More and more of us in the Western world are sleep deprived. And that doesn’t mean just tired. According to WebMD, the average adult requires 7 to 8 hours of sleep per night for optimal rest. And contrary to what some may think, the body doesn’t “adapt” to less sleep, but will experience symptoms of sleep deprivation including impaired judgement and reaction time, memory loss, depression, a weakend immune system and greater sensitivity to pain (WebMD, 2015).
A 2013 Gallop Poll revealed that 40% of Americans are getting less than the recommended 7 hours per night. Sleep deprivation is such a problem in the US, that the Centers for Disease Control and Prevention (CDC) have declared it a public health problem. According to the CDC, insufficient sleep is linked to motor vehicle crashes, industrial disasters, and medical and other occupational errors (CDC, 2015). The results of sleep deprivation that may contribute to these hazardous conditions include unintentionally falling asleep, nodding off while driving, and having difficulty performing daily tasks because of sleepiness (CDC, 2015). Chronic sleep insufficiency has also been linked to other chronic diseases hypertension, diabetes, depression, and obesity and people that are chronically sleep deprived show higher rates of cancer, increased mortality, and reduced quality of life and productivity (CDC, 2015).
According to the National Sleep Foundation, humans are part of the minority of mammalian species in nature that don’t sleep for short periods throughout the day – but divide our days into two distinct periods of sleep and wakefulness (National Sleep Foundation, 2015). But it isn’t clear if this is our natural sleep pattern, in many non-Western cultures napping is an important and fixed part of life and in the US it is accepted for children and the elderly to regularly nap (National Sleep Foundation, 2015).
Now, a new study is revealing even more benefits of napping, besides just the relief from chronic sleep deprivation (as if that weren’t enough!). The study led by researchers from the University of Geneva, published in the journal eLife, show that memories associated with a reward are reinforced by sleep. Even a short nap after a period of learning is beneficial to increased retention (ScienceDaily, 2015).
In the study, researchers assigned 31 healthy volunteers to either a sleep group or a ‘wake’ group, randomly. The sensitivity of both groups to reward was assessed as being equal. Researchers scanned the brains of participants’ brains while they were trained to remember pairs of pictures. Researchers then provided a 90-minute break of either sleep or rest, and then tested participants on their memory of the picture pairs and their confidence on their answers. Overall, the sleep group performed better and were more confident in their answers (ScienceDaily, 2015). The MRI scans also showed greater activity in the hippocampus within the sleep group, the area of the brain responsible for forming memories.
How might this new research impact Western culture? If performance is the goal, then shouldn’t work and study need to be well fueled by sleep?