The relationship between sleep, perfectionistic strivings, perfectionistic concerns, and academic and sports performance in young athletes.

Perfectionism is associated with sleep as well as with academic and sports performance. Given the importance of sleep for performance and the sleep changes that occur during adolescence, the present study aimed to explore the relationship between sleep, two dimensions of perfectionism (perfectionistic strivings and perfectionistic concerns), with academic and sports performance in young athletes. The occurrence of perfectionistic strivings was identified as a tendency to set high personal standards for oneself, while the occurrence of perfectionistic concerns was identified as a tendency to feel pressure to be perfect and have concerns about imperfections. A total of 32 athletes aged 13 to 16 years old participated in this study. Perfectionism, sleep, and course grades were measured at the end of the school year. Sleep was measured by actigraphy, and sports performance improvement was obtained by comparing individual performance at the beginning and the end of the school year. The moderating effect of both dimensions of perfectionism on the relationships between sleep and academic and sports performance improvement was measured. First, results showed no significant relationship between sleep and academic/sports performance. Further analyses revealed that perfectionistic strivings moderated the relationship between certain aspects of sleep with academic and sports performance improvement. Delayed and suboptimal sleep habits were associated with lower academic and sports performance improvement when low levels of perfectionistic strivings were present. Results with perfectionistic concerns showed that this dimension did not moderate the relationship between sleep and academic and sports performance improvement. This study supports the notion that high levels of perfectionistic strivings in young athletes may mitigate the adverse effects of poor sleep habits in young athletes.

Greater circadian disadvantage during evening games for the National Basketball Association (NBA), National Hockey League (NHL) and National Football League (NFL) teams travelling westward.

We investigated the effects of a circadian disadvantage (i.e. playing in a different time zone) on the winning percentages in three major sport leagues in North America: the National Basketball Association, the National Hockey League and the National Football League. We reviewed 5 years of regular season games in the National Basketball Association, National Hockey League and National Football League, and noted the winning percentage of the visiting team depending on the direction of travel (west, east, and same time zone) and game time (day and evening games). T-tests and analysis of variance were performed to evaluate the effects of the circadian disadvantage, its direction, the number of time zones travelled, and the game time on winning percentages in each major league. The results showed an association between the winning percentages and the number of time zones traveled for the away evening games, with a clear disadvantage for the teams travelling westward. There was a significant difference in the teams' winning percentages depending on the travelling direction in the National Basketball Association (F2,5908  = 16.12, P < 0.0001) and the National Hockey League (F2,5639  = 4.48, P = 0.011), and a trend was found in the National Football League (F2,1279  = 2.86, P = 0.058). The effect of the circadian disadvantage transcends the type of sport and needs to be addressed for greater equity among the western and eastern teams in professional sports. These results also highlight the importance of circadian rhythms in sport performance and athletic competitions.

Estrogen-like endocrine disrupting chemicals affecting puberty in humans--a review.

Estrogen-like endocrine disrupting chemicals (EEDC) are exogenous, man-made chemicals that alter the functions of the endocrine system and cause various health defects by interfering with the synthesis, metabolism, binding or cellular responses of natural estrogens. EEDCs have been found in various plastic products, flame retardants, pesticides and many other products that are needed for daily use. Some of the greatest effects of EEDCs are on puberty, a period of rapid physiological changes like growth spurt, maturation of the gonads and the brain. Estrogen, one of the key hormones required in puberty is crucial for the sexual differentiation. The structural similarity of estrogen disruptors with estrogen allow them to bind and activate estrogen receptors and show a similar response even in the absence of estrogen that can lead to precocious puberty (PP). Major EEDCs found abundantly in our environment include; dichlorodiphenyltrichloroethane (DDT), dioxin, polychlorinated biphenyls (PCBs), bisphenol A (BPA), polybrominated biphenyls (PBB), phthalate esters, endosulfan, atrazine and zeranol. In girls, DDT has been linked to earlier menarche. Dioxin causes abnormal breast development in pre-pubertal girls. BPA has shown to cause PP in pubertal girls. PBB causes earlier menarche, thelarche and earlier pubic hair stage in pubertal girls. PCB's showed a significant delay in puberty in pubertal boys. De-feminization, thelarche, or early secondary breast development are shown in pubertal girls when exposed to phthalate esters. Endosulfan affects pubertal boys by slowing down the timing of reproductive maturation. This article provides a possible structure-function relation of the above mentioned EEDCs which interfere with sexual development during puberty.