Sleeping fewer than five hours a day more than doubles your risk of being diagnosed with angina, coronary heart disease, heart attack or stroke. And sleeping more than seven hours also increases your risk of cardiovascular disease; more than nine hours of sleep results in a 50 percent increase in risk.
The Daily Telegraph reports:
"The most at-risk group was adults under 60 years of age who slept five hours or fewer a night. They increased their risk of developing cardiovascular disease more than threefold ... Women who skimped on sleep ... were more than two-and-a-half times as likely to develop cardiovascular disease."
In related news, researchers have also found that sleeping in after a few days of missed sleep can help restore you after missed sleep, nearly erasing any lingering sense of fatigue and mental fuzziness.
How much recovery sleep you need to feel recharged depends on how much sleep you've lost.
In the study, volunteers deprived of about three hours of sleep a night for five nights felt nearly, but not quite, back to normal after ten hours of sleep.
To help you get the optimal amount of sleep each night, U.S. News & World Report suggests:
"... [T]ry removing all electronic media devices — BlackBerry, TV, computer — from your bedroom. These distractions … are a prime reason many of us turn out the lights an hour or two later than we originally intended."
According to this year's "Sleep in America Poll" by The National Sleep Foundation, the majority of Americans are not getting enough shut-eye. Only about four in 10 respondents reported getting a good night's sleep every night, or almost every night, of the week.
Despite it being so common as to be considered "normal" by many, lack of sound sleep extracts a heavy toll on your health, both mentally and physically.
How Lack of Sleep Impacts Your Health
Your circadian rhythm evolved over hundreds of generations to align your physiology with your environment. Your body clock is "set" to sleep at night and stay awake during daylight hours, just like your ancestors did.
If you deprive yourself of sleep, or switch your waking/sleeping rhythm due to shift work, for example, you send conflicting signals to your body.
Too little sleep impacts your levels of thyroid and stress hormones, which in turn can affect your memory, immune system, heart and metabolism, and much more. Over time, lack of sleep can lead to:
- High blood sugar levels and an increased risk of diabetes -- Sleep-deprived subjects tend to eat more sweet and starchy foods rather than vegetables and dairy products. Researchers suspect these cravings stem from the fact that your brain is fueled by glucose (blood sugar); therefore, when lack of sleep occurs, your brain searches for carbohydrates.
In short, sleep deprivation puts your body into a pre-diabetic state, and makes you feel hungry, even if you've already eaten.
- Weight gain -- When you are sleep deprived, your body decreases production of leptin, the hormone that tells your brain there is no need for more food. At the same time it increases levels of ghrelin, a hormone that triggers hunger.
- Accelerated aging
- Hypertension (high blood pressure) Depression
- Increased risk of cancer by altering the balance of hormones in your body. (Tumors grow two to three times faster in laboratory animals with severe sleep dysfunctions)
Likewise, working on a non-traditional schedule, which may include staying up all night, throws off your body's circadian rhythms. Attempts to sleep at inappropriate phases of the circadian cycle will usually result in shorter sleep episodes and more awakenings.
The short-term effects of shift work can be likened to symptoms of jet lag, such as daytime sleepiness, disturbed sleep, gastrointestinal problems and blunted alertness. Long-term, however, this state can take a toll, as shift workers continue live out of synch with their daily surroundings.
A number of studies indicate shift workers face a higher risk of heart disease -- possibly due to the metabolic effects of working and sleeping unusual hours.
In the latest study published in the journal Sleep, your risk of heart disease and stroke are also significantly increased if you sleep more, or fewer, than seven hours per day:
- Less than 5 hrs/night doubles your risk of angina, coronary heart disease, heart attack or stroke
- More than 7 hrs/night increases your risk of cardiovascular disease
- More than 9 hrs/night increases your risk of cardiovascular disease by 50 percent
Although the researchers were unable to determine the direct causative relationship between certain amounts of sleep and cardiovascular disease, they believe it is related to your endocrine and metabolic functions.
As mentioned earlier, sleep deprivation can impair your glucose tolerance, reduce your insulin sensitivity and raise your blood pressure, all of which are associated with hardening of your arteries.
Can You Really Repay a Sleep Debt?
The second Sleep study mentioned above found that by sleeping in, say on a Saturday, you can relieve some of the symptoms of sleep deprivation.
According to David Dinges, head of the sleep and chronobiology unit at the University of Pennsylvania School of Medicine,
"An additional hour or two of sleep in the morning after a period of chronic partial sleep loss has genuine benefits for continued recovery of behavioral alertness."
