BACKGROUND：Physical activity （PA） is low and or absent among young women. We focused on the potential of “watching” professional baseball games to promote PA among young women. OBJECTIVES：This study aimed to 1） examine the relationship between watching professional baseball games and PA among young women, and 2） the motivations and interests leading to higher PA levels among those who watch these games. METHODS：A web-based questionnaire survey was conducted from June 7 to 13, 2022, targeting young women （aged 20-34 years）. The responses were obtained from 200 participants each of who did and did not watch the baseball games in the past year. The International Physical Activity Questionnaire-Short Version （IPAQ-SV） was assessed whether or not the total PA was ≥150 minutes/week. The spectator engagement was assessed for hedonic （entertainment, centrality, and solidarity） and self-expressive factors （symbolism and place attachment）. RESULTS：The proportion of respondents with total PA of ≥150 minutes/week was 27.5% of spectators and 16.5% of non-spectators. As per a Poisson regression model adjusting for potential confounders, spectators were more likely to meet the criteria for total PA （PR = 1.66, 95% CI: 1.13-2.43） compared with non-spectators. Moreover, the participants with higher entertainment, solidarity, and place attachment factors were more likely to have longer total PA compared with those without these factors. CONCLUSION：Young women who experience watching professional baseball games tend to engage in longer total PA. Those with higher levels of entertainment, solidarity, and stadium attachment tended to have longer total PA.

Prevention of pneumonia is important because pneumonia is one of the major causes of death in older adults. Furthermore, disuse syndrome due to pneumonia may cause frailty or disability in older adults during their hospitalization. Influenza and COVID-19 vaccination has been recommended for older adults to prevent serious complications （e.g., pneumonia） and death because they are high-risk individuals for influenza and COVID-19 infections. Prevention of pneumonia by influenza and COVID-19 vaccination is important for older adults to extend their healthy life expectancy.