How do you sleep?

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There is almost nobody who hasn't experienced sleeping problems at least once. These problems can be temporary or permanent, and often they are stress or job related. Usually we don’t know what constitutes a normal sleep, what the phases of sleep are, and how we can have a good sleep hygiene. We will try to answer these questions by bringing more information and advice in case sleep problems become serious.

According to statistics, almost 10% of Belgians have serious sleep problems and 60% of patients who visit a general practitioner are immediately being recommended a sleeping pill instead of getting a sleep analysis to identify the causes.

Most of us associate sleep with our body shutting down and relaxing, which is the opposite of what is actually happening. During sleep a number of vital tasks are being carried out so as to allow us to function at our best when we are awake. For example, a good sleep fights against infections, prevents anxiety and depression. To a certain extent, heredity determines how people sleep throughout their lives.

In 1910, we slept an average of 9 hours per night. Today, studies show that most adults sleep on average less than 7 hours.

Lack of sleep causes not only health problems such as stroke, heart disease, hypertension, diabetes, cognitive impairment but also billions of euros of economical loss. Weight gain was recently linked to little sleep; sleep is a powerful regulator of appetite and energy use. During a healthy sleep the body produces a hormone called leptin that acts as an appetite suppressor. The body also suppresses the production of a hormone called ghrelin, that acts as an appetite stimulant. The less people sleep, the more likely they are to be overweight or obese and to prefer eating foods that are high in calories and carbohydrates. Chronic sleep loss is also associated with an increased risk of premature death.  Women have a bad sleep more often than men, and this increase with age, very often after the age of 55.

The amount of sleep is less important than how deep the sleep is. Thinking about how many hours you SHOULD sleep often creates sleeping problems. Everybody wakes up a few times during the night, but good sleepers don't feel that. For those who can't fall sleep again it is better not to roll around in bed but to read. However, not on your mobile phone or tablet because of the blue light which can hinder your sleep quality.

The amount of sleep each individual needs varies from person to person and is age related:

Newborns: 16-18 hours/ day

Preschool children: 11-12 hours/day

School aged children and adolescents: at least 10 hours/night

Teenagers: 9-10 hours/night

Adults: 7-8 hours/night (10% of them, though, need less than 5 hours of sleep and 10 % need more than 7-8 hours)

Older adults: 7-8 hours/night

What happens during sleep?

The basic sleep physiology involves an endogenous sleep/wake cycle, sometimes referred to as circadian rhythm (“circadian” means “about a day”) and which is synchronized to the ambient light/dark cycle of the day. One of the most significant influences on the synchronization of the sleep/wake cycle is the environmental light received through our eyes.

Another key component to the circadian rhythm is a hormone called melatonin. The pineal gland releases melatonin to promote sleep during normal periods of darkness. This release is dependent upon environmental light and darkness: brighter light suppresses melatonin release and darkness increases it. Additionally, the type and wavelength of the light can influence the melatonin release. For example, red-wavelength light has the least effect on melatonin release, while blue-wavelength light has the greatest effect on melatonin suppression. A few examples of blue-wavelength light: fluorescent light bulbs, LED lights, television light, computer screens, smart phones and other mobile computing devices.

Working the night shift and being exposed to light at night has been linked to breast cancer, prostate cancer, diabetes, heart disease, and obesity.

Tips for decreasing exposure to blue light include:

-       Avoid looking at blue light screens (computer, TV, phone) 2 to 3 hours before bedtime.

-       Read with an incandescent light bulb rather than LED lights

-       If working a night shift, consider wearing blue-blocking glasses

-       Expose yourself to natural sunlight during the day

Stages of sleep

There are two basic types of sleep that have in total four distinct stages.

The first type of sleep is called non-rapid eye movement (REM) sleep or quiet sleep which consists of three stages:

Non-REM Stage 1 (N1): light sleep, easily awakened, muscles relaxed with occasional twitches, eye movements are slow (5 minutes).

Non-REM Stage 2 (N2): true sleep, eye movement stop, slower brain waves with occasional bursts of rapid brain waves (10-25 minutes).

Non-REM Stage 3 (N3): the restorative stage, it is needed for feeling well rested and energetic during the day, deep sleep, occurs soon after falling asleep, mostly during the first half of the night, difficult to awaken, large slow brain waves (Delta waves), heart and respiratory rates are slow, muscles are relaxed (up to 30 minutes, nearly absent in most people over age 65).

The second type (and fourth stage) of sleep or dreaming sleep is called REM sleep. It occurs about 90 minutes after falling asleep, with longer and deeper periods of this stage occurring during the second half of the night. The respiratory rate, heart rate and blood pressure are irregular, the eyes move rapidly, and dreams typically occur. REM sleep stimulates the brain regions that are used to learn and make memories. Other sleep stages may do this as well.

