Time in the United States is later than China, 13-18 hours ahead of the United States in China Standard Time East 8, for example, respectively.

China is a vast country, spanning five time zones east to west, namely East 5, East 6, East 7, East 8 and East 9 time zones. The United States across the West 5 to West 10, *** six time zones, from east to west were West 5 (Atlantic coast and near the continent of the 19 states and Washington, D.C., the representative city of Washington, West 6 (Chicago and New Orleans two areas), West 7 (Mountain), West 8 (four states along the Pacific coast, with cities such as Los Angeles), West 9 (Alaska) and West 10 (Hawaii).

The impact of time difference:

People in the corresponding time zone in the long-term adaptation caused by the human body's physiological rhythms and the local synchronization of the alternation of day and night, the human body's adaptability that is known as the body's biological clock.

The human body after the formation of this "like circadian rhythm activity", that is, in sleep, wakefulness, body temperature, urination, diet and other aspects of the performance of the periodic rhythm or habit, the normal alternation of work capacity and sleep state, in order to adapt to the day and night changes.

And modern air travel, in a relatively short period of time can cross a number of time zones, this change beyond the body's ability to regulate physiological rhythms, thus causing physiological rhythm disorder. The main symptom is a feeling of intense fatigue such as: not awake, drowsy, fatigue, reduced work efficiency; second, loss of appetite, due to jet lag reasons to change the original meal time, thus appearing changes in gastrointestinal function, loss of appetite, indigestion, and other symptoms; third, sleep disorders such as: difficult to fall asleep, wake up early, sleep is not real; fourth is to disrupt the original habits of defecation, appear constipation or diarrhea.

In order to reduce the impact of crossing the time zone on the body's physiological rhythm, first of all, we must correctly recognize this phenomenon, in the long distance across the meridian flight should try to get sleep to reduce the effect of jet lag, to eat less high-fat food and alcoholic beverages. After arriving at the destination, rest l-2 days before starting work.

Reference: Baidu Encyclopedia - Jet Lag, Baidu Encyclopedia - United States, Baidu Encyclopedia - Beijing Time