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. But what exactly is "enough sleep?" And more importantly, can you ever "catch up" on it?
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. After 14 days, those with eight hours of sleep exhibited few attention lapses of cognitive issues; however, those with six or four hours of sleep showed a steady decline. In fact, after only two weeks, the six hour group showed a similar reaction time to a person with a blood alcohol concentration of 0.1%, which is considered legally drunk.
Can we recover from it? The short answer is yes, with a few nights of good sleep. 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.
So how long should you sleep? Most studies tend to show that seven to eight 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.