Impact of COVID-19 Pandemic Lockdown on Body Mass Index and Physical Fitness in Chinese College Students

Purpose To explore the impact of COVID-19 pandemic lockdown (CoPL) on body mass index (BMI) and physical fitness among college students. Methods Two one-year cohorts, one with no pandemic lockdown (NoPL) exposure and one with CoPL exposure, were included. Baseline measurements were performed in October 2018 (NoPL) and October 2019 (CoPL), and follow-up data were collected one year later. Participants were divided into “deterioration”, “no-change”, and “improvement” groups based on their quartile distribution of one-year differences (follow-up–baseline) for lower 25%, middle 50%, and upper 25%. Baseline-category logit regression models were used to determine the odds ratios of deterioration and improvement in BMI and physical fitness, with “no-change” used as baseline. Results A total of 2,594 and 2,525 students were included in NoPL and CoPL cohorts, respectively. CoPL was associated with higher odds for deterioration in BMI (male), explosive strength, upper-limb muscle strength, abdominal muscle strength, and cardiorespiratory fitness, but lower odds for deterioration in BMI (female) and flexibility. CoPL was associated with lower odds for improvement in BMI (male), explosive strength, lower-limb and upper-limb muscle strength, and cardiorespiratory fitness, but higher odds for improvement in BMI (female) and flexibility. Discussion Not all dimensions of health outcomes were negatively impacted by the lockdown, as deterioration in BMI in males, muscle strength, and cardiorespiratory fitness following the CoPL were more than that in the absence of the lockdown, while deterioration in BMI in females and flexibility were less than that in the absence of the lockdown.