to a major chronic disease for the first time. This seminal paper marked the birth of a new field—physical activity epidemiology. Since then, the field has flourished, evidenced by mounting scientific publications. Our knowledge about the role of physical activity in disease prevention has expanded from coronary heart disease in Morris et al.’s initial study to dozens of additional diseases and conditions, such as diabetes, cancers, and dementia. More than 7 decades and thousands of publications later, we critically reflect on several aspects of the progress in physical activity epidemiology.