The researchers gave participants a genetic saliva test to determine which type of coffee metabolizer they were.

研究人员给参与者做了基因唾液测试，以确定他们是哪种类型的咖啡代谢者。

In fact, the slow caffeine metabolizers, on average, had almost an hour less sleep when they were exposed to coffee.

事实上，咖啡因缓慢代谢者喝咖啡时，平均睡眠时间少了近一个小时。

But the results varied a lot from person to person depending on whether they were fast or slow coffee metabolizers — which is determined by your genetics.

但每个人的结果相差巨大，而这取决于他们是快速还是缓慢的咖啡代谢者——这是由你的遗传决定的。