Relationships between sleep quality, physical fitness and body mass index in college freshmen

The aim of this study was to analyze the association between poor sleep quality with BMI and health-related physical fitness among college freshmen.

The participants were college freshmen enrolled in 2011. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). A global PSQI score of 5 and total sleep time (TST) of 7 hours were used to differentiate between poor and good sleepers. Various Body Mass Index (BMI) ranges were used to categorize groups of underweight, normal weight and overweight. Health-related fitness was measured by Sit-And-Reach, Curl-Up, and Run/Walk Tests.

A substantial proportion of college students were affected by poor sleep quality. Significantly more females were poor sleepers and had a TST shorter than 7 hrs. No difference in the proportions of participants categorized based on BMI between male and female students. Males generally scored better on health-related physical fitness tests than females. All results of physical fitness tests were significantly correlated with BMI, sleep quality (global PSQI), and TST in both males and females. Pool sleepers were associated with a higher BMI and lower performance of physical fitness. TST was negatively associated with BMI and time length to complete 1600-m or 800-m Run/Walk Test, and positively correlated with the performance of Sit-And-Reach and Curl-Up Tests in both genders.

Poorer sleep quality and decreased TST were associated with lower performance in health-related physical fitness assessment among college students. Health promotion and educational programs for young adults should emphasize the importance of sleep quality and TST.