What's your usual sleeping pattern? If you're happily tucked up in bed by 8 pm or even earlier, then you might have what's known as advanced sleep phase (ASP).
你习惯什么睡眠模式？如果你晚上8点或者更早就开开心心地上床睡觉了，那你可能患上了睡眠状态提前综合征。
It's a sleep pattern that's traditionally been considered incredibly rare – after all, these so-called 'advanced sleepers' are naturally waking up at around 4 or 5 am, totally rested.
这是一种睡眠模式，历来被认为非常罕见，毕竟这种所谓“提前入睡者”在早上四五点左右会自然醒来，完全清醒了。
But a new study of 2,422 people attending sleep clinics in the US has hypothesised that number might be much higher.
但对进入美国睡眠诊所的2,422人进行的一项新研究猜测患者人数可能更多。
ASP leads to a shift in the body's circadian rhythm, which means the sleep-inducing hormone melatonin is produced by the brain much earlier in the evening than for other people. That's matched with a drop in body temperature.
睡眠状态提前综合征会导致身体昼夜节律发生变化，也就是说患者在夜间大脑促进睡眠的褪黑激素的分泌要比其他人早得多，同时伴随体温降低。
The sleep study found that eight of the 2,422 participants they observed over nine years displayed ASP – that's around 0.33 percent, and far more than experts expected.
睡眠研究发现他们在九年里观察的2,422人中有八人患有睡眠状态提前综合征，比例约为0.33%，比专家预测得多得多。
Of the eight patients that the researchers identified as having ASP, five had close family members with the same sleeping pattern, suggesting that this is something that runs in the family – and may have a genetic basis.
研究人员确认患有睡眠状态提前综合征的八名患者中，有五人的家人有相同的睡眠模式，表明这是家族遗传的，而且可能是基因决定的。
Further genetic testing found two of the relatives had genetic mutations linked to familial advanced sleep phase (FASP).
进一步的基因测试发现两个亲戚有与睡眠状态提前综合征有关的基因突变。
These advanced sleepers are more easily able to get up in the morning, and average a measly 5-10 minutes extra lie-in on non-work days, as opposed to the 30-38 minutes the rest of us average when we don't have to get up to start a shift.
这些提前睡觉的人早上起床更容易，非工作日平均只多休息5-10分钟，而不是像我们其他人一样不需要早起上班时会平均多休息30-38分钟。
One reason that ASP and FASP numbers might have been underestimated, the researchers suggest, is that people don't bother to report it or get treatment for it – they just live their lives waking up early and going to bed early.
研究人员表示，睡眠状态提前综合征患者人数没有得到足够重视的一个原因就是人们不必报告或进行治疗，他们只是过着早起早睡的生活。