For most people this comprises roughly 40-60% of total sleep time.

对于大多数人来说， 这大约占总睡眠时间的 40-60%。

He said, " Our study suggests that there is a middle range, or 'sweet spot, ' for total sleep time" for best cognitive performance.

" 我们的研究表明，最佳认知表现对应的总睡眠时间存在一个中间区间，即‘最佳点’" 。

Monday's study from Eastern Virginia Medical School in Norfolk covered 1,000 people and found that total sleep time decreased as body mass index, a measure of weight based on height increased.

周一，位于美国弗吉尼亚州诺福克市的东维吉尼亚医学院发布了这份研究。对1000名受试者的研究显示累计睡眠时间和体重指数刚好成反比，体重指数是一种以身高为基准来衡量体重的方法。