【英语时差8,16】早产性睡眠窒息（在线收听）

Everyone knows that caffeine keeps a person up all night. But for some people, caffeine is the doctor’s order for good, or the better word may be “safe,” sleep. Sleep apnea, a sleep disorder in which a person’s breathing periodically stops for brief periods of time, is particularly common among infants born before thirty-four weeks of pregnancy. The part of the brain that controls breathing is not yet fully mature in these infants. The result of these pauses in their breathing is sometimes a lowering of oxygen levels in their blood, leading to problems such as a bluish tint to the skin and a decrease in heart rate. For these reasons, premature infants are routinely hooked up to machines that monitor their breathing. If a baby’s episodes of apnea become frequent, a common treatment is caffeine. The popular morning stimulant stimulates the respiratory center of the infant’s brain, and the pauses in breathing decrease. As premature infants mature, they usually outgrow sleep apnea on their own.