[Impact of evening exercise on college students' sleep quality]

To investigate the impact of college students' evening exercise on their sleep quality, so as to provide a scientific basis for college students to choose an appropriate method of exercise and improve their sleep quality.

From September to October in 2012, Multi-stage cluster random sampling method was used to select the 5997 college students in Anhui province. The status of college students' exercise and their sleep quality were investigated by the general situation questionnaire, Physical activity rating scale-3(PARS-3), Rating of perceived exertion(RPE) and Pittsburgh sleep quality index(PSQI). Kruskal-Wallis test was used to analyze the impact of evening exercise on sleep quality and multivariate unconditional logistic regression was used to analyze the factors of sleep quality in evening excise students.

The median of PSQI total score among 5806 college students was 5 and 1030(17.7%) students had poor sleep quality. The median of the PSQI scores was the same (5 points) for evening exercise group, daytime exercise group,daytime and evening exercise group and non-exercise group (1406, 1514, 1244, 1642 respectively). The difference was not statistically significant (χ(2) = 2.80, P = 0.42). Compared to non-exercise population, the OR (95%CI) value of evening exercise' impact on sleep quality was 0.90(0.73-1.10). Compared to very light evening exercise, the OR (95%CI) value of moderate and large amount of evening exercise' impact on sleep quality was 0.58 (0.44-0.75) and 0.67 (0.48-0.93) respectively; Compared to other sports, the OR (95%CI) value of badminton, rope skipping and jogging' impact on sleep quality was 0.72 (0.55-0.93), 0.38 (0.21-0.70) and 0.76 (0.60-0.95) respectively and they were all protective factors of sleep quality. Compared to small exercise intensity, the OR (95%CI) value of moderate, vigorous and very vigorous exercise intensity' impact on sleep quality was 1.68 (1.13-2.52), 2.38 (1.48-3.83) and 3.18 (1.72-5.90) respectively and they were harmful factors of sleep quality.

There was no impact of evening exercise on sleep quality for college students. Type of sports should be adequately chosen for evening exercise. College students can take moderate and large amount of evening exercise but should avoid activities of vigorous intensity.