In this hectic world we live in with deadlines to meet, kids to take care of and housecleaning to do, many people consider sleep a luxury. According to the Centers for Disease Control and Prevention, one in three adults in the U.S.—about 37 percent—sleep less than seven hours per night.1 What’s more, over 20 years, the number of people who get less than six hours of sleep per night has increased.2
Who has time to turn out the lights early when your to do list is 10 miles long? Or maybe you have insomnia and can’t sleep. After all, you feel perfectly fine after getting only five or six hours of shuteye every night. Maybe that’s all you need.
But is this really true? Are six or less hours of sleep enough to keep you healthy or are you putting yourself at risk? Let’s take a look at what the research says about that as well as the idea that you can make up for lost sleep.
The Perfect Amount of Sleep
Many people think they’re getting enough sleep because they’re able to function and go about their daily routines. But, over time, if you’re not getting enough sleep, research shows you’re paying the price with your health and your life.
For starters, your overall quality of life is likely to take a nosedive if you’re not getting enough sleep. One study found that Korean men who slept four or less hours per night or 10 or more hours per night had significantly worse quality of life compared with men who slept seven hours. The researchers found similar results in the female subjects studied.3
Not only is your well-being at risk if you’re not getting enough sleep, your life may ultimately be at risk too. Rats deprived of sleep die within two to three weeks. In humans, many studies conducted over the last 40 years have painted a grim picture of getting either too little or too much sleep. In 636,095 men and 480,841 women taking part in the Cancer Prevention Study II from 1982 to 1988, participants who usually slept seven hours were the most likely to lead a long life. Subjects who slept six or less hours per night or more than eight hours had a higher mortality rate.2
Researchers who analyzed data from adults participating in the Alameda County Study found that people who slept six or less hours per night or nine or more hours had higher mortality rates than people who slept between seven and eight hours.4 Some researchers have found a greater risk of stroke in people who slept more than eight hours per night compared to people who slept between six and eight hours.5
Other researchers have found the association between getting too much or too little sleep and risk of death in older people as well. In one study, getting less than six or more than nine hours of sleep per night was linked to an increased risk of death in subjects older than 60.6
When you don’t get enough sleep, it puts you at risk for many diseases. This is the reason why less sleep may cut your life short—because it leaves you vulnerable to Alzheimer’s disease, diabetes, cancer, heart disease, high blood pressure and a weak immune system.
Lack of sleep might even be the reason why you’ve been packing on pounds, which in turn puts you at increased risk of heart disease and diabetes. So even though you think you’re coping just fine with five or six hours of sleep, your body might be telling you otherwise.
Your Drained Brain
Your brain and thinking processes undergo changes when you don’t get enough sleep. In fact, continually getting too little sleep is associated with a decreased attention span similar to the level seen in people who drive while drunk. Being awake for 19 hours from 8 a.m. to 3 a.m. is linked to a decrease in attention span and reaction time equivalent to a blood alcohol concentration of 0.05 percent. After 24 hours of being awake, the decrease in attention and reaction time equals an alcohol concentration of 0.10 percent.7
Sleep deprivation can shrink the region of your brain known as the hippocampus, resulting in a reduced ability to learn and poor memory.8 Not getting enough sleep also can stop the hippocampus from producing new neurons.9
Even scarier—ongoing lack of sleep increases the number of amyloid beta deposits, which are linked to Alzheimer’s disease, and increases the toxicity of amyloid beta.10 On the other hand, increasing sleep can lower the amount of amyloid beta deposited in the brain.10
Lack of sleep can make you less vigilant and wreak havoc on your attention span. After daylight savings time, adolescents experience a decline in vigilance.11 And male medical students, 18-25 years old, experience worse response times after 24 hours sleep loss.12
Your Heart Needs Sleep
Not all the research shows that short sleepers are at greater risk of heart disease. But there’s enough evidence to cause concern.
In 58,044 Chinese adults age 45 years old or older who did not have cardiovascular disease at the beginning of the study, sleeping five hours or less per night or nine or more hours per night was associated with death from coronary heart disease.13 Another study found a link between getting too little sleep (five or less hours) or too much sleep (11 or 12 hours) per night and developing carotid artery intima-media thickness (a marker of atherosclerosis).14
There’s also evidence to show coronary artery calcification—a risk factor for heart attacks—occurs at a much greater rate in people getting six or less hours of sleep compared to people getting seven to eight hours.15 Getting less than six hours of sleep per night also ups your risk of having high triglycerides and low high-density lipoprotein “good” cholesterol.16 And other studies found people who get the least sleep have a 60 percent or greater chance of developing high blood pressure.6
Less Sleep Equals More Weight Gain
If you’re wondering why you’re exercising and eating right, but you’re still gaining weight, take a look at your sleep habits. A lot of studies show that not getting enough sleep is connected to weight gain.
