Stepping out of time

摘要

By the time Elizabeth Klerman boards the train to go to her office at Brigham & Women's Hospital in Boston, Massachusetts, the conductor has been awake for hours, rising in the dead of night for his first train at four o'clock. This schedule is not merely demanding, but contrary to most people's circa-dian rhythms, the pattern of physiological and metabolic activity that is roughly in synchrony with the rising and setting of the Sun."Some people are trying to live and work with an abnormal relationship between their circadian rhythm and the clock," says Klerman, who studies human sleep patterns. Most of us have experienced this mismatch in the form of jetlag. For shift-workers and others with 'unnatural' routines, however, this desynchronization occurs every day and can result in chronic sleep deficits. Researchers are now trying to understand the prevalence and severity of the problem, and to devise strategies that can help reset these clocks.