The Dimensions of Sleep

Sleep restores us in stages and cycles, but some struggle to slumber

Sleep is key to mental and physical health, playing a critical role in the body's maintenance and rejuvenation cycle. (Billion Photos/Shutterstock)

Many of us have a love–hate relationship with sleep. It can be delicious when we’re exhausted. But having to sacrifice so much time just to lie there with the worries of the day circling your head until you finally, hopefully drift off can make sleep seem more like a burden.

If we manage to get the recommended eight hours a night, we devote a third of our lives to sleep. But this precious time also competes with endless temptations beckoning us to leave the lights on and stay up late.

Sleep-skimping habits start early. According to data from the U.S. Centers for Disease Control (CDC), more than two-thirds of U.S. high school students (a population that may need as much as 10 hours of sleep a night) report getting less than eight hours on school nights.

Some get much less. Copywriter Snezhina Piskova recalls that when she was a student she managed to get by on only three hours a night. A constant flow of coffee and energy drinks helped push her through the day, but her evenings were usually filled with insomnia-induced anxiety. Eventually, she suffered a terrible burnout.

“It was truly horrific,” Piskova said. “Thanks to this, however, I have learned quite a bit about maintaining proper sleep hygiene.”

Part of Piskova’s appreciation for sleep came from learning about what it does for her body. She discovered that, despite being such a sedentary activity, sleep takes care of a lot of important business.

“The body undergoes deep maintenance work, rebuilding muscles, and sorting through experiences,” she said. “These processes can only occur in such depth while we are asleep.”

Sleep is particularly beneficial to the brain. According to the National Institute of Neurological Disorders and Stroke Health with the U.S. National Institutes of Health (NIH), sleep helps you form and maintain the pathways in your brain that let you learn and create new memories. That’s why a lack of sleep makes it harder to concentrate and respond to the world around us.

Sleep also prevents disease. Research has shown that chronic sleep loss can lead to high blood pressure, diabetes, stroke, and weight gain, as well as increase our risk for certain forms of cancer and Alzheimer’s disease.

But even if you manage to devote more time to sleep, getting enough can still be elusive. According to the latest Sleep in America Poll by the National Sleep Foundation, Americans feel sleepy on average three days a week and say their mood, mental acuity, and productivity all suffer as a result. The majority (55 percent) blame the problem on poor quality sleep.

One obvious factor in keeping us awake is caffeine. According to Dr. Ivy Branin, a New York City-based naturopathic doctor who specializes in treating insomnia, caffeine blocks the release of a brain chemical called adenosine. Adenosine levels rise by the end of the day, making us feel tired. But too much caffeine too late can inhibit this response.

How much is too much, and how late is too late? That depends on you.

“The half-life of caffeine (the time it takes for half of this substance to be eliminated from the body) is typically between five and six hours, but for some people it can be as long as nine hours,” Branin said. “Levels of 100mg and above of caffeine prevent the action of adenosine to produce tiredness. So if you are someone who metabolizes caffeine slowly, the cut-off time should be in the morning, and the caffeine content should be low.”

Another factor that often interferes with sleep quality is the drugs we take to fall asleep. Branin says that alcohol and benzodiazepines (medications often prescribed for insomnia) can interfere with a deep stage of the sleep cycle called REM sleep. The acronym stands for rapid eye movement—one of the physical characteristics of this special sleep stage.

“Plus alcohol can increase cortisol release,” Branin said. “Spikes in cortisol due to alcohol will make us feel more alert, making sleep difficult.”

Rest and Regeneration

One contributing aspect to sleep loss is that we like to brag about being busy. In most social circles, there is more cultural currency in talking about how much we are doing than how much we are sleeping.

Hearing talk about how little sleep others get might make you feel lazy in comparison. But Piksova says it’s not a competition. It’s about regeneration.

“Every person is different,” Piskova said. “I myself can function at full capacity with exactly eight hours, but my friend Anna is a hyperactive ball of energy with only six hours of sleep.”

For optimal health, adults typically need between seven and nine hours of sleep per night (infants and toddlers may need as much 16 hours a night, plus naps). Only about 1 percent of the population (known as short sleepers) do well on six hours or less—a sleep schedule that would cause the rest of us problems with our mood and cognitive performance during the day. Depression, anxiety, bad judgment, not to mention feeling tired the next day, are common symptoms of sleep loss.

The reason we need to sleep as long as we do is that our brains and bodies need to cycle through three distinct sleep stages a few times per night to get fully recharged. Before we reach REM sleep, we first have to go through light and deep non-REM sleep stages, and we need to have enough of each to be rejuvenated for the next day. The duration of each stage can vary by age and individual. But according to Jason Piper, certified sleep coach and founder of Build Better Sleep, the body generally likes to prioritize deep sleep in the first half of the night, and REM in the second half.