A group of researchers analyzed the medical literature to investigate the relationship between short sleep and weight gain. They looked at 17 trials that included 604,509 participants ages 15 to 102 years from Spain, Japan, the U.S., France, Switzerland, Sweden, Brazil, Finland, Norway, Canada, Hong Kong and the United Kingdom. The researchers found that sleeping less was significantly associated with obesity. They also analyzed studies that compared sleep loss in children and obesity. In both children and adults, there was a greater chance that the obese subjects slept fewer hours.17
Sleep loss does a number on hormones that control your appetite. It lowers your leptin levels, a hormone that controls satiety—your ability to become full after a meal—and boosts levels of the hormone ghrelin, which also can cause you to overeat.17
And That’s Not All
Shorter sleep duration is blamed for several other disorders. A number of studies have reported associations between getting less sleep and the risk of diabetes.6 Lack of sleep can also weaken your immune system. In a study of 153 adults, the subjects who slept less than seven hours per night were more likely to come down with a cold after exposure to the cold virus compared to subjects who slept eight hours or more.18 Getting less sleep also is associated with an increased risk of some forms of cancer, while night shift work is associated with an increased risk of breast cancer.6,19
What’s Behind It All
In some cases, the reason why people who sleep less than seven hours per night have an increased risk of death might have to do with sleep apnea, a condition where a person stops breathing intermittently throughout the night. It’s possible that the reason why many people are sleeping less than seven hours a night is because they’re suffering from sleep apnea, which is linked to high blood pressure and heart disease, among other diseases.20-23
Low melatonin levels are the main reason you’re paying the price for lack of sleep. The body produces the hormone melatonin in response to darkness. But if you’re burning the midnight oil and exposing yourself to light late at night, chances are good you’re deficient in melatonin. Low melatonin levels are linked to an increased risk of high blood pressure, heart disease, cancer, weight gain and metabolic syndrome, a cluster of risk factors for heart disease including abdominal weight gain, high blood sugar, blood pressure and triglycerides and low levels of the “good” cholesterol HDL.24-28
Can You Make Up for Lost Sleep?
The answer to this question involves good news and bad news. First, the good news.
In rats severely deprived of sleep, recovery sleep after being deprived of sleep reverses all the damage that was caused by lack of sleep, even after the animals were on the verge of death.29 Allowing sleep-deprived animals to once again get sufficient sleep also replenishes antioxidant supplies in the heart and the liver.29
More good news. In sleep-deprived humans, napping improves cognitive performance. In adults who were not sleep-deprived, napping during the day improved vigilance, memory and emotional processing.30
One group of researchers studied college students in a sleep research laboratory. Eighty college students were divided into two groups. One group took a 90-minute nap, the other group stayed awake. Before and after the test sessions, the students completed a vigilance test and a working memory task. The students who took the nap performed more accurately on the working memory task and experienced less lapses on the vigilance test. In the students who took the nap, working memory accuracy was linked to how long rapid eye movement sleep (REM) lasted, as well as total sleep time during the nap.30
In addition, daytime napping is linked to a lower risk of breast cancer among night-shift workers, who are at an increased risk of breast cancer due to their exposure to light at night.19
Now for the bad news. The benefits you reap from making up for lost sleep may be short lived. And the longer you go without sleep, the less making up for lost sleep helps restore your attention span.
A group of researchers investigated whether subjects sleeping 10 hours after being awake for more than 33 hours could make up for the lost shut-eye. The researchers put the subjects on this schedule for three weeks. In the first several hours after the subjects awakened, the 10 hours of recovery sleep did restore vigilance. However, later in the night, the subjects’ performance took a nosedive.
This was especially true when the subjects were already sleep-deprived for long periods of time, when the additive effect of ongoing sleep loss caused performance to decline rapidly late at night. In fact, the subjects’ performance on a test that measured attention and reaction time declined over time, so that reaction times were much less by the end of the study than at week one.7
“Data from this experiment reveal that individuals can develop a chronic sleep debt in the face of apparent full recovery from acute sleep loss,” the researchers wrote. “It is common for individuals to have relatively long sleep bouts on weekends or holidays but short sleep episodes on work or school days. Under such conditions, chronically sleep-restricted individuals may have a false sense of recovery from their previous sleep debt as a result of performing well for the first several hours of a usual waking day.”
The study found that when subjects were already fatigued because of ongoing sleep loss, the decline in attention and reaction time that occurred when they pulled an all-nighter was far worse than in people who pulled all-nighters, but who were not chronically sleep-deprived.7
According to the study authors, “This has important safety implications for the 16 percent of Americans who routinely sleep six hours per night or less, particularly those in safety-sensitive industries such as long-haul trucking.”
Solutions for a Good Night’s Sleep
Most importantly, if you snore, have insomnia or high blood pressure or heart disease, talk to your doctor about getting tested for sleep apnea. If the test turns out positive, sleeping with a device known as a continuous positive airway pressure (CPAP) machine can help you sleep better.
