Feeling tired is just one tiny part of it.
The National Sleep Foundation recommends that adults get at least seven hours of sleep per night, and according to the 2014 Sleep Health Index, people are, on average, clocking in just enough, at seven hours and 36 minutes per night. Still, the CDC deems insufficient sleep a "public health epidemic," and despite the positive effects of rest, 42 percent of Americans still report fewer than seven hours of sleep per night. Not convinced that you need a full seven hours? Here's the latest consequence: Losing sleep may worsen memory and make recall more stressful.
The findings will be published in the journal SLEEP, and suggest that sleep is essential in ensuring proper function of memory recall, especially in times of stress. Researchers from Uppsala University in Sweden compared subjects who got eight hours of sleep to those who only had four, and found that the latter were not able to recall previously learned card pair locations without feeling stressed. Plus, the shortened sleep cycle reduced their recall abilities by 10 percent due to acute levels of stress experienced right after waking up. Those who slept a full night weren't stressed when asked to recall the card pairs.
"Interventions such as delaying school start times and greater use of flexible work schedules, that increase available snooze time for those who are on habitual short sleep, may improve their academic and occupational performance by ensuring optimal access to memories under stressful conditions," lead researcher Jonathan Cedernaes said in a statement.
This isn't the first time sleep has been linked to memory performance. Earlier research from Brandeis University showed something similar—all-nighters don't seem to be effective, because the brain needs sleep in order to convert short-term memories into long-term. And because sleep affects your ability to focus and concentrate, skimping on it impairs learning (and if you didn't learn something correctly in the first place, it's certainly hard to remember it). In the long-term, sleep loss has been linked to buildup of Alzheimer's disease, and may contribute to memory loss.
Treat yourself to an early bedtime—you won't regret it.