[ti:Study: Students Who Slept Less Struggled More in School] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.04]American high school students [00:02.24]who slept less than seven hours [00:04.84]each night during the pandemic [00:07.08]were more likely to struggle in school. [00:10.92]That finding comes from a recent study [00:13.88]from the U.S. Centers [00:15.44]for Disease Control and Prevention, or CDC. [00:20.60]The American Academy of Sleep Medicine [00:23.60]recommends that teenagers – [00:25.88]people between the ages of 13 to 19 -- [00:29.28]should sleep 8 to 10 hours a night. [00:33.96]For the study, the CDC questioned 7,705 students [00:39.88]about their sleep schedules [00:42.08]and success in school. [00:44.48]More than two-thirds of students [00:47.48]said they experienced more difficulty [00:50.44]in their schoolwork [00:51.56]during the pandemic than before the pandemic. [00:55.00]About 75 percent of students [00:58.12]did not sleep enough [00:59.60]during the pandemic, the study found. [01:03.20]"Students who experienced short sleep duration [01:07.12]were more likely to report greater difficulty [01:10.28]doing schoolwork [01:11.40]during the pandemic than before the pandemic," [01:14.80]the CDC said. [01:16.80]Duration is the length of time that something lasts. [01:21.96]Students who reported poor mental health [01:24.68]during the pandemic [01:26.04]were also more likely to get less sleep. [01:29.68]Overall, 37 percent of students [01:33.36]said they struggled with their mental health [01:36.48]during the pandemic. [01:38.12]But about 50 percent of students [01:41.00]who slept five hours or less each night [01:43.92]said they had poor mental health. [01:47.80]As students recover from learning loss [01:50.56]due to the pandemic, [01:52.04]schools "can consider including policies [01:55.28]and practices known to improve [01:57.96]sleep duration," the CDC said. [02:01.96]Teenagers experience many physical changes [02:06.12]when they go through puberty. [02:09.28]Puberty also can cause changes in sleep patterns. [02:15.20]As children get older, [02:17.24]there is a change in their circadian rhythms – [02:20.96]the body's natural clock. [02:24.12]Before puberty, children may feel sleepy [02:27.84]around 8 or 9 at night. [02:31.20]But when they get become teenagers, [02:34.72]the body's clock changes [02:37.08]to make them tired much later -- [02:40.12]around 10 or 11 at night. [02:44.36]Because of this, [02:45.84]many teenagers may experience [02:48.64]insomnia, or an inability to sleep. [02:54.04]A 2020 study published in the journal Nature [02:58.68]found that a consistent sleep schedule [03:02.16]can improve test performance. [03:05.96]Students who consistently [03:08.36]had good quality sleep [03:10.52]were much more likely to do better on tests. [03:15.60]However, "there was no relation [03:19.00]between sleep measures on the single night [03:22.28]before a test and test performance," [03:26.00]the study found. [03:28.56]Instead, sleep length and quality [03:32.64]"for the month and the week before a test [03:35.76]correlated with better grades." [03:39.28]The study looked at 100 college students. [03:43.52]However, the study's lead writer [03:46.52]said the results could be applied [03:49.16]to younger students as well. [03:52.84]Some school systems around the U.S. [03:56.20]are pushing back start times for high schools [04:00.00]so students can get more sleep. [04:04.08]Usually, high schools start the earliest [04:07.76]compared to middle and elementary schools. [04:11.32]The National Center for Education Statistics [04:15.64]says the average start time [04:18.08]for U.S. high schools is 8 a.m. [04:22.48]But the American Academy of Pediatrics [04:26.12]recommends a start time of 8:30. [04:29.72]The organization Start School Later [04:33.60]supports pushing back school start times. [04:37.56]It says at least 13,000 school systems [04:42.04]in the United States [04:43.72]have pushed back start times. [04:47.56]In 2022, California became the first state [04:53.12]to require 8 a.m. start times [04:56.48]for middle schools [04:58.04]and 8:30 a.m. start times for high schools. [05:02.84]The Lower Merion School district [05:05.56]outside Philadelphia, Pennsylvania, [05:08.28]recently voted to move [05:10.04]the high school start time from 7:30 am to 8:40 a.m. [05:15.16]The change will take effect in 2024. [05:19.68]In Howard County, Maryland, [05:21.48]the school board decided last month [05:24.16]to move the high school start time to 8 a.m. [05:27.60]starting next school year. [05:29.68]Most high schools in the county [05:32.36]now begin at 7:25 a.m. [05:36.72]"We have taken a...significant step [05:38.92]in the right direction [05:40.32]to follow the science, [05:42.00]to do what's best for students," [05:44.44]Howard County board Chair Antonia Watts [05:47.60]said after last month's vote. [05:50.76]She said it took two years of discussions [05:53.68]to make the change. [05:56.20]Some parents argue that if school starts later, [05:59.76]there will be less time for after-school activities. [06:03.64]The parents say a later start time [06:06.44]would affect their own schedule. [06:08.52]A July 2022 survey by the Sleep Foundation [06:13.12]found that a little over one-third of parents [06:16.48]supported later start times for schools. [06:20.68]The California Teachers Association (CTA) [06:25.04]opposed the state requirement. [06:27.32]The group argued that even with later start times, [06:31.20]students would still need to be dropped off [06:33.80]at school at the same time. [06:36.68]The time change, it said, [06:38.44]would especially hurt working-class families. [06:42.52]A CTA spokesperson told the Los Angeles Times, [06:46.76]"there is not enough funding from the state [06:49.40]for before school programs [06:51.48]to ensure the safety of students [06:53.92]who will be dropped off early." [06:55.68]I'm Dan Novak. [06:57.60]And I'm Caty Weaver. 更多听力请访问51VOA.COM