However, for most people who don't sleep well, it has become a lifestyle pattern, and sleeping in on the weekends is not going to undo the damage being done.
A chronic lack of high-quality sleep simply cannot be recovered. You may feel rested and mentally sharper after sleeping in, but the mental benefit is temporary, while the graver health hazards are compounding.
Remember, your body does most of its repairs during sleep, so not getting enough of it can impair your immune system, leaving you less able to fight off diseases of ALL kinds.
What's the Ideal Amount of Sleep?
There have been many varied theories on this over the years, but it seems we're getting closer to answering this question – at least scientifically.
Interestingly, while doing research on behalf of federal agencies "to find ways to reduce sleep need," Dr. Dinges discovered that many of the published reports on chronic sleep restriction over the past 100 years had failed to adequately control how much sleep was actually obtained by the subjects, and did not take into account caffeine intake and a number of other variables that can influence your sense of alertness and cognitive performance despite lack of sleep.
Many of these previous flawed studies have perpetuated the myth that you can safely make do with less than eight hours of sleep a day.
As it turns out, sleeping less than eight hours a night has significant cumulative consequences.
"Loss of sleep insidiously affects sustained attention, cognitive speed and accuracy, working memory, reaction time, and overall behavioral capability, often without the sleep-deprived person being aware of the deficits.
… These experiments have consistently demonstrated that neurobehavioral deficits develop in proportion to the dosage of sleep that people were allowed each night. When sleep was less than eight hours night after night, subjects showed systematic accumulation of cognitive impairments.
Across 10 days of restricted sleep, participants became progressively worse and eventually entered a zone of impairment comparable to that found after total sleep deprivation. This is a zone of impairment where it would be unsafe to drive or engage in other safety-sensitive tasks."
Likewise, chronic disease states such as heart disease and diabetes take time to develop, and are therefore also influenced, long-term, by your sleeping habits over time.
That said, what IS the ideal amount of sleep?
Well, despite what you just read above, there's no one magic number that covers everyone at every age and circumstance.
Your age and activity level will determine your sleep needs to some extent. Children and teens, for instance, need more sleep than adults. However, your sleep needs are individual to you. You may require more or less sleep than someone of the same age, gender and activity level.
Part of the reason for the difference has to do with what the National Sleep Foundation (NSF) calls your basal sleep need and your sleep debt:
- Basal Sleep Need: The amount of sleep you need on a regular basis for optimal performance
- Sleep Debt: The accumulated sleep lost due to poor sleep habits, sickness, environmental factors and other causes
Studies suggest that healthy adults have a basal sleep need of seven to eight hours each night, corresponding nicely with the research findings just discussed.
But your individual sleep requirement may be anywhere between six and nine hours of sleep a night.
Your best bet is to listen to your body!
If you still feel tired when the alarm goes off, you probably aren't getting sufficient sleep.
It's best to observe how you feel immediately upon awakening rather than after you're up and moving around. Those first few moments of wakefulness, before your mind fully kicks into gear, are a better measure of how your body is feeling.
How to Improve Your Sleep
First of all, if you're staying up late watching TV, surfing the Web, or working, it's time to set some limits. Determine a set bedtime for yourself, just as you do for your children, and avoid watching TV or using electronics for about an hour prior to going to bed. It is too stimulating to your brain, making it more difficult to "shut down" and fall asleep.
Instead, try spending this wind-down time doing something that soothes and relaxes your mind. You may want to spend time journaling, meditating, sipping herbal tea, washing your face, or reading a calming or spiritual book.
I also recommend getting to bed as early as possible. Your bodily systems, particularly your adrenals, do a majority of their recharging or recovering during the hours of 11 p.m. and 1 a.m., so you should definitely try to be asleep during those hours.
If you're having trouble falling or staying asleep because your mind is still racing or you're emotionally overwhelmed, I recommend you use Emotional Freedom Techniques (EFT) for insomnia.
Other tips for getting good quality sleep include:
- Avoid before-bed snacks, particularly grains and sugars. This will raise blood sugar and inhibit sleep. Later, when blood sugar drops too low (hypoglycemia), you might wake up and not be able to fall back asleep.
- Eat a high-protein snack several hours before bed. This can provide the L-tryptophan need to produce melatonin and serotonin.
- Keep the temperature in your bedroom below 70 degrees F. Many people keep their homes and particularly the upstairs bedrooms too hot.
For a comprehensive list of practical solutions for sleep problems, be sure to read my 33 Secrets to a Good Night's Sleep.
If you're even slightly sleep deprived I encourage you to implement some of these tips tonight, as high-quality sleep is one of the most important factors in your health and quality of life.