Relationships Between Depression And Sleepiness, Daily Physical Activity Level, Physical Fitness In Japanese University Student

Abstract

PURPOSE: Life style has been disturbed in recent Japan, particularly in young generation, which may deteriorate quality and quantity of sleep and decrease physical activity. In addition, depressive tendency has been becoming widespread in college age. Therefore, it is important to examine the relationships among those factors. In this study, we report significant correlations between depression and sleepiness, daily-physical-activity-level, physical fitness in Japanese university student. METHODS: Eighty-five undergraduate students participated in this study (52 men and 33 women). We measured physical activity level using an accelerometer (Lifecorder [Lc], Kenz, Nagoya, Japan) for 2 weeks. The Lc measured the daily number of steps (steps per day), 24-energy expenditure (kJ per day), and energy expenditure of exercise (kJ per day). To evaluate the level of endurance fitness, Maximal oxygen uptake (VO2max) was calculated by an indirect method using a cycle ergometer. The VO2max was predicted by the nomogram of Åstrand and Ryhming, a modality that is generally used to predict the VO2max. Depressive tendency and daytime sleepiness was evaluated with questionnaire, PHQ9 and JESS (Japanese version of the Epworth Sleepiness Scale), respectively. RESULTS: The mean of PHQ9 score, sleepiness score, the number of steps, and VO2max were 5.3 ± 3.3, 10.7 ± 3.6, 9513.3 ± 3283.2 steps, and 42.5 ± 6.5 ml/kg/min., respectively. There were significant positive correlations between PHQ9 score and sleepiness, PHQ9 score and physical activity variables (N = 85; r = 0.35 and r = 0.39, respectively; p < 0.05 for both). That was also true between PHQ9 score and VO2max. (r = 0.25; p < 0.05). The trends were more pronounced in male than in female. CONCLUSIONS: Our important finding is that there are positive correlations between depression and variables of physical activity level. The mean values of daily physical activity level of participants with depression tendency were within normal range. Then we infer that sports facilities or sports-oriented club activities with fierce competition, especially in male students, may cause both high daily-physical-activity-level and depressive tendency in university students.