THE SLEEP CURE
(Original article by Alice Park, in TIME Health Feb 16, 2017)
The evidence linking quality rest to good health and longevity has never been more convincing, especially as it relates to aging, processing emotions, mental health, and disease prevention.
Scientists are learning that shortchanging sleep can compromise nearly every major body system, from the brain to the heart to the immune system, making our inability–or unwillingness–to sleep enough one of the unhealthiest things we can do.
Studies of people whose sleep sessions are irregular or shorter than seven hours show they are at higher risk of developing diseases that can lead to early death, including heart disease, cancer, diabetes, high blood pressure and obesity. Poor sleep may have detrimental effects on the brain as well, increasing the risk of dementia, including Alzheimer’s disease, as well as mood disorders like depression, posttraumatic stress disorder (PTSD) and anxiety. And like smoking, a terrible diet and not exercising enough, poor sleep is now linked to an overall increased risk of premature death.
“I used to suggest that sleep is the third pillar of good health, along with diet and exercise,” says Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley. “But I don’t agree with that anymore. Sleep is the single most effective thing you can do to reset your brain and body for health.”
Despite the mounting evidence of its benefits, Americans are sleeping about two hours less each night than they did a century ago, and while life expectancy has been inching upward over the past century thanks to advances in medicine and technology, those gains could start to sag under the weight of our collective sleeplessness. Many people still dismiss sleep as something they can occasionally (or even regularly) skimp on.
Perhaps that’s because until very recently, scientists couldn’t even agree on the evolutionary reason why animals need to sleep in the first place. But now they know that what happens during sleep, particularly in the brain, is critical to human well-being–not to mention a long life.
Spending a good third of the day oblivious to the world around you and, by extension, incapable of protecting yourself doesn’t seem like a smart way for a species to stay alive. And yet every animal does it, leading scientists to accept that sleep must be nonnegotiable for some reason–and that we must need a certain amount of it to survive.
Following a rigorous, milestone study in 2002 of more than 1 million healthy men and women by the American Cancer Society, experts found that people who slept seven hours per night were most likely to still be alive at the end of the study’s six years, compared with people who got either six hours or less, or eight hours or more, of sleep each night. To this day, seven hours is typically the amount that doctors and public-health groups recommend for the average adult.
Another even longer study, which followed more than 21,000 twins in Finland, found that people who were regularly sleeping less than seven hours daily were 21% to 26% more likely to die of any cause during the study’s 22-year period than those who slept more than eight hours.
So clearly sleep has some real biological benefit. Could it just be that the brain and body need downtime to recuperate after the activity of the day? That was the most popular explanation for decades, until an inquisitive neuroscientist at the University of Rochester decided to look for the answer inside the brain itself. When she did, Dr. Maiken Nedergaard uncovered what many scientists now agree is sleep’s primary evolutionary function: to clean out the brain, quite literally, of accumulating debris.
In 2014, Nedergaard first revealed that while the body appears to rest during sleep, a whole lot is happening inside the brain. Neurons pulse with electrical signals that wash over the brain in a rhythmic flow. The brain runs checks on itself to ensure that the balance of hormones, enzymes and proteins isn’t too far off-kilter. All the while, brain cells contract, opening up the spaces between them so that fluid can wash out the toxic detritus that can cause all kinds of problems if it builds up.
“It’s like a dishwasher that keeps flushing through to wash the dirt away,” Nedergaard says.
Without that nightly wash cycle, dangerous toxins can damage healthy cells and interfere with their ability to communicate with one another. In the short term, that can impede memory formation and the ability to coherently compose our thoughts and regulate our emotions. Over time, the consequences can be more dire. Lack of sleep can lead to faster aging of brain cells, contributing to diseases like Alzheimer’s, which is now the cause of death for 1 in 3 seniors.
“Sleep is not just a passive state but a fairly active state on the molecular level,” says Dr. Allan Pack, director of the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania. “During the day, the brain is using energy resources to fire neurons. At night, a switch turns on so the sleeping brain can take advantage of the metabolic downtime to do some cleaning up.”
The idea that sleep is a time of important biological activity, rather than a period when the body checks out, is transforming how doctors think about another important factor in longevity: mental health.
Scientists have long known that sleep is important for memory. But it turns out that during sleep, especially the cycles of deep dream sleep, the brain doesn’t just revisit the events of a day in a more organized way. It also works on processing the emotions attached to these recollections. When a memory is filed away during sleep, it’s also stripped of some of the powerful feelings–like fear, grief, anger or joy–that might have clouded the experiences in the heat of the moment.
It wouldn’t be healthy, or efficient, to remember every event or experience in its full factual and emotional context. But separating the emotional aspects of a memory from its objective parts allows you to recall the experience without reliving it. “We sleep to remember and we sleep to forget,” says Walker, the UC Berkeley sleep scientist, of this coping mechanism. “I call it overnight therapy.”
This type of processing takes time. It likely happens only during deep, quality sleep, and only over consistent nights of such sleep. That may explain why people who cut their sleep short or experience interrupted sleep may not fully disentangle the emotional baggage from their memories.
In those cases the memory, in its emotionally taxing entirety, continues to resurface every time the brain tries to sleep, in a vain effort to be properly processed. The brain tries to store the memory in a neutral way, but without deep sleep, there just isn’t enough time for that triage.
Walker believes these aborted efforts may drive conditions like PTSD, which is well understood to be common among combat veterans but which may be more common among the general population than therapists and researchers previously thought.
“The more nights you sleep, the more soothing the influence of sleep on that memory,” he says. “Sleep continues to work on those emotional memories and flatten them out after about a week. Now there’s great evidence that PTSD is a disorder in which that process fails.”
There’s also strong support for the idea that insufficient sleep may be a trigger for, and not just a symptom of, a number of mental illnesses, including depression, bipolar disorder, and even schizophrenia. Depriving people with bipolar disorder of sleep, for example, can launch a manic episode, while some people with depression report worsening symptoms when they aren’t sleeping well.
Fully understanding the role sleep plays in mental illness is a rich area of future research. Already many doctors think consistent, high-quality sleep can have a direct bearing on the health of those with mental illness. “Anyone who suffers from moderate or significant mental-health concerns needs to be aware that sleep may be one of the most important things they can do,” says Walker.
Stress, scientists also know, is one of the more potent accelerators of aging, and a body that’s not sleeping enough looks similar to one that’s stressed out–it’s highly reactive to perceived threats, even when those threats don’t pose any real risk. Biologically speaking, both stress and lack of sleep have the same result: fight-or-flight mode is triggered, blood pressure spikes, breathing gets shallow, and the heart starts to race.
Those stress reactions would be useful if you needed to react to a physical threat, but that’s not usually what’s going on. And staying in an alert mode can trigger a number of unhealthy conditions, the most damaging of which is inflammation.
Inflammation is the body’s natural defense system against injury or invading microbes like bacteria and viruses. It’s why your toe turns red and throbs when you stub it or when it’s infected: white blood cells rush to the area in order to protect it for the short time it’s needed to help you get better. But inflammation can also become chronic, and that’s when the real trouble starts.
Chronic inflammation, doctors now know, is a leading driver of many diseases, including some cancers, cognitive decline, heart disease, Type 2 diabetes–even chronic pain. And one of the main drivers of chronic inflammation is, of course, not sleeping enough.
Experts are insisting, with increasing frequency and noise, that sleep be a priority–as important or more than what you eat and how much you exercise. We wouldn’t dream of skipping meals on a regular basis, so why skimp on sleep?
The full article can be found on Time.com, click here: The Sleep Cure