By Dr. Mercola
If you’re trying to lose weight or maintain your current weight, you probably know the drill. Eat right, exercise and get a handle on your stress levels. But there’s another factor that many people overlook; it’s insidious and can sabotage even the most determined among us: sleep.
Or, more specifically, lack of sleep. This presents a hurdle to weight loss and maintenance in a number of ways, including affecting your food cravings. Trying to eat right when you’re sleep deprived is like trying to dry off in the rain; it’s very difficult.
When you’re tired, your body is running on reserves and what energy you do have you’ll devote to the essential tasks of your day – caring for your children, work obligations and the like.
While on a day you’re feeling well-rested you might also have the energy to devote to planning and preparing healthy meals, on a sleep-deprived day you’ll probably succumb to the temptation to just order takeout. There’s far more to this cycle than simple lack of energy, however.
Lack of Sleep Gives You the Munchies
“The munchies” is a well-known phenomenon associated with marijuana use. The drug makes junk foods seem irresistible, and when you eat them they taste especially flavorful and satisfying. But it’s not only marijuana that causes the munchies – so, too, does sleep deprivation.
Like marijuana, it’s believed that “sleep restriction is associated with activation of the endocannabinoid (eCB) system, a key component of hedonic pathways involved in modulating appetite and food intake,” according to recent research published in the journal Sleep.1
The study compared the effects of four nights of normal sleep (8.5 hours) with four nights of restricted sleep (4.5 hours) among 14 young adults. Levels of endocannabinoid 2-arachidonoylglycerol (2-AG), a chemical that makes foods pleasurable, were elevated when the participants were sleep deprived.2
Sleep Deprivation May Elevate 'Hunger Chemical' 2-AG
On a typical day, your 2-AG levels tend to be low overnight then rise slowly until they peak in the afternoon. But in those who were sleep deprived the levels stayed elevated until late in the evening. According to the researchers:3
“When sleep deprived, participants reported increases in hunger and appetite concomitant with the afternoon elevation of 2-AG concentrations, and were less able to inhibit intake of palatable snacks.”
When the participants had less sleep, they ate snacks with more carbohydrates along with close to double the amount of fat and protein compared to when they were well rested.
While past research has shown lack of sleep influences hormone levels, including increasing the “hunger hormone” ghrelin and decreasing leptin, which is involved in satiety, this is the first study to show it may also influence the endocannabionoid system.
Frank Scheer of the Medical Chronobiology Program at Brigham and Women's Hospital in Boston said in a related commentary:4,5
“The increase in the peak in endocannabinoids following sleep restriction provides an additional mechanism that could help explain an increase in hunger.”
Is Light Pollution Interfering With Your Sleep?
Nearly half of Americans report sleep-related problems,6 and one reason for sleepless nights may be light pollution.
People who live in neighborhoods with ample amounts of nighttime light, including neon signs and streetlights, are more likely to report sleep problems, according to researchers at the Stanford Sleep Epidemiology Research Center in California.7
Those affected by high nighttime light exposure were 13 percent more likely to be dissatisfied with their sleep quality or quantity. They also slept less (by about 10 minutes a night) and reported more fatigue, excessive sleepiness and impaired functioning.
As expected, nighttime light exposure was more intense – by up to six-fold – in densely populated urban areas than in rural areas or small towns. Streetlights are to blame for the majority of light pollution worldwide, according to the International Dark-Sky Association.8
Artificial light, whether it be from streetlights or your computer screen, may interfere with the functioning of the suprachiasmatic nucleus of your brain (SCN), which is part of your hypothalamus.
Based on signals of light and darkness, your SCN tells your pineal gland when it's time to secrete melatonin — a powerful antioxidant and free radical scavenger that helps combat inflammation.
Artificial lighting disrupts your biological clock and melatonin production, which in turn impairs your immune function. Melatonin also helps protect your brain health and is a very potent anti-cancer agent.
Cells throughout your body — even cancer cells — have melatonin receptors. So when melatonin makes its nightly rounds (its production peaks during the night), cell division slows. But if your sleep environment is too bright, you’ll miss out on this cancer-fighting benefit.
Noise Pollution May Also Interfere With Your Sleep
In the U.S. it’s estimated that 100 million people are exposed to unhealthy levels of noise pollution, typically from automobile and aircraft traffic (although everything from leaf blowers and lawnmowers to loud music can also contribute).9
Noise pollution may increase your risk of hearing loss, but it goes much further than that. Stress, sleep disturbances, diminished productivity and even heart disease can also result.
One of the key ways excessive noise harms your heart is by elevating stress hormones such as cortisol, adrenaline, and noradrenaline, which, over time, can lead to high blood pressure, stroke and heart failure.
One review of research showed that "arousal associated with nighttime noise exposure increased blood and saliva concentrations of these hormones even during sleep."10 Particularly concerning, at least as far as sleep troubles go, is construction work and other noise pollution that occurs at night.