“During deep sleep, all the good stuff of body restoration occurs. It does most of its repairs and growth during this stage also,” Piper said. “Have you ever known someone that routinely goes to bed really late, how tired and aged their face looks? That is because the repair that normally happens is shortened.”

It was once thought that dreaming only occurred in REM sleep, but recent research finds that we may dream at any stage of sleep. However, REM is when we have our most intense and vivid dreams. It may seem like we’re just lying there, but during REM, the brain is just as active as someone who is awake. Piper describes it as a firmware update for a computer.

“During this time, memories are consolidated. Short-term memories move to long term, and more abstract thinking and connections happen,” he said. “You know the saying, before making a decision, to sleep on it? That’s why. Your brain processes and analyzes it even while you are sleeping.

In general, deep sleep benefits the body, and REM the mind. But there is evidence of crossover. One 2008 study found that short sleep time is associated with overweight children and adolescents, which may be attributed to reduced REM sleep.

And it isn’t just the duration and type of sleep that matters, but also the time.

Our mind and body prefer to cycle through the deeper stages of sleep in the dark of night. Piper says those who try to accomplish this cycle during the day are forced to work against the body’s natural biological clock.

“This is not normal, nor recommended,” he said. “Those who sleep during the day do not produce the same amount of melatonin or get as much deep and REM sleep as night sleepers. This is why you will see shift workers being diagnosed with higher incidences of cancer, diabetes, and heart disease.”

In 2007, the International Agency for Research on Cancer (IARC) with the World Health Organization (WHO) published a decision based on experimental and epidemiological data stating that working the late shift is “probably carcinogenic to humans.”

Overcoming Sleep Obstacles

Once we realize the importance of getting enough sleep, how can we ensure our sleep hours are truly rejuvenating?

Since alcohol and benzodiazepines are problematic, naturopath Dr. Christian Gonzalez recommends gentle, yet effective chamomile tea as a nightcap.

“Chamomile is generally used for its calmative and sleep inducing properties,” Gonzalez said. “Its compound apigenin exerts these benefits by traveling to the brain and stimulating GABA receptors for a nervous system calming effect. This is the same target as popular benzodiazepines like Xanax, Ativan, and Valium.”

Light is another factor that can influence our sleep quality. Gonzalez says natural light and dark cycles are imperative for the balance of our biological clock.

“This helps coordinate body physiology and immune function. Unfortunately, these delicate mechanisms are easily disrupted by artificial light,” he said.

For this reason, Gonzalez recommends sleeping in the pitch black. He points to one study that shows that women who have artificial street light coming into the room were at significantly higher risk for breast cancer than those sleeping in total darkness.

“The reason for this is the disruption of the hormone melatonin, a potent antioxidant and immune stimulator against cancer cells,” Gonzalez said. “Artificial light at night disrupts normal melatonin secretion.”

Ideally, we should also distance ourselves from any light emitting devices, like cellphones and laptops, as we wind down before bed. This cuts our exposure to both light and electromagnetic frequencies—another factor that messes with our melatonin. A study conducted by The Department of Electrical and Electronic Engineering at the University of Melbourne found that EMFs may influence the pineal gland, where melatonin is produced.

“How man-made EMFs may influence the pineal gland is still unsolved. The pineal gland is likely to sense EMFs as light but, as a consequence, may decrease the melatonin production,” researchers state.

To avoid this unseen source of pineal stimulation, Gonzalez recommends sleeping with your phone in airplane mode, and kept at a distance from your body. Plus, turn the Wi-Fi off. You don’t need it when you’re sleeping anyway.

Practicing good sleep hygiene means adopting habits that help ensure a good night’s sleep. But don’t beat yourself up if it doesn’t work right away. If you’ve tried everything and still can’t sleep, clinical psychologist Jodi J DeLuca says don’t force it. Instead, find some low-light activity to occupy your mind for a little while.

“Get up, leave the bedroom, and do something that doesn’t require too much physical or mental energy, such as reading, listening to an audio book, working on a puzzle, writing in a journal, or working on a hobby,” DeLuca said.

Like eating healthy and getting enough exercise, sleep hygiene works best with consistency. The more you can make your bedroom environment and nighttime routine conducive to sleep, the more truly rejuvenative hours you’ll have each night.

“A critical component to a better night’s sleep is to make sure that your brain is conditioned to associate your bed as a place for rest and sleep,” DeLuca said. “When getting into bed, make a conscious effort to remind yourself that it’s time to power down from the mental and physical activity of the day.”