- 2019Sep 18
*The following is excerpted from an online article posted on ScienceDaily.
Adolescents with higher levels of physical activity performed better in school during transition from primary school to lower secondary school than their physically inactive peers, a new study from Finland shows. However, the researchers, from the University of Jyväskylä, found that increased physical activity did not necessarily result in improved academic performance.
Previous cross-sectional studies have reported that physically more active children and adolescents achieve better school grades than their less active peers do, but there are few longitudinal studies on the topic. A newly published study showed that adolescents with higher levels of physical activity over a follow-up period of two academic years had higher academic performance than did those who were continuously inactive. Furthermore, the study showed that increased levels of physical activity do not automatically result in improved academic performance. Instead, the results suggest that those adolescents who increased their physical activity had lower academic performance during the follow-up compared to their more active peers.
What the results mean
Highly active adolescents performed better in school compared to their less active peers. However, our results showed that increasing physical activity over a period of two academic years did not necessarily improve academic performance.
What the results do not mean
Based on our results, it is not possible to say whether physical activity improves academic performance or if adolescents with higher academic performance choose a physically active lifestyle. Therefore, no causal interpretations can be made. However, the results of the present study do not refute the findings of previous studies showing small but positive effects of physical activity on learning and its neural underpinnings.
- 2019Sep 17
*The following is excerpted from an online article posted on National Institutes of Health.
Teen girls — but not boys — who prefer to go to bed later are more likely to gain weight, compared to same-age girls who go to bed earlier, suggests a study funded by the National Institutes of Health. The findings by researchers at Kaiser Permanente in Oakland, California, and other institutions appear in JAMA Pediatrics.
A total of 804 adolescents (418 girls and 386 boys) ages 11 to 16 took part in the study. The children responded to questionnaires on their sleep habits and wore an actigraph — a wrist device that tracks movement. Researchers measured their waist size and calculated their proportion of body fat. They also estimated the children’s social jet lag — the difference between their weeknight and weekend bedtimes. Those who stayed up far later on weekends than weeknights were considered to have high social jet lag. The authors noted that previous studies had found that adults who preferred to stay up late and had high social jet lag were more likely to gain weight than those who went to be earlier and did not have social jet lag. The researchers undertook the current study to determine if the same associations would be seen in young people.
For girls, staying up later was associated with increases in waist size and body fat. Each hour of social jet lag was associated with a 1.19 cm larger waste size and a 0.45 kg/m2increase in body fat. These associations were reduced—but still remained—after the researchers statistically adjusted for other factors known to influence weight, such as sleep duration, diet, physical activity and television viewing. Although the researchers found slight associations between these measures and waist size and body fat in boys, they were not statistically significant. The researchers concluded that improving sleep schedules may be helpful in preventing obesity in childhood and adolescence, especially in girls.
Source: National Institutes of Health
- 2019Sep 16
*The following is excerpted from an online article posted on HealthDay.
Teens who spend more time with social media are more likely to suffer from social withdrawal, anxiety or depression, a new study says.
Twelve- to 15-year-olds who spent more than six hours a day on Facebook, Instagram, Twitter and other social media were nearly three times more likely to have these types of "internalizing" mental health issues, researchers report in the journal JAMA Psychiatry.
"The more time you spent on social media, adolescents were more likely to have issues like anxiety and depression on follow-up," said lead researcher Kira Riehm, a doctoral student at Johns Hopkins Bloomberg School of Public Health in Baltimore. "It was a pretty clear-cut association."
These teens also were more than four times as likely to have both internalizing and externalizing mental health problems, researchers said. Externalizing problems include bullying, acting out and having trouble paying attention.
For the study, researchers analyzed nationwide data from a U.S. federally funded survey of nearly 6,600 teens. It was conducted between 2013 and 2016.
Fewer than 17% of teens said they used no social media, researchers found. About 32% said they spent less than 30 minutes a day on social media; 31% spent between 30 minutes and three hours; 12% spent three to six hours, and 8% said they used social media more than six hours per day.
As use increased, so did the risk of problems with anxiety, depression or feelings of isolation.
Researchers concluded that teens who spent more than three hours a day on social media could be at increased risk for mental health problems.
Other studies have found similar effects, but no one's quite sure why social media might have this impact on teenage minds, Riehm said.
It could be that social media harms a teen's self-esteem by creating the illusion that everyone else is much happier and better off, she said.