Sleep (or lack of sleep) in America today
A study by Connor Wild et al, (2018) ( 1 ) reports that a recent health survey in the US involving aroung 250,000 people, found that 29.2% of them were geting less than an average of 6 hours of sleep per night, which is a very low figure.
This value falls short of the recommended 7 or more hours of sleep per night. And it affects the day-to-day performance of these sleep deprived individuals. In fact, sleeping less than 6 hours per day is a medical condition known as chronic partial sleep deprivation (SD) or sleep restriction, which we know causes "impaired physiological and cognitive functioning".
The role of sleep
Sleep is an important vital function and essential for survival, otherwise, why would animals pay the cost of being vulnerable and immobile, unable to escape from predators, mate or eat?
This cost of sleeping suggests that it plays a crucial role in maintaining life and fitness. If it didn't, the pressure of evolution and natural selection would have favored animals that don't sleep.
Humans like all other animals must also sleep, but our modern society which is very different to the wild natural environment in which our species originated, acts upon us in ways that disrupt sleep patterns.
We humans also need to sleep (we spend almost one third of our lives asleep) and, until not so long ago, we were creatures that rose at dawn and went to bed at dusk, our days were occupied with foraging or hunting for food -plenty of physical activity- which was scarce -being overweight was uncommon- and stressors were tangible things like cave bears or lions.
Nowadays we stay up until late, illuminated with both strong and dim light at night (TVs, notebooks, smartphones), we are sedentary, overweight and chronically stressed out by intangible things that unfortunately never go away (work pressures, job-loss fears or financial woes). We travel and are subjected to jet lag or work during night shifts... all these factors disrupt our sleep patterns.
Conclusion: we aren't getting enough sleep. But, how much sleep do you need to maintain your health?
How much should you sleep?
The The American Academy of Sleep Medicine (AASM) and Sleep Research Society (SRS) weighed the evidence and defined the recommended amount of sleep needed by a healthy adult to maintain his or her health: More than 7 hours per night on a regular basis. ( 4 )
They point out that "Sleeping less than 7 hours per night on a regular basis is associated with adverse health outcomes, including weight gain and obesity, diabetes, hypertension,
heart disease and stroke, depression, and increased risk of death.
Sleeping less than 7 hours per night is also associated with impaired immune function, increased pain, impaired performance, increased errors, and greater risk of accidents.".
As you can see, the risks and conditions involved with poor sleeping habits are overwhelming.
For young adults and people who suffer from an illness the guidelines is to sleep more than 9 hours per night on a regular basis. However they warn that "...it is uncertain whether sleeping more than 9 hours per night is associated with health risk.".
Take home point
Get more than 7 hours sleep (9 if you are a young adult or recovering from illness).
Too little or too much sleep is very bad for you
A recent study by a team from the University of Western Ohio (Connor Wild et al, 2018) ( 1 ) found that the optimum amount of sleep to reach top brain performance is between 7 and 8 hours per night, and this value is independent of the age of the sleeper: it is valid for yound, middle aged and older adults.
The study involved over 40,000 people from around the world, who on average slept less than 6.3 hours per night -below the optimal value.
Sleeping more than 8 hours is, from your brain's point of view, as bad as sleeping less than 7 hours. Their key findings are:
- Sleep duration was associated with reasoning, verbal, and overall ability.
- But short term memory was unaffected by how long people slept.
- One single night's sleep can affect cognition.
A good or a bad night's sleep impacts on your brain
The study found that a single night of "poor sleep" -that is, moving away from the optimal value, impacted on cognition. On the other hand, moving towards the optimal value improved cognition.
This means that those who sleep too little (or too much) may see an improvement in their cognitive abilities in only one night of better sleep if it falls within the optimal values.
On the other hand, for a "normal" sleeper who regularly sleeps wthin the optimal 7-8 hour sleep range, sleeping less or more than that will negatively impact on their cognition.
