By Dr. Mercola
Sleep deprivation is a well-known risk to your physical, mental, and emotional well-being. What makes sleep deprivation so detrimental is that it doesn’t just impact one aspect of your health… it impacts many.
When you’re sleep-deprived, you’re not going to react as quickly as you normally would, making driving or other potentially dangerous activities, like using power tools, risky.
Your ability to think clearly is also dampened by lack of sleep, which means you will have trouble retaining memories, processing information, and making decisions.
As your reaction time and cognition slows, your emotions will be kicked into high gear. This means that arguments with co-workers or your spouse are likely and you’re probably going to be at fault for blowing things out of proportion.
But much more than that, sleep deprivation has virtually the same effect on your immune system as physical stress or illness, which may help explain why lack of sleep is tied to an increased risk of numerous chronic diseases.
There’s an important caveat to be aware of that is not yet widely known, however, and that is your sleep quality is every bit as important as your sleep duration. So if you stay in bed for eight or nine hours a night, but during that time you’re waking up repeatedly, it’s just as bad as getting hardly any sleep at all…
One Night of Interrupted Sleep Wreaks Havoc on Your Mood, Energy Levels
Just one night of interrupted sleep is all it takes to make you feel more depressed, fatigued, and confused, according to new research.1 What’s more, there was little difference in the negative effects of interrupted sleep (defined as four prolonged awakenings spread across eight hours in bed) compared to those of restricted sleep (spending just four hours in bed, total).
Night-wakings also lead to reduced vigor and motivation and increased errors on an online performance test. The study attempted to mimic life-like night-wakings, which for the study purposes included making a phone call to participants in the middle of the night directing them to complete a brief computer exercise (at four separate occasions during the night).
It’s a scenario that may not seem unfamiliar to you, especially if you find yourself waking at night frequently. What does this mean for new parents, doctors (mostly residents in training but certain specialties like OB and trauma surgeons on ER call), and the millions of other people who find their sleep regularly interrupted at night (by pets, noise, racing thoughts, light pollution, work obligations, and more)? If you suffer from interrupted sleep, it might be putting your health at risk. Professor Avi Sadeh of Tel Aviv University, the study’s lead author, said:2
“Our study shows the impact of only one disrupted night. We know that these effects accumulate and therefore the functional price new parents — who awaken three to ten times a night for months on end — pay for common infant sleep disturbance is enormous…
I hope that our study will bring this to the attention of scientists and clinicians, who should recognize the price paid by individuals who have to endure frequent night-wakings.”
Interrupted Sleep Makes It Difficult to Get Through the Necessary Stages of Sleep
It makes sense that interruptions to your sleep would result in much the same damage as lack of sleep, because sleep occurs in phases. Ideally, you should progress from slow-wave sleep back up to REM sleep in 60- to 90-minute cycles.
Any interruptions to this make your body start over, in a sense, which means you might never reach the most restorative, deeper phases of sleep.
You might as well not be sleeping at all, which is likely one reason why lack of sleep and interrupted sleep result in such similar damage. In a healthy night’s sleep, you should progress through the following sleep stages (though not necessarily in this order):3
- Stage One, when you’re preparing to drift off
- Stage Two, during which your brain wave activity becomes rapid and rhythmic while your body temperature drops and heart rate slows
- Stage Three, when deep slow brain waves emerge (this is a transition from light sleep to deep sleep)
- Stage Four, also known as delta sleep, this is a deep sleep stage
- Stage Five, or rapid eye movement (REM) sleep, is when most dreaming occurs
As reported by Psych Central:4
“Sleep does not progress through all of these stages in sequence, however. Sleep begins in Stage One and progresses into stages 2, 3, and 4. Then, after Stage Four sleep, Stages Three, then Two are repeated before going into REM sleep. Once REM is over, we usually return to Stage Two sleep.
Sleep cycles through these stages approximately 4 or 5 times throughout the night. We typically enter REM approximately 90 minutes after falling asleep.
The first cycle of REM often lasts only a short amount of time, but each cycle becomes longer. This is why we need long periods of sleep each night as most of the REM sleep occurs in the hours before awakening.
