Remember the 1980s anti-drug campaign with the guy in the kitchen who held a frying pan (“This is your brain.”) and an egg (“This is drugs.”)? And then he cracked open and fried the egg and said, “This is your brain on drugs.”
Well, in many ways, that egg could just as easily represent the sleep-deprived state many of us inhabit every day. Like every other organ and cell in the body, the brain needs sleep to thrive. We’ve all experienced the brain fog that follows a night of poor slumber — hopefully for most, brain fog was the worst of it. Neuroscientists are intensely studying how chronic sleep loss impacts brain function. You won’t want to lose any more sleep after reading this.
The effects of sleep deprivation have vast implications on psychological, physical and social health, plus occupational well-being and driving safety. Total sleep deprivation (24-plus hours of being awake) can cause significant impairments in attention, memory and mood, with lesser effects on motor skills and complex tasks. The impact of chronic partial sleep loss — what most of us experience on a regular basis — has received far less attention.
Attention is the cognitive ability most easily influenced by sleep deprivation. As the day wears on, deficits in attention increase and your ability to focus on tasks becomes erratic — not good for procrastinating teens who save up homework and test cramming for the last waking minute. Memory behaves in a similar manner, as does the brain’s reward system, which controls motivational behaviors like risk-taking and impulsivity. Sleep loss impairs rational decision making when we’re challenged with making difficult choices.
A great example of this involves desirable foods and illustrates key connections between the brain and gut. Studies suggest that sleep deprivation is associated with increased hunger and cravings for high-calorie, high-carb foods, such as fast-food and sweets. Lack of sleep increases gherlin, a hunger-controlling hormone, while decreasing leptin, an appetite-suppressing hormone — ultimately leading you to cave and devour the chocolate cake waiting patiently in your refrigerator. Getting regular adequate sleep can get your diet back on track.
One of the most striking cognitive consequences of sleep loss is impaired driving. The 2014 American Automobile Association Traffic Safety Culture Index showed that 96% of drivers considered it unacceptable for someone to drive when they’re so exhausted that they have a hard time keeping their eyes open. Yet, a whopping 29% had done just that in the prior 30 days. Another AAA study found a drowsy driver was involved in 13% of non-fatal crashes resulting in hospital admission and 21% of fatal crashes. Most drowsy driving accidents occur between 2 to 6 a.m. and 2 to 4 p.m., as well as after driving continuously for more than two hours. Younger drivers have the greatest risk.
We’re finding out more about the neurophysiological underpinnings of impairments in cognition, alertness and mood associated with sleep loss. Sleep deprivation produces changes in brain cells that interrupt communication between other cells in the brain. In the hippocampus, part of the brain that plays a crucial role in memory consolidation, this effect on brain cell synapses damages the transfer of short-term memory into long-term memory. Interestingly, the hippocampus is one of the first structures to become impaired in patients with Alzheimer’s disease, the most common cause of dementia. Further, disturbed sleep seems to be a precursor to memory loss in many AD cases. Researchers are now designing studies aimed to address these early sleep disorder symptoms in hopes of preventing dementia.
Sleep is not the idle, death-like state that scientists thought for centuries. Rather, sleep is an active process that restores and revitalizes the brain and body. One of the most fascinating recent illustrations of this was the discovery that beta-amyloid plaque — the toxic substance that accumulates in the brain leading to Alzheimer’s disease — and sleep duration in older adults are inversely correlated (less sleep, more plaque). Similarly, in the sleeping brains of mice, metabolic waste products like beta-amyloid are cleared at a faster rate than during wakefulness. Both studies support the notion that the restorative function of sleep may be caused, in part, by the removal of neurotoxins that build up during waking hours, similar to the accumulation of sleep debt that begins from the moment we arise in the morning until we hit the sack at night.
Sleep loss is similar to being drunk. Beyond sleep deprivation, prolonged wakefulness is associated with potentially devastating effects on brain function and performance. In one classic experiment, researchers found decreased performance on an attention and motor skills task after 17 hours of being awake equivalent to having a blood alcohol level of 0.05%, over the legal level of intoxication in most industrialized countries. This is roughly the spot where many of us are after a long day at the office.
[See: 8 Steps to Fall Asleep Fast.]
Sleep needs vary by age and are genetically determined. The National Sleep Foundation’s sleep recommendations call for seven to nine hours in adults, eight to 10 in older teens, nine to 11 in school aged children and up to 14 in toddlers. Most of us know someone — and maybe it’s you — who is seriously sleep deprived. So get some shut-eye; your brain will thank you for it.
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