The four sleep stages repeat themselves continuously throughout the night varying in duration. As the nighttime hours progress, REM sleep time becomes longer, while time spent in N3 becomes shorter. Overall, almost one-half of the total sleep time is spent in N2 and about one-fifth in N3 and one-fifth in REM sleep.

The four most common sleep disorders:

-       Insomnia (nearly 50% are because of psychological or emotional problems)

-       Sleep apnea

-       Restless leg syndrome

-       Narcolepsy

Patients should seek help if they experience any of these symptoms more than three times per week and for at least one month:

-       It takes more than 30 minutes to fall asleep

-       Awaken several times a night with difficulty falling back to sleep

-       Awaken too early in the morning

-       Not feeling well rested in the morning despite getting 7-8 hours of sleep

-       Feeling sleepy during the day and falling asleep within 5 minutes of laying down for a nap, or falling asleep unexpectedly or at inappropriate times

-       Bed partner reports loud snoring, gasps, choking sounds or breathing stops for short periods

-       Creeping, tingling, or crawling feelings in legs that are relieved by leg movement or massage

-       Vivid dream-like experiences when falling asleep or dozing

-       Bed partner reports frequent arm and leg jerking during night

-       Regular use of stimulants to stay awake during the day

There are also many non-sleep disorder reasons that make sleeping difficult:

-       Caffeine- containing beverages (coffee, many teas, chocolate, and cola drinks) after 2 p.m., or noon if you’re caffeine-sensitive

-       Nicotine

-       Alcohol: it prevents deep sleep and REM sleep, allowing only lighter sleep stages

-       Medications: decongestants, steroids, some antidepressants, some blood pressure medications; to be checked with a pharmacist or family doctor

-       Depression

-       Psychological stress

-       Menstrual cycle

-       Menopause

-       Large meals: small amounts of food before bedtime may make it easier to fall asleep

-       Vigorous exercise before sleep (or at least not three-four hours before)

Recommendations to improve sleep:

-       Regular sleep schedule for bedtime and wake time even on weekends (the biological hour is very sensible at changes; there can be a so called social jet lag)

-       Physical activity: at least 20 minutes of moderate intensity two-three times per week (walking, cycling, swimming, gym)

-       Create a good sleep environment: room temperature around 18C, dark, quiet, avoid blue light from TV or smartphones, computer, reading light etc

-       Avoid caffeine, nicotine and alcohol (up to two hours before going to bed), large meals (low glycemic index food is, on contrary, recommended)

-       Avoid naps after 3 pm

-       Relax before bedtime: meditation, hot bath, warm non stimulant beverage

-       Talk with a health care provider if medications are the suspected cause of poor sleep

-       Natural sunlight: at least 30 minutes of daily natural outside sun exposure

-       Obtain a confortable sleep surface (the matress to be 160 m latime and 2 m latime for couples- French study Actilit); use the bed only for sleeping or sex

-       Don’t lie in bed awake: after 30 minutes of tossing and turning, get out of bed until sleepy

-       Certain teas or essential oils 

-       Luxtherapy- exposed to a lamp which has an influence on the biological hour (75% success) 

-       Behaviour therapy groups in the hospital.

-       Certain apps like Sleepbot, Deep sleep with Andrew Johnson, Sleep 101, Pzizz sleep, White noise lite

We tried white noise (you find it easy on Youtube) for a nap, and it gave us 30-35 minutes of good rest followed by a refreshing feeling. It is a noise similar to the one you usually hear on the plane.

In certain  cases, at the recommendation of the general practitioner, the patient is sent to a special clinic to do a polysomnography, a sleep registration. Sometimes a CT or MRI complete the examination.

One clinic is Adult Sleep Unit (Erasme Hospital, Brussels) which offers investigations in its sleep laboratory and address to anyone suffering from insomnia, vigilance disorders, hypersomnia, respiratory sleep disorders, snoring or any other sleep alteration. The sleep examination requires the recording of:

-       three EEGs (measuring brain activity)

-       one chin EMG (measuring muscular activity)

-       two electrooculogrammes (measuring eye movements)

-       one naso-oral airflow measure

-       measures of respiratory movements

-       snoring

-       one SaO2 (blood oxygen saturation measured by transcutaneous oximetry at the earlobe or finger)

-       lower limb movements

(thanks to prof. P. Linkowski for the sent information)


U.S. Department of Health and Human Services. Your Guide to Healthy Sleep. NIH Publication No. 06-5271. November 2005

Doghramji K, Markov D. Advances in the management of shift-work disorder, part I. Pathophysiology and health-related consequences. US Pharm. December 2011: 3-11.

Harvard medical School. Blue light has a dark side. Harvard Health letter. May 2012.

Harvard Health Publications, 2014

Thomas L. Lenz, Lifestyle Medicine for Chronic Diseases, Prevention Publishing, Inc, 2013