Sleep is an important part of our lives. We spend about one-third of our lives sleeping. For millions of people,【51】, getting enough sleep is a continuing struggle. A recent study found that thirty-five percent of Americans have【52】going to sleep or staying asleep. The problem is called insomnia. Insomnia exists【53】a person is not able to get the【54】of sleep needed to operate effectively. Insomnia is not【55】in numbers of hours of sleep. This is because different people need【56】amounts of sleep to feel rested. The most common problems【57】from insomnia are sleepiness and trouble in completing work. Other problems are emotional disorders and difficulty【58】thinking. The treatments for【59】 were discussed at a recent meeting of the Association of Professional Sleep Societies. The group's sleep experts say there are three kinds of insomnia. One【60】is called transient insomnia. It【61】just a few days. It is a result of moderate tension. The tension can be caused by a long airplane flight or a brief stay in a hospital.【62】kind is called short-term insomnia. It lasts several weeks and results from more【63】tension. The tension may be caused by problems at work or at home, a major sickness or the death of a loved one. The third kind of insomnia is called【64】. It lasts longer than several weeks. It often is a sign of severe physical or【65】problems. Sleep experts say anyone with long-term insomnia should be examined so the cause can be found and treated. Many things we eat or drink can affect our【66】. Drinks containing alcohol or caffeine can block sleep.【67】can some medicines. Other causes of insomnia include breathing problems or sudden, uncontrolled body movements during sleep. Because insomnia has so many causes, not all treatments are【68】for everyone. But experts have offered some simple ideas that work for most people. If【69】to sleep, they say, get up and go to another room, if possible. Stay up until you are really【70】, them return to bed. Get up at the same time every day. Do not exercise just before going to bed. And, do not worry about past problems or future plans. (51)