Erica Walker, a Ph.D. candidate at Harvard’s T.H. Chan School of Public Health, is conducting a study on noise levels in Massachusetts and how they affect residents’ health (including their mental health).
She may soon expand to New York’s Brooklyn Heights, where residents are facing nighttime construction noise that interferes with sleep. As reported by The Atlantic:11
“ … lifelong New Yorkers Roberto Gautier and his wife, Elissa Descoteau, live in a 23rd-floor affordable condo on Cadman Plaza near the Brooklyn Bridge. There, the city has been rehabilitating the historic bridge for the past five years.
So as not to disrupt daytime traffic across the historic span, construction clatter—the shrill beeps of construction vehicles backing up, the ting of steel striking steel, and even jackhammers—often begins at 11 p.m. and continues through the night.”
Too Little Sleep Fuels Weight Gain Even in Children
The biological mechanisms linking sleep deprivation and weight gain are numerous, but include metabolic changes, altered insulin sensitivity, and biological stress mechanisms that affect genetic expression. This is true not only in adults but also in children.
With rates of obesity among children skyrocketing, addressing sleep issues is incredibly important. Even relatively small changes in sleep habits, such as increasing or decreasing sleep by 1.5 hours a night, have an impact.
For instance, in one study children aged 8 to 11 either increased or decreased their time in bed by 1.5 hours a night for one week, then reversed the schedule for another week.
When the children slept more, there were significant benefits reported, including consuming an average of 134 fewer calories per day and weighing half a pound less.12 In 2011, researchers similarly found that each additional hour of sleep per night at ages 3 to 5 was associated with a 61 percent reduction in the risk of being overweight or obese at age 7.13 And, significantly, the increases in weight were due to increases in fat mass, specifically.
In 2013, separate research also showed that getting just one extra hour of sleep a night was linked to a 28 percent lower risk of being overweight and a 30 percent lower risk of being obese.14
A Restful Night’s Sleep Is Essential for Good Health
The many disruptions provoked by lack of sleep cascade outward throughout your entire body, which is why poor sleep tends to worsen just about any health problem. For example, in addition to fueling your junk-food cravings, interrupted or impaired sleep can:
Contribute to a pre-diabetic state, making you feel hungry even if you've already eaten, which can wreak havoc on your weight 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 Aggravate or make you more susceptible to stomach ulcers Raise your blood pressure and increase your risk of heart disease Promote or further exacerbate chronic diseases such as: Parkinson’s, Alzheimer’s, multiple sclerosis (MS), gastrointestinal tract disorders, kidney disease, and cancer 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) Worsen constipation Increase your risk of dying from any cause Worsen behavioral difficulties in children Increase your risk of depression. In one trial, 87 percent of depressed patients who resolved their insomnia had major improvements to their depression, with symptoms disappearing after eight weeks Alter gene expression. Research has shown that when people cut 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 stress15 Aggravate chronic pain. In one study, poor or insufficient sleep was found to be the strongest predictor for pain in adults over 5016
How Is Your Sleep Hygiene?
You probably have a hygiene routine you use to get ready every morning, but how is your “sleep hygiene”? Proper sleep hygiene is important to achieve more restful, restorative sleep. I suggest you read through my full set of 33 healthy sleep guidelines for all of the details. To start, consider implementing the following changes:
- Avoid watching TV or using your computer in the evening, at least an hour or so before going to bed. These devices emit blue light, which tricks your brain into thinking it's still daytime. Normally, your brain starts secreting melatonin between 9 pm and 10 pm, and these devices emit light that may stifle that process. Even the American Medical Association now states:17
“…nighttime electric light can disrupt circadian rhythms in humans and documents the rapidly advancing understanding from basic science of how disruption of circadian rhythmicity affects aspects of physiology with direct links to human health, such as cell cycle regulation, DNA damage response, and metabolism.”
- 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.
- Sleep in complete darkness, or as close to it as possible. The slightest bit of light in your bedroom can disrupt your body’s clock and your pineal gland's melatonin production. Even the tiniest glow from your clock radio could be interfering with your sleep, so cover your 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. If this isn’t possible, wear an eye mask.
- 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. You can also download a free application called F.lux that automatically dims your monitor or screens.18
- 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.
- Get some sun in the morning, if possible. 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. More sunlight exposure is required as you age.
- Maintain a regular sleep schedule. You should go to bed and wake up at the same times each day, even on the weekends. This will help your body to get into a sleep rhythm and make it easier to fall asleep and get up in the morning.
- Establish a bedtime routine. This could include meditation, deep breathing, using aromatherapy or essential oils or indulging in a massage from your partner. The key is to find something that makes you feel relaxed, then repeat it each night to help you release the tensions of the day.
- If you can’t sleep, don’t stay in bed. Lying in bed trying to sleep is frustrating and can create anxiety. If you can’t fall asleep, leave your bed and listen to some soft music or read a book until you feel sleepy, then go back to bed and try again.
- 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 is required if you want to measure EMF levels in various areas of your home. Ideally, you should turn off any wireless router while you are sleeping. You don’t need the Internet on when you are asleep.