Sleep and its impact on day-to-day life
Considering that almost 30% of Americans sleep less than 6 hours every night, we are surrounded by peple who function on low sleep levels and therefore suffer from problem-solving, communication, and reasoning abilities during their daily tasks. This affects the whole social fabric, from the CEO of a large corporation, to the humble blue-collar laborer.
Take home point
Sleep between 7 and 8 hours each night.
Don't sleep too too much either
In line with these guidelines, Alvarez and Ayas (2004) ( 3 ) report that those who sleep more than 8 hours a day or less than 7 hours per day "are at modestly increased risk of all-cause mortality, cardiovascular disease, and developing symptomatic diabetes".
Let's see what happens when you don't get enough sleep:
Lack of sleep damages your DNA and makes you put on weight
Researchers at Uppsala University in Sweden (Jonathan Cedernaes et al., 2018) ( 2 ) studied the tissue of sleep deprived people to try to find out why sleep provokes weight gain and loss of muscle mass. They found that: the DNA in certain tissue was modified by methylation, a process that regulates the switching on and off of genes.
Methylation is also known as an "epigenetic modification" and can be triggered by disease, age, lifestyle, environment (chemicals, pollutants) or even exercise.
Methylaton alters the way your DNA and can even cause cancer. In this case, lack of sleep caused epigenetic changes in "clock genes" within the body's tissues:
- DNA methylation in adipose or fatty tissue affected genes that are also altered by DNA methylation due to conditions such as obesity and type 2 diabetes
- "acute sleep loss may reprogram DNA methylation in adipose tissue to promote increased adiposity."
- "levels of structural proteins in skeletal muscle decrease in response to sleep loss"
Take home point
In conclusion, sleep loss promotes gain of fat mass and loss of muscle mass.
Only five nights of poor sleep can make your gain weight
Rachel Markwald (2013) (5 ) found that even five nights of insufficient sleep led to weight gain (almost 2 pounds in the subjects she studied). Although sleeping less provokes a higher energy expenditure (you burn more calories by being awake than when you sleep), the nightime after-dinner snacking by sleepless subjects caused them to eat more than they burned.
The effect of sleep loss on hunger is comparable to that of alcohol intoxication (drinking too much also makes you eat more).
Better sleep quality and quantity can help you lose weight
Thomson et al, (2012) ( 6 ) evaluated weight-loss success in relation to sleep quality and quantity: women who were dieting and slept better or slept more than 7 hours per night had 33% increase in weight-loss success when compared to those who didn't sleep well or as much (these had a 28% lower likelyhood of achieving their weight goals).
Take home point
Better sleep quality and quantity (+7 hours) will help you keep on track with your weight loss program.
Sleeping too little is bad for your heart
Men who sleep less than 5 hours per night double the risk for heart disease
A study involving 798 fifty-year old men in Gothenburg, Sweden was followed over a 21 year period to see if there was a link between sleeping too little and heart disease.
Its author, Moa Bengtsson (2018) ( 7 ) reported that "Men with the shortest sleep duration at the age of 50 were twice as likely to have had a cardiovascular event by age 71 than those who slept a normal amount".
This is cardiovascular risk, according to Bengtsson "is similar to that of smoking or having diabetes at age 50.".
Those who slept less than 5 hours per night were more prone to suffer from obesity, diabetes, high blood pressure, poor sleep quality and were also smokers and didn't exercise, when compared to those who slept 7 to 8 hours.
Napping and Sleep
Owens et al., (2010)( 8 ) studied the daytime napping habits and the nighttime sleep quality of a group of 224 Americans of different ethnic origins, middle-aged men and women.
Napping prevalence ranged from 10 to 65%. Those who were older or had poor health napped more and also had nighttime sleep problems.
They found that those who napped more:
- Slept for shorter periods at night
- Were more sleepy during daytime
- Suffered more fatigue
- Were fatter (higher body mass index, abdominal fat and waistline).
- Less efficient night sleep.
This created a vicious circle: poor nightime sleep led to a nap on the following day which in turn disrupted that day's nighttime sleep...
Take home point
Napping will affect your nighttime sleep quality and that will make you drowsy, fatigued and fatter.