Since sleep loss causes free radical damage, sleep-deprived people can benefit from the antioxidant supplement N-acetylcysteine (NAC). Studies in mice have shown it can block the free radical damage and inflammation caused by sleep apnea. In humans with sleep apnea, NAC increased the amount of time spent in slow wave sleep, improved sleep quality, reduced the number of awakenings and sleep apnea episodes per night, improved the body’s ability to use oxygen and reduced the time spent snoring. None of these effects occurred in the subjects taking a placebo. The researchers concluded that long-term use of NAC in people who have sleep apnea may reduce their dependence on CPAP machines.31
Another solution for better sleep in people who have insomnia is emotional freedom technique (EFT). This technique involves tapping on your acupressure points while repeating certain statements. One study showed that EFT reduced insomnia in veterans.32
In addition, studies have shown EFT relieves tension headaches and reduces anxiety, depression and cortisol levels.33-34 To find an emotional freedom technique practitioner in your area, visit www.emofree.com.
Ideally, you never want to expose yourself to light after 11 p.m. to ensure your pineal gland secretes enough melatonin. Sleep in a dark room and don’t turn the lights on when you go to the bathroom in the middle of the night.
But avoiding light at night isn’t always realistic. To protect yourself against nighttime exposure to light, supplement with melatonin. This hormone also decreases the amount of time it takes to fall asleep, increases the amount of time spent sleeping and enhances overall sleep quality.35
Finally, inhaling lavender essential oil before bedtime can do wonders for your ability to get a good night’s rest. A number of studies have shown lavender essential oil can help people sleep better.36 In one of those studies, mothers who had recently given birth inhaled lavender essential oil before bed and placed a container with lavender-scented cotton balls next to their pillows. The result? After eight weeks of inhaling the lavender essential oil, the new mothers slept like a baby.37
Sleep Isn’t Optional
The majority of the research clearly shows that if you’re sleeping less, you could be shaving years off your life. If you’re skimping on sleep, you might be getting more done in the short term, but in the long term, you might not be around to reap the rewards of your efforts. Plus, your productivity will suffer.
By getting a solid seven to eight hours of sleep most of the time, you’ll live longer, be healthier and happier and very likely get more done in the time you are awake.
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- Kim JH, et al. J Clin Sleep Med. 2015 Feb 2. [Epub ahead of print.]
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- Grandner MA, et al. Sleep Med Rev. 2010 Jun;14(3):191-203.
- Cohen DA, et al. Sci Transl Med. 2010 Jan 13;2(14):14ra3.
- Kreutzmann JC, et al. Neuroscience. 2015 Apr 29. [Epub ahead of print.]
- Fernandes C, et al. Front Cell Neurosci. 2015 Apr 14;9:140.
- Tabuchi M, et al. Curr Biol. 2015 Mar 16;25(6):702-12.
- Medina D, et al. J Clin Sleep Med. 2015 Mar 23. [Epub ahead of print.]
- Dixit A and Mittal T. Indian J Psychol Med. 2015 Apr-Jun;37(2):165-8.
- Shankar A, et al. Am J Epidemiol. 2008 Dec 15;168(12):1367-73.
- Wolff B, et al. Atherosclerosis. 2008 Feb;196(2):727-32.
- King CR, et al. JAMA. 2008 Dec 24;300(24):2859-66.
- Kaneita Y, et al. Sleep. 2008 May;31(5):645-52.
- Cappuccio FP, et al. Sleep. 2008 May 1;31(5):619-26.
- Cohen S, et al. Arch Intern Med. 2009 Jan 12;169(1):62-7.
- Wang P, et al. Sleep Med. 2015 Apr;16(4):462-8.
- Aggarwal S, et al. Expert Rev Cardiovasc Ther. 2015 Jan 29:1-8. [Epub ahead of print.]
- Khayat R, et al. Eur Heart J. 2015 Jan 29. [Epub ahead of print.]
- Cho JS, et al. J Clin Hypertens (Greenwich). 2015 June 1. [Epub ahead of print.]
- Linz D, et al. Clin Res Cardiol. 2015 Apr 23. [Epub ahead of print.]
- Możdżan M, et al. Arch Med Sci. 2014 Aug 29;10(4):669-75.
- Lochner A, et al. Front Biosci (Elite Ed). 2013 Jan 1;5:305-15.
- McFadden E, et al. Am J Epidemiol. 2014 Aug 1;180(3):245-50.
- Cutando A, et al. Oncol Lett. 2014 Apr;7(4):923-926.
- Srinivasan V, et al. Recent Pat Endocr Metab Immune Drug Discov. 2013 Jan;7(1):11-25.
- Everson CA, et al. Am J Physiol Regul Integr Comp Physiol. 2005 Feb;288(2):R374-83.
- Lau EY, et al. PLoS One. 2015 May 13;10(5):e0125752.
- Sadasivam K, et al. Indian J Chest Dis Allied Sci. 2011 Jul-Sep;53(3):153-62.
- Babamahmoodi A, et al. Iran J Allergy Asthma Immunol. 2015 Feb;14(1):37-47.
- Bougea AM, et al. Explore (NY). 2013 Mar-Apr;9(2):91-9.
- Church D, et al. J Nerv Ment Dis. 2012 Oct;200(10):891-6.
- Ferracioli-Oda E, et al. PLoS One. 2013 May 17;8(5):e63773.
- Lillehei AS and Halcon LL. J Altrn Complement Med. 2014 June; 20(6):441-51.
- Keshavarz Afshar M, et al. Iran Red Crescent Med J. 2015 Apr 25;17(4):e25880.