1.Tired? We all know the feeling. Irritable, groggy, and exceptionally lazy. Chances are, you didn't sleep enough last night. Or the past few nights.
Chances are:同於It's likely that...，表示某事可能發生
2.But what exactly is enough sleep? And, more importantly, can you ever catch up on it?
catch up on:補償（睡眠）
3.While the very fuction of sleep is still debated by scientists, we do know that it's necessary to function efficiently and productively. After all, we spend 24 years of our lifetime sleeping. It had better be important.
4.Researchers have tested how much is required each night by assigning groups of people to four, six, and eight hours of sleep over extended periods of time.
5.After 14 days, those with eight hours of sleep exhibited few attention lapses or cognitive issues. However, those with six or four hours of sleep showed a steady decline.
- to debate the pros and cons of a situation 討論某情況的利與弊
- a lapse of memory 記錯
- a lapse in concentration 走神
6.In fact, after only two weeks, the six hour group showed a similar reaction time to a person with the blood alcohol concentration of 0.1%, which is considered legally drunk.
7.The four hour sleepers suffered even more, occasionally falling asleep during their cognitive test.
- cognitive theory/science 認知理論/科學
8.In both groups, brain function decreased day-by-day almost linearly, with no sign of leveling off. Scientists have dubbed this cumulative effect as sleep debt.
9.However, with long term sleep deprivation,on the scale of weeks to months, the recovery of cognitive function is much slower, requiring many more nights of quality sleep.
10.Paradoxically, with chronic sleep deprivation, your sleepiness or how tired you feel does eventually level off, meaning that you become less and less aware of your objective impairment over time.
- mental/physical/visual impairment 智力低下/身體損傷/視力損傷
- impairment of hearing 聽力損傷
Most studies tend to show that 7-8 hours of sleep is the average ideal for humans. Apart from the cognitive issues, individuals who consistently sleep less than seven hours a night have an increased risk of heart disease, obesity and diabetes. Not to mention, a 12% higher risk of death.
On the flip side, studies have shown that while sleeping more than eight hours does not impair brain function, it also carries an increased risk of heart disease, obesity, and diabetes, and a 30% increased risk of mortality. So too much sleep may also be a bad thing.
On the flip side:反面