Napping can affect health in older adults
Mantua and Spencer (2017) ( 9 ) look into napping and its apparently negative effects in older adults: they report that "frequent napping is associated with negative health outcomes in older adults". And suggest that this may be due to inflammation; the mechanism they propose is the following:
Lack of sleep provokes inflammation, so the body then tries to induce daytime sleep to fight it. With chronic inflammation (due to disease) napping may not be enough to normalilze it, but even so, the sick person will take a nap. This is the way that inflammation may be linked to frequent napping and poor health.
Sleep acts as a natural "Antioxidant"
A team from New York's University of Columbia (Hill et al., 2018) ( 10 ) asked what is the purpose of sleep, from a functional point of view. And to find out, studied a mutant strain of fruit fly that sleeps for a very short period of time. Drosophila flies are very useful laboratory subjects, they reproduce quickly and are cheap to handle and feed.
Surprisingly these short-sleeping flies had normal lifespans: at least in fruit flies chronic short sleep does not itself shorten lifespan.
They subjected the mutant flies and "normal" flies (which served as a control group) to oxidative stress by exposing them to chemicals and agrochemicals. The short-sleeping flies died off faster than the normal-sleeing ones. This shows that they cannot neutralize the high level of "free radicals" caused by this environmental exposure.
Free radicals (also known as reactive oxygen species or ROS) are highly reactive chemical compounds that unleash oxidative processes in the body by damaging molecules and causing "oxidative stress".
This molecular disruption damagesr DNA and the proteins and fats in the cells' nucleus and membranes. This disrupts the way cells work and harms the organism's health.
Free radicals are produced by external factors such as smoking, air pollutants, X-rays, UV radiation from sunlight and industrial chemicals and pesticides.
As their name indicates, they inhibit the action of free radicals, preventing oxidative reactions. They interrupt the chain reaction by "trapping" the ROS or reacting with substances that produce free radicals.
Some of the antioxidants are vitamins (A, E and C) and also flavonoids, polyphenols and some omega-3 fatty acids.
So they concluded that sleep plays an antioxidant role (less sleep means less antioxidants available).
Then they acted upon normal-sleeping flies to make them sleep longer and found that this increased their resistance to free radicals. Suggesting once again that sleep plays a crucial antioxidant role.
In a final test they fiddled with normal flies to reduce oxidative stress in their brains, and this reduced their sleeping time, which means that the presence or absence of free radicals regulates sleep. This is a two way relationship between sleep and oxidative stress:
- An increase in free radicals triggers sleep.
- Sleep acts as an antioxidant eliminating free radicals.
Alzheimer's, Parkinson and Huntington's diseases are linked with oxidative stress, maybe lack of sleep senstizes individuals to oxidative stress and makes them more prone to disease or, the opposite, the disease disrupts the antioxidant balance and causes loss of sleep.
Take home point
Sleep is an antioxidant that keeps you healthy
Tips to help you sleep
Having seen the damage that sleep causes let's see what we can do to sleep through the night with quality sleep. These are our tips:
How to sleep better at night naturally
"Food" for Good Sleep
Some food seems to have a sleep promoting effect:
Eat Prebiotics to Sleep better
Prebiotics are basicaly nondigestible food such as fiber and some short-chain fatty acids which promote the growth and activity of the "good" microbes in your colon and contribute to your overall health.
A paper by Robert S. Thompson et al., (2017) ( 11 ) found that a diet rich in prebiotics improve NREM sleep and enhance REM sleep because apparently it promotes the growth of Lactobacillus ramnosus bacteria. The exact mechanism is not known, but it also has stress-protective effects during daytime.
Food containing γ-aminobutyric acid or GABA
Yawen Zeng (2014) ( 12 ) reports that food rich in γ-aminobutyric acid (GABA) help improve sleep, however synthetic GABA should be avoided because it has side effects such as dizziness, drowsiness and even may cause addiction. Naturla GABA is virtualy harmless.
Microbes of the lactobacillus variety produce it by fermentation, so it can be found in certain fermented food such as kimchi, kefir, miso, sauerkraut, tempeh and yogurt.
