英语翻译［1］If you are worried about things and are under a lot o

英语翻译
［1］If you are worried about things and are under a lot of stress at work or school,then you are prob-ably not sleeping well.Worry can keep you awake,tossing and turning in bed until the early hours of the morning when you eventually fall asleep.When you wake up,you don't feel refreshed,but tired and worn out and unable to face a new day.［2］ Dr.Henry Winkle,in a recent newspaper article entitled Stress and Sleep,indicates that .Dr.Winkle says,“The more we worry,the less we sleep,the more we are unable to deal with stress.If we can find a way to get a good night's sleep,”he adds,“we can often find the energy to deal with what's worrying us.” ［3］So,what is a good night's sleep?Research shows that the amount of sleep which people need in order to keep healthy varies a lot.Seven hours is about the average amount,though strangely enough,sleeping longer often gives you a headache instead of making you feel more refreshed.［4］Dr.Winkle believes that preparing for sleeping is important.People who work late should try to give themselves a short break and do something restful before going to bed.This could be watching TV or listening to music.Doing some exercise earlier in the day should help you to feel physically as well as mentally tired.A bedtime drink can also help,but coffee or tea should be avoided as they contain caffeine and will keep you awake.［5］ “When you put the light out,” Dr.Winkle says,“concentrate on relaxing your muscles,working slowly up from your feet,and you 'll be asleep before you know it.”
What does the word “it” (Line2,Paragraph5) probably refer to?

[1]在工作中或是在学校学校,如果你担心着事情并因此承受着很大的压力,你就有可能睡不好觉.你会因为担心保持清醒,在床上辗转反侧,直到次日清晨你才会最终入睡.当你醒来,你不会感觉到恢复精神,除了累和疲惫不堪,及无法面对新的一天.[2] Henry Winkle（人名）博士在最近的一份报纸上的一篇题为“压力和睡眠”,表明 .Winkle博士说:“我们愈担心,我们就愈少睡眠,就愈多的无法应付压力.如果我们能找到一个办法让我们好好睡一觉,”他补充说,“我们就能够经常找到能对付困扰我们的能量.“[3]所以,什么是好好睡一觉呢?研究表明,就是人们需要为了保持健康大量变化的睡眠量.七个小时是平均睡眠量,但奇怪的是,久睡经常是让你头痛而不是让你感觉更舒畅.[4] Winkle博士相信,准备睡觉是很重要的.经常工作很晚的人应该试着给自己一个短暂的休息,去做一些上床睡觉之前感到安静的事.这可以是看电视或听音乐.在当天早些时候做一些锻炼应该帮助你感觉到自己的身体以及精神都疲劳.睡前喝东西也有帮助,但咖啡或茶应该避免,因为它们都含有咖啡因能使人保持清醒.[5]“当你把灯关了,”Winkle博士说,“集中精力放松你的肌肉,做慢慢地从你的脚上往上提升活动,你就会在不知不觉中睡着了.”
问题：单词“it（它）”(Line2,Paragraph5（在第五段第二行中)）可能指什么?
再问： 我是问这个it指代什么？