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From VOA Learning English, this is the Health Report. Do you often start your day feeling tired? Do you ever fall asleep at work? Do you sometime feel “out of it” — as if your brain is still asleep even though your body is awake?
If you answered “yes” to any of these questions, you might be suffering from what some researchers call “social jet lag.” Till Roenneberg is a German chronobiologist, a scientist who studies how living things adapt to and are governed by periods of time, such as lunar or solar cycles. Mr. Roenneberg says that many people are working at times that do not match their body’s natural sleep-wake cycle. This natural cycle is called the circadian rhythm. Mr. Roenneberg says when your work schedule conflicts with your body’s inner clock it can lead to extreme tiredness, similar to “jet-lag”. With jet lag, people feel extremely tired when they travel long distances in a short period of time by air. Till Roenneberg led researchers in a study at Ludwig-Maximilian University in Munich, Germany. They studied “social jet lag” among workers at a steel company in Europe. Factory workers were given work times that matched their natural sleeping habits. Changing the workers’ schedules to fit their lifestyle made them feel more rested and improved their sense of wellbeing, says Mr. Roenneberg. But the people who worked at night did not report the same level of improvement. Mr. Roenneberg adds that employees who wake after better rest are more productive. The journal Current Biology published the study.