Sleep-Promoting Foods and Sleep Quality
St-Onge, Mikic, and Pietrolungo, (2016) ( 13 ) reviewed scientific papers to identify the effect of different types of food on sleeping, and their findings are the following:
- Fatty fish is a good replacement for meat, not because it improves sleepiness but beause meat worsens sleep quality and should be replaced.
- Kiwi fruit. Eating 2 kiwis 1 hour before bedtime "enhances the sleep of individuals with self-reported sleep disorders and may also promote sleep in healthy individuals"
- Tart cherrie juice (drinkink 8 oz. in the morning) improve sleep quality and increase urinary melatonin concentrations (melatonin is a hormone that regulates wakefulness, more of it in the urine means more is available in the body).
- Malted milk "promotes less restless sleep in both young and old populations, although the mechanisms remain unclear".
- Natural melatonin-enriched milk, obtained by milking cows at nighttime (nighttime milk) "improved sleep efficiency and reduced the number of awakenings in middle-aged adults diagnosed with insomnia". In mice it has a sedative effect.
- Women should reduce carbs and fat intake. It has negative association with REM sleep.
- Diet quality close to bedtime influences sleep (eath healthy).
- Eating 30 to 60 minutes before bedtime has a negative impact on sleep quality (and it is worse in women than in men).
- Eating a sugary or starchy foods (food with a high glycemic index - or High GI food) 4 hours before bedtime may make you fall asleep faster but sleep quality is worse (more awakening, shorter deep sleep) especially if you eat simple sugars.
- "Higher saturated fat and lower fiber intakes may produce less [deep sleep periods], more nighttime arousals, and a reduction in overall sleep quality".
Take home point
Healthy foods will improve your sleep: yogurt, kefir, kimchi, fiber rich fruit and vegetables and food low in red-meat and unhealthy saturated fats and oils.
Avoid Dim Light at Night
Chul-Hyun Cho, et al. (2018) ( 14 ) studied the impact of "dim light at night" or dLAN (also known as blue light) on sleep in a group of women and found that exposure to dim light at night had a negative impact in the quality and total sleep time, sleep efficiency, increased wake time after sleep onset and an increase in REM sleep And, "based on previous studies, an increase in REM sleep due to dLAN exposure could be considered to have a somewhat negative impact on humans. Depression is known to be associated with altered REM sleep parameters".
Dim light is produced by our smartphones, ebooks, ipads, notebooks, PC screens, television, and street lights shining through windows.
Animal and human studies show that nightime exposure to dLAN negatively impacts metabolism, immune function and the sleep-wake cycle of the circadiam system.
Take home point
Leave your smartphone a couple of hours before going to bed. You will sleep longer and better.
A recent study (June 2018) published by Science Daily ( 19 )looked into the health risk effects of sleeping in an illuminated setting.
20 healthy adults were divided into two groups Dark-Dark and Dark-Light, the first group slept 2 nights in a dark room, while the other group (Dark-Light) slept the first nigh in a dark room and the second one in a room with an overhead 100 lux light.
The effect of one single night exposure to light while sleeping made the Dark-Light group's subjects insulin resistance higher which alters glucose transport out of the bloodstream and is a symptom that precedes the onset of type 2 diabetes.
Take home point
Sleep in the dark and you wil avoid the risk of diabetes.
The science behind a warm bath and sleeping better
Taking a warm bath or a shower is said to help you sleep better, but is it true? According to a study (Horne and Reid, 1985) ( 15 ) it is:
A cool 90-minute long bath didn't affect sleep parameters, but taking a warm bath there were " significant increases in: sleepiness at bed-time, slow wave sleep, and stage 4 sleep."
The baths were taken at 2:30 or 5:30 PM, so their impact on sleep is not necessarily immediate.
Take home point
A warm bath will help you sleep better.
Sleep and Exercise: the healthy link
There is an association between sleeping better and exercise, but it is a two way street: poor sleep can contribute to lower levels of physical activity.
Cristopher Kline reviewed the data ( 16 ), and concludes that:
Exercise improves sleep quality
- Exercise training reduces the severity of SDB or Sleep-disordered Breathing (obstructive sleep apnea or OSA is the most common type of SDB) by up to 32% even in people who were overweight.
- OSA severity decreased by 25% in people who engaged in 12 weeks of moderate-intensity aerobic training.
- Exercise training "also led to better subjective and objective sleep and improvements in daytime functioning (e.g., quality of life, depressive symptoms, vigor, fatigue)".
Poor Sleep impacts on Physical Activity
But adults suffering from insomnia are less active and "lower cardiorespiratory fitness than adults without insomnia, possibly due to daytime sleepiness and ⁄ or fatigue".
However sleeping more won't make you change your habits and exercise more: "improving sleep is insufficient to spontaneously change physical activity behavior", so if you sleep more you will feel better, but getting up and exercising more is up to you and your lifestyle choices.
Early birds and night owls
Kline points out that individuals' preferences (that is, being an early riser or a night owl) and the time that they go to sleep is closely linked to physical activity:
- Early risers or Larks (those who wake up earlier) tended to have greater levels of physical activity than "night time" people (slower to rise and prone to keep awake late into the night).
But what makes you an early bird or a night owl?
Morningness and eveningness are determined by many factors: some specific genes (circadian gene), age, sex, seasonal and geographic changes of light and dark, and also work or school schedules, shift work, jet lag and lifestyle. Cortisol levels in the morning (this hormone spikes shortly after you wake up) and the time in the evening that the body begins to produce melatonin to induce sleep.
In general you become a Lark as you age.
Take home point
Keep physically active, you wil sleep much better.
Some more Advice on Sleeping better and Faster
- A healthy diet, body weight and lifestyle will improve your sleep
- Keep a regular sleep schedule. Go to bed at the same time every day. This helps your body's sleep-wake cycle (or circadian rhythm keep in step).
- Sleep the same time each day, don't sleep in on weekends, you will be wide awake late at night.
- Avoid naps, they may help you recover energy, but may keep you up later in the day.
- Be in the sun during daylight hours it will regulate your melatonin production
- Relax and unwind 1 or hours before bedtime without TV, smart device screens or computers (avoid dim blue light).
- Relax in a warm bath
- Don't eat large meals before bedtime
- Caffeine is a no-no (don't drink tea, coffee or caffeinated cola beverages) after 4 PM
- Exercise, but do so at least 3 or more hours before bedtime.
- Alcohol disrupts sleep even though it may make you drowsy at first.
- Don't smoke before going to bed or in bed (it is also a fire risk).
- Sleep in a dark room if you don't fall asleep after 20 minutes, get out of bed. Return once you feel sleepy.
- Quiet and cool rooms also help improve sleep quality
- Keep hydrated but don't overdo it, you will be getting up during the night to get rid of the extra fluids.
- Stressed? Worried? there are Relaxation & Meditation techniques that can help you calm down and relax.
Sleeping well is a matter of following some simple healthy rules: exercise, eat a balanced diet, keep a bedtime routine that unwinds you both mentally and physically by reducing stimuli such as the TV or your smartphone screen.
Regular habits (going to bed at the same time each day and sleeping the same amount of hours) reinforce your circadian rhythm and will improve both quality and quantity of your sleep.
Cite this article:
A. Whittall. ©2018. Sleep Better. Patagonia Wellness, Nov. 09 2018. http://www.patagoniawellness.com/wellness/sleep.html
Subject: Sleeping better: tips on sleeping better naturally, simple habits and routines that can improve the quality and duration of your sleep and replenish your energy.
References and Further Reading
(1) Conor J Wild, Emily S Nichols, Michael E Battista, Bobby Stojanoski, Adrian M Owen. (2018). Dissociable effects of self-reported daily sleep duration on high-level cognitive abilities. Sleep, 2018; DOI: 10.1093/sleep/zsy182
(2) Jonathan Cedernaes et al., (2018). Acute sleep loss results in tissue-specific alterations in genome-wide DNA methylation state and metabolic fuel utilization in humans. Science Advances 22 Aug 2018: Vol. 4:8, eaar8590 DOI: 10.1126/sciadv.aar8590
(3) Alvarez GG, Ayas NT, (2004). The impact of daily sleep duration on health: a review of the literature. Prog Cardiovasc Nurs. 2004 Spring;19(2):56-9.
(4) Consensus Conference Panel, Nathaniel F. Watson, et al., (2015). Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep. 2015 Jun 1; 38(6): 843-844. 2015 Jun 1. doi: 10.5665/sleep.4716
(5) Rachel R. Markwald, et al., (2013). Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain. Proc Natl Acad Sci U S A. 2013 Apr 2; 110(14): 5695-5700. 2013 Mar 11. doi: [10.1073/pnas.1216951110]
(6) Thomson CA et al., (2012). Relationship between sleep quality and quantity and weight loss in women participating in a weight-loss intervention trial. Obesity (Silver Spring). 2012 Jul;20(7):1419-25. doi: 10.1038/oby.2012.62. Epub 2012 Mar 8
(7) European Society of Cardiology, (2018). Sleeping five hours or less a night associated with doubled risk of cardiovascular disease. 26 August 2018
(8) Owens JF et al., (2010). Napping, nighttime sleep, and cardiovascular risk factors in mid-life adults. J Clin Sleep Med 2010;6(4):330-335
(9) Janna Mantua and Rebecca M. C. Spencer, (2017). Exploring the nap paradox: are mid-day sleep bouts a friend or foe?. Sleep Med. 2017 Sep; 37: 88-97. 2017 Mar 6. doi: [10.1016/j.sleep.2017.01.019]
(10) Hill VM, O'Connor RM, Sissoko GB, Irobunda IS, Leong S, Canman JC, et al. (2018). A bidirectional relationship between sleep and oxidative stress in Drosophila. PLoS Biol 16(7): e2005206. https://doi.org/10.1371/journal.pbio.2005206
(11) Robert S. Thompson et al., (2017). Dietary Prebiotics and Bioactive Milk Fractions Improve NREM Sleep, Enhance REM Sleep Rebound and Attenuate the Stress-Induced Decrease in Diurnal Temperature and Gut Microbial Alpha Diversity. Front. Behav. Neurosci., 10 January 2017, https://doi.org/10.3389/fnbeh.2016.00240
(12) Yawen Zeng et al., (2014). Strategies of Functional Foods Promote Sleep in Human Being. Curr Signal Transduct Ther. 2014 Dec; 9(3): 148-155. 2014 Dec. doi: 10.2174/1574362410666150205165504
(13) Marie-Pierre St-Onge, Anja Mikic, and Cara E Pietrolungo, (2016). Effects of Diet on Sleep Quality. Adv Nutr. 2016 Sep; 7(5): 938-949. 2016 Sep 7. doi: [10.3945/an.116.012336]
(14) Chul-Hyun Cho, et al., (2018). Impact of Exposure to Dim Light at Night on Sleep in Female and Comparison with Male Subjects. Psychiatry Investig. 2018 May; 15(5): 520-530. 2018 Mar 19. doi: [10.30773/pi.2018.03.17]
(15) Horne JA, Reid AJ., (1985). Night-time sleep EEG changes following body heating in a warm bath. Electroencephalogr Clin Neurophysiol. 1985 Feb;60(2):154-7
(16) Christopher E. Kline, (2014). The bidirectional relationship between exercise and sleep: Implications for exercise adherence and sleep improvement. Am J Lifestyle Med. 2014 Nov-Dec; 8(6): 375-379, doi: [10.1177/1559827614544437]
(17) NIH National Institute on Aging, A Good Night's Sleep. Accessed Nov. 7, 2018
(18) National Sleep Foundation, Healthy Sleep Tips. Accessed Nov. 7, 2018
(19) American Academy of Sleep Medicine. Light exposure during sleep may increase insulin resistance: Chronic overnight light exposure could have long-term effects on metabolic function. ScienceDaily. ScienceDaily, 4 June 2018