This was during the first deep sleep period, the researchers said.

研究人员说，这发生在第一次深度睡眠期间。

youdao

Acute insomnia means consistent inability to sleep well for a period of three weeks to six months.

严重失眠意味着连续三周到六个月都睡不好觉。

youdao

It usually happens in the first few hours of sleep in the period called deep sleep.

它通常发生在睡眠的最初几个小时，这个阶段被称为深度睡眠阶段。

youdao

When it was very, very hot in the middle of the day there was not point in being out, and you could actually use that period to get some sleep so you needed less sleep at night.

BBC: How we go to sleep

"When people are entering a high-stress period, they don't sleep and don't exercise, but in fact, it should be just the opposite, " says Loehr.

FORBES: How To Run On Fumes

Vacations have been found to help us recharge -- we sleep better during them and for a period of time afterwards.

CNN: Take your vacation, or die?