If we get short periods of sleep, we can’t really get through the stages we need to heal and stay healthy. REM can last up to an hour as our sleep progresses. In case you are wondering, if you feel like a dream is taking a long period of time, it really is. Contrary to what was once believed, dreams take as long as they actually seem.”
Small Shifts in Your Sleep Cycle May Make or Break Your Health
If you’re wondering just how sensitive your sleep cycle actually is, you might be surprised to learn that it’s incredibly vulnerable to changes, such that even the small amount of sleep deprivation caused by Daylight Saving Time may be problematic.
One Washington University neuroscientist told CBS News that adjusting clocks forward one hour corresponds with a significant increase in traffic accidents and heart attacks5 over the next two to three days.
One study also found that the spring transition, which causes a phase advance, is particularly hard on the average person’s sleep-wake cycle,6 and while it’s generally thought that the loss of one hour of sleep on the night of the change is inconsequential, research suggests otherwise. According to a report in Sleep Medicine Reviews:7
“…data suggests that increased sleep fragmentation and sleep latency present a cumulative effect of sleep loss [following the spring transition], at least across the following week, perhaps longer.
The autumn transition is often popularized as a gain of 1 h[our] of sleep but there is little evidence of extra sleep on that night. The cumulative effect of five consecutive days of earlier rise times following the autumn change again suggests a net loss of sleep across the week. Indirect evidence of an increase in traffic accident rates, and change in health and regulatory behaviors which may be related to sleep disruption suggest that adjustment to daylight saving time is neither immediate nor without consequence.”
A One-Hour Difference Is a Huge Deal
As far as lack of sleep goes, research has shown that when participants cut their sleep from 7.5 to 6.5 hours a night, there were increases in the expression of genes associated with inflammation, immune excitability, diabetes, cancer risk, and stress.8 In other words, getting just one hour less sleep a night may raise your risk of multiple chronic diseases. Interrupted or impaired sleep can also:
Increase your risk of heart disease. Harm your brain by halting new cell production. Sleep deprivation can increase levels of corticosterone (a stress hormone), resulting in fewer new brain cells being created in your hippocampus. Impair your ability to lose excess pounds or maintain your ideal weight. This is likely the effect of altered metabolism, because when you're sleep deprived, leptin (the hormone that signals satiety) falls, while ghrelin (which signals hunger) rises. Contribute to a pre-diabetic state, making you feel hungry even if you've already eaten, which can wreak havoc on your weight. Accelerate tumor growth, primarily due to disrupted melatonin production. Melatonin inhibits the proliferation of a wide range of cancer cell types, as well as triggering cancer cell apoptosis (self-destruction). The hormone also interferes with the new blood supply tumors require for their rapid growth (angiogenesis). Contribute to premature aging by interfering with your growth hormone production, normally released by your pituitary gland during deep sleep (and during certain types of exercise, such as high intensity interval training). Raise your blood pressure. Increase your risk of dying from any cause.
A Simple Trick to Help You Stay in Deep Sleep Longer
Deep sleep is one of the most important sleep phases as your body repairs and regenerates, your immune system is strengthened and much more. The more time you can spend in this crucial sleep phase during the night, the more refreshed you’re going to feel in the morning, as well. Sound stimulation has been shown to be effective for prolonging deep sleep, so if you’re having trouble staying asleep at night, this is a simple trick to try.
Published in the journal Neuron,9 the study found that playing “pink noise” sounds that were synchronized to the subject’s brain waves when the subject approached deep sleep allowed them to remain in deep sleep longer than when the sound was not played. The participants were also shown 120 pairs of words before going to bed and tested the following morning to see how many they could remember.
After sound stimulation, the subjects improved their memory retention by nearly 60 percent, recalling an average of 22 sets of words compared to 13 when the sound was not played. The key, according to the authors, is that the frequency of the sound was synched to the subject’s brain waves. This produced an increase in the size of the brain waves during deep sleep, and these slower brain waves are associated with information processing and memory formation. You can find special “pink noise” apps to play in your bedroom, or you can simply turn on a fan to get this benefit.
Turn Off Your Gadgets and Avoid Other Common Sleep Disturbances
If your sleep is being interrupted, the first step is to determine the cause. If you’re a new parent being woken by a newborn, there’s obviously little you can do, aside from teaming up with your spouse or another family member so you can each have alternating nights of uninterrupted sleep. Most cases of sleep disruptions, however, will be related to environmental or emotional factors. Some common examples include:
- Eating a heavy meal, or spicy foods, too close to bed
- Pets in your bed or bedroom
- Pain (headache, menstrual cramps, back pain, etc.)
- Alcohol in the evening
- Use of your computer, tablet, cellphone, or television
That last one is a biggie, as about 95 percent of Americans use an electronic device within one hour of going to sleep, according to a National Sleep Foundation poll.10 This has a major implication on the quality of your sleep, in ways you might not even imagine. Certainly, such devices can keep you awake by making noises, but they also interfere with your sleep-wake cycle, or circadian rhythm, in far more insidious, and damaging ways.
Exposure to even small amounts of light from a television, your computer, tablet, or smartphone can interfere with your body’s production of melatonin, which helps regulate your sleep-wake cycle. Plus, when you're connected to the Internet, your phone or computer are communicating with nearby cell towers, which means they're also emitting low levels of radiation. One 2008 study revealed that people exposed to radiation from their mobile phones for three hours before bedtime had more trouble falling asleep and staying in a deep sleep.11, 12
According to the 2014 Sleep in America Poll, 53 percent of respondents who turn electronics off while sleeping tend to rate their sleep as excellent, compared to just 27 percent of those who leave their devices on.13 This is why I recommend avoiding watching TV or using a computer or tablet at least an hour or so before going to bed. If you do keep your devices in your room, make sure they are physically turned off along with your Wi-Fi router. An alternative, you can try a free computer program called f.lux (see justgetflux.com), which alters the color temperature of your computer screen as the day goes on, pulling out the blue wavelengths as it gets late.
How to Get Uninterrupted, Restorative Sleep
Small adjustments to your daily routine and sleeping area can go a long way to ensure uninterrupted, restful sleep. I suggest you read through my full set of 33 healthy sleep guidelines for all of the details, but to start, consider implementing the following changes. Number one on my list? As mentioned, turn off your electronic gadgets and keep them out of your bedroom:
- Avoid watching TV or using your computer/smartphone or tablet in the evening, at least an hour or so before going to bed.
- Make sure you get BRIGHT sun exposure regularly. Your pineal gland produces melatonin roughly in approximation to the contrast of bright sun exposure in the day and complete darkness at night. If you are in darkness all day long, it can't appreciate the difference and will not optimize your melatonin production.
- Get some sun in the morning. Your circadian system needs bright light to reset itself. Ten to 15 minutes of morning sunlight will send a strong message to your internal clock that day has arrived, making it less likely to be confused by weaker light signals during the night.
- Sleep in complete darkness, or as close to it as possible. Even the tiniest glow from your clock radio could be interfering with your sleep, so cover your clock radio up at night or get rid of it altogether. Move all electrical devices at least three feet away from your bed. You may want to cover your windows with drapes or blackout shades, or wear an eye mask when you sleep.
- Install a low-wattage yellow, orange, or red light bulb if you need a source of light for navigation at night. Light in these bandwidths does not shut down melatonin production in the way that white and blue bandwidth light does. Salt lamps are handy for this purpose.
- Keep the temperature in your bedroom no higher than 70 degrees F. Many people keep their homes too warm (particularly their upstairs bedrooms). Studies show that the optimal room temperature for sleep is between 60 to 68 degrees F.
- Take a hot bath 90 to 120 minutes before bedtime. This increases your core body temperature, and when you get out of the bath it abruptly drops, signaling your body that you are ready to sleep.
- Avoid using loud alarm clocks. Being jolted awake each morning can be very stressful. If you are regularly getting enough sleep, you might not even need an alarm.
- Be mindful of electromagnetic fields (EMFs) in your bedroom. EMFs can disrupt your pineal gland and its melatonin production, and may have other negative biological effects as well. A gauss meter and an electromagnetic smog detector are required if you want to measure EMF levels in various areas of your home. If possible install a kill switch to turn off all electricity to your bedroom. If you need a clock, use a battery-operated one.