One in three Americans has problems with going to sleep, staying asleep, or waking up in the morning. Here we discuss various sleep disorders and the role of melatonin and cortisol hormones.
Sleep is one of the most important daily tasks we do, without much thinking.
After a long day of work we feel sleepy, at some point in the night, then going to bed and fall asleep. It's a daily routine.
Our body temperature, cortisol and melatonin hormone levels also follow such a daily pattern that we call body clock or circadian rhythm.
We fall asleep in stages.
The first part of sleep is called non-REM, followed by REM sleep towards early morning before waking up.
REM sleep involves very rapid eye movement in all directions (that's why the name). It is deep sleep, with very low sense of outside world and relaxed muscles without much control of body temperature. However, it's only about 20-25% of the total sleep time, and occurs towards early morning.
Non-REM sleep has slow eye movement and some response to outside world (almost 80% of sleep is non-REM).
After we go to sleep our muscles relax, heart rate and blood pressure drop. These relaxed muscles in the wind pipe sometimes cause snoring and even blocking in some people leading to sleep apnea.
However, blood flow to brain increases during REM sleep in early morning; this need for high oxygen, more blood flow, and heart rate can cause blood clots, heart attacks and artery blockages, especially those with known heart problems; this is one reason why more heart attacks occur in early morning than any other time.
Sleep requirement are very different depending on the age.
Newborns need to sleep for almost 16 hours per day - about half of it is REM (until 3 months of age; then non-REM/REM pattern is set & REM duration slow decreases).
A 3-5 years old needs to sleep for almost 11 hours per day. By sixth year, REM sleep time stabilizes to about twenty five percent of the total sleep.
Adolescents (9-10 years old) also sleep for 10 hours a day. An average adult still requires 7.5 to 8 hours of sleep everyday.
However, in old age the hours of sleep change and we tend to have two sleep slots (night & day naps), similar to preschool children.
Over the counter melatonin for sleep is often used and is normally safe.
There are two competing forces to keep us awake and fall asleep. The urge to sleep gets stronger the longer we stay awake, a process called homeostatic drive.
Another force, called circadian rhythm or natural clock, tends to maintain a pattern and keep us awake in the morning and helps fall asleep in the night.
The control center of circadian rhythm is in our brain, just above where the sensors of the eyes connect to the brain. It's called SCN or supra (meaning above) chiasmic nuclei.
This circadian rhythm raises cortisol levels in the morning. But then they decreases slowly during the day.
At night, the sleep hormone, melatonin, is released to induce sleep.
These two systems that drive us to go to sleep are strongest at 2 am to 6 am and 2 pm to 6 pm. In fact, output of the SCN is highest in morning and lowest late at night/early morning.
The strongest urge to sleep is at 2-6 am; that's why the highest number of sleep related accidents happen during this time.
As the hourly trend above shows, cortisol is lowest during sleep. Melatonin levels rise and peak between 3 am to 5 am, then drop throughout the day. Then cortisol levels have a dramatic peak 30 minutes after waking up.
Growth hormone also released by the pituitary in pulses, which increase during the first one-third of the cycle, which is mainly non-REM sleep.
TSH levels peak in the evening but then drops during the sleep.
Testosterone levels in men continuously rise at night, from a nadir around 8 pm until a sharp peak in the morning at about 30 minutes after waking up.
Prolactin hormone levels peak 30 to 90 minutes after sleeping.
Body temperature falls during the sleep and is lowest in early morning. In fact, there is almost no temperature control during REM sleep.
Sexual arousal and tightening of sexual organs for both men and women is higher during REM sleep
Dreams are as natural as sleep. Majority of dreams (80%) happen in REM sleep (which is only about 20-25%) of total sleep.
Dreams from REM sleep are easy to recall, if you wake up right after this stage (e.g., if you wake up early, right after the REM sleep). Otherwise trying to recall dreams later tends to be difficult.
Interestingly, REM dreams are often unrealistic and bizarre. Colors appear bright, bold with intensity and clarity.
But non-REM dreams are often more realistic.
We use all five senses in our dreams: most often we see things, and hear them, but the use of touch, smell, and taste are less common (in that order).
Nightmares are very common in children aged 3-5 years but they tend to decline as hours of sleep change by age.
Anxiety and past stressful events (e.g., a car accident) can appear in dreams causing nightmares. But it's not yet clearly understood how the body causes nightmares and what is their role.
Melatonin is a hormone released by the pineal glands in our brain and regulates the sleep-wake up cycle and circadian rhythm .
Most animals have a circadian rhythm and their bodies release the sleep hormone, melatonin, in the night. Even nocturnal animals release melatonin in the night.
Therefore, light seems to have a clear role in blocking melatonin. Clearly, it is released only in darkness.
Melatonin levels start dropping 2 hours before we go to sleep and are highest around 5th hour of sleep.
Sleep hormