Prevalence of Poor Sleep Quality and its Association with Lifestyle Habits, Competition-Based Activities, and Psychological Distress in Japanese Student-Athletes During the COVID-19 Pandemic.

Objectives The present study clarified the prevalence of poor sleep quality and its relation to lifestyle habits, competitive-based activities, and psychological distress among Japanese student-athletes in the initial pandemic period (2020) and 1 year later (2021). Methods In the present study, student-athletes were defined as individuals belonging to university athletic clubs. The data of two cross-sectional surveys (2020: n = 961 and 2021: n = 711) were collected from student-athletes in 6 universities in Japan. First, the prevalence of poor sleep quality (Pittsburgh sleep quality index score > 5) was investigated. Relationships between poor sleep quality and lifestyle habits, competition-based activities, and psychological distress were then explored using multivariate logistic regression analysis adjusted for age, sex, and body mass index. Results The prevalence of poor sleep quality was 33.6% in 2020 and 36.6% in 2021. Poor sleep quality in 2020 was related to late bedtime, taking supplements before bed, part-time job (no late night), stressors of expectations and pressure from others, and psychological distress, whereas that in 2021 was related to early wake-up time, skipping breakfast, taking caffeinated drinks before bed, use of smartphone/cellphone after lights out, stressors of motivation loss, and psychological distress. Conclusions In both 2020 and 2021, one-third of student-athletes had poor sleep quality and psychological distress was its common risk factor. Lifestyle habits and competition stressors associated with poor sleep quality were pandemic-specific in 2020, but similar to the prepandemic period in 2021.

Sleep disorder risk factors among student athletes.

OBJECTIVE: To clarify sleep disorder risk factors among student athletes, this study examined the relationship between lifestyle habits, competition activities, psychological distress, and sleep disorders. METHODS: Student athletes (N = 906; male: 70.1%; average age: 19.1 ± 0.8 years) in five university sports departments from four Japanese regions were targeted for analysis. Survey items were attributes (age, gender, and body mass index), sleep disorders (recorded through the Pittsburgh Sleep Quality Index), lifestyle habits (bedtime, wake-up time, smoking, drinking alcohol, meals, part-time jobs, and use of electronics after lights out), competition activities (activity contents and competition stressors), and psychological distress (recorded through the K6 scale). The relation between lifestyle habits, competition activities, psychological distress, and sleep disorders was explored using logistic regression analysis. RESULTS: Results of multivariate logistic regression analysis with attributes as adjustment variables showed that "bedtime," "wake-up time," "psychological distress," "part-time jobs," "smartphone/cellphone use after lights out," "morning practices," and "motivation loss stressors," were risk factors that were independently related to sleep disorders. CONCLUSIONS: Sleep disorders among student athletes are related to lifestyle habits such as late bedtime, early wake-up time, late night part-time jobs, and use of smartphones/cellphones after lights out; psychological distress; and competition activities such as morning practices and motivation loss stressors related to competition. Therefore, this study suggests the importance of improving these lifestyle habits, mental health, and competition activities.

The protective effect of lycopene intake on bone loss in ovariectomized rats.

Antioxidant lycopene supplementation has been shown to decrease oxidative stress and have beneficial effects on bone health. However, it remains unclear whether lycopene exerts its beneficial effect on bone metabolism through mitigation of oxidative stress in vivo. The aim of this study was to investigate whether lycopene intake protects against bone loss by reducing oxidative stress in ovariectomized rats. Female Sprague-Dawley 6-week-old rats were ovariectomized and randomly divided into four groups according to the lycopene content of their diet: 0, 50, 100, and 200 ppm. The tibial bone mineral density (BMD) in the 50, 100, and 200 ppm groups was significantly higher than that in the 0 ppm group. Serum and urinary bone resorption marker levels were significantly lower in the 50, 100, and 200 ppm groups than in the 0 ppm group. There was no significant difference in systemic oxidative stress markers among all groups. However, systemic oxidative stress levels were inversely correlated with the tibial BMD. Our findings suggest that lycopene intake significantly inhibits bone loss by suppressing bone resorption in ovariectomized rats. Further studies are necessary to clarify the effect of lycopene on oxidative stress in local tissues such as bone tissue.

Lycopene intake facilitates the increase of bone mineral density in growing female rats.

Intake of the antioxidant lycopene has been reported to decrease oxidative stress and have beneficial effects on bone health. However, few in vivo studies have addressed these beneficial effects in growing female rodents or young women. The aim of this study was to investigate the effect of lycopene intake on bone metabolism through circulating oxidative stress in growing female rats. Six-week-old Sprague-Dawley female rats were randomly divided into 3 groups according to the lycopene content in their diet: 0, 50, and 100 ppm. The bone mineral density (BMD) of the lumbar spine and the tibial proximal metaphysis increased with lycopene content in a dose-dependent manner; the BMD in 100 ppm group was significantly higher than in the 0 ppm group. The urine deoxypyridinoline concentrations were significantly lower in the 50 and 100 ppm groups than in the 0 ppm group, and the serum bone-type alkaline phosphatase activity was significantly higher in 100 ppm group than in the 0 ppm group. No difference in systemic oxidative stress level was observed; however, the oxidative stress level inversely correlated with the tibial BMD. Our findings suggested that lycopene intake facilitates bone formation and inhibits bone resorption, leading to an increase of BMD in growing female rats.

Hydrolyzed collagen intake increases bone mass of growing rats trained with running exercise.

BACKGROUND: Some studies have shown that dietary hydrolyzed collagen peptides (HC) effectively prevent age-related bone loss. However, it is not known whether the intake of HC also has positive effect on bone mass or strength when combined with exercise during growth phase. METHODS: We examined the effects of 11 weeks of HC intake and running exercise on bone mass and strength in growing rats. Rats were randomized into four groups, the 20% casein group (Casein20), the 40% casein group (Casein40), the 20% HC group (HC20), and the 40% HC group (HC40). Each group was further divided into exercise groups (Casein20 + Ex, Casein40 + Ex, HC20 + Ex, HC40 + Ex) and non-exercise group (Casein20, Casein40, HC20, HC40). In the HC intake groups, 30% of casein protein was replaced with HC. Exercise group rats were trained 6 days per week on a treadmill (25-30 m/min, 60 min) for 60 days. After being sacrificed, their bone mineral content (BMC) and bone strength were evaluated. RESULTS: Exercise and dietary HC effects were observed in the adjusted BMC of lumbar spine and tibia among the 20% protein groups (p < 0.001 for exercise; p < 0.05 for dietary HC, respectively). These effects were also noted in the adjusted wet weight and dry weight of femur among the 20% protein groups (p < 0.001, p < 0.01 for exercise; p < 0.01, p < 0.001 for dietary HC, respectively). On the other hand, in adjusted bone breaking force and energy, dietary HC effect was not significant. Among the 40% protein groups, similar results were obtained in the adjusted BMC, femoral weight, bone breaking force, and energy. There were no differences between the 20% protein groups and the 40% protein groups. CONCLUSIONS: The present study demonstrated that moderate HC intake (where the diet contains 20% protein, of which 30% is HC) increased bone mass during growth period and further promoted the effect of running exercise. On the other hand, a higher HC intake (where the diet contains 40% protein, of which 30% is HC) had no more beneficial effect on bone mass than the moderate HC intake.

Effect of different intake levels of dietary protein and physical exercise on bone mineral density and bone strength in growing male rats.

Having higher bone mineral density (BMD) during growth is complexly influenced by many factors. For example, nutrition and physical exercise are key factors. However, few studies have investigated the combined effects of these factors. In this study, we investigated the effect of physical exercise and different levels of protein intake on BMD and bone strength of growing male rats. Forty-seven male Wistar rats (5 wk old) were randomized into 10% (Low), 20% (Moderate) and 40% (High) protein diet groups, and each group was further divided into exercise groups (LEx, MEx, HEx) or non-exercise groups (L, M, H). Exercise group rats were trained 6 d per week on a treadmill (25-30 m/min, 60 min) for 60 d. After being sacrificed, their BMD and bone strength were evaluated. The BMD of tibia, femoral breaking force and energy were significantly lower in the low protein diet groups than the other diet groups. In particular, the femoral breaking energy was significantly lower in the HEx group than in the H group, while there were no differences between LEx and L or MEx and M. Taken together, our data suggests that a low protein intake could suppress acquisition of bone mass and increasing bone strength during growth. Moreover, a high protein intake could also suppress bone strength during growth in which physical activity was vigorously performed. Therefore, sustaining an adequate protein intake level, around 20% protein intake, may be of significance for increasing not only bone mass but bone strength during growth.