Physical Activity, Sedentary Behavior, and Body Image among Young Adults in Hong Kong: A Cross-Sectional Study

The COVID-19 pandemic has considerably impacted the health and lifestyle of various populations worldwide, leading to decreased physical activity, increased sedentary behavior, and increased health problems. This study aimed to investigate Hong Kong young adults’ physical activity, related behaviors, and perceptions of body image during the pandemic. A cross-sectional online survey of young adults aged 18–29 was conducted from February to March 2021 using the well-validated Multidimensional Body Self-Relations Questionnaire (MBSRQ). Among 408 respondents, 52.5% had a normal weight in the BMI range, 45.1% engaged in ≥8 h of sedentary behavior daily, 77.2% engaged in no regular or inadequate physical activity (<2.5 h/week), and only 22.3% joined a fitness club. BMI, regular physical activity, and joining any fitness club/class were significantly associated with the most factors or additional subscales. A multiple linear regression model showed that the underweight respondents (reference group: normal) (β = −0.26, 95% CI: −0.41 to −0.12) were less likely to have high scores of fitness orientation. The respondents who engaged in regular physical activity <2.5 h/week (β = 0.42, 95% CI: 0.29 to 0.54), engaged in regular physical activity ≥2.5 h/week (β = 0.99, 95% CI: 0.84 to 1.14) (reference group: no regular physical activity), and joined a fitness club/class (β = 0.32, 95% CI: 0.18 to 0.45) were more likely to have a high score of fitness orientation. Local governments, non-governmental organizations, schools, and community centers should establish appropriate strategies and activities in order to sufficiently encourage and support young adults’ physical health and well-being.