Even morning coffee might mess with your sleep

A study using brain recordings suggests that caffeine may reduce deep sleep even when people fall asleep normally and sleep for eight hours. The effect may be hard to notice and varies from person to person.

一项利用脑电记录开展的研究表明，即使人们正常入睡并睡满八小时，咖啡因也可能减少深度睡眠。这种影响可能不易察觉，而且因人而异。