So one could have a very good day and test well, or one could just not be feeling one's best and test poorly.

所以，有些人可能因为这一天状态很好而取得好成绩，而有些人因为这一天状态不佳而发挥失常。

And evidence is cropping up to suggest that a poor night's sleep is not only felt the next day but could have implications for one's heart over the long term.

但证据却意外的表明一个低质量的晚觉不仅会影响第二天，同时也会在很长一段时间内对心脏造成影响。已经证实的，睡眠窒息导致的睡眠中多次呼吸的中断，和中风及冠状动脉的疾病有关。