It's fashionable at the moment because what's been shown is that within the brain, a whole raft of genes have been shown to be turned on only during sleep, and those genes are associated with restoration and metabolic pathways.
当时流行的原因是 人们发现只有在睡眠时, 大脑内部的很多基因才会活动起来， 而且这些基因与修复 和新陈代谢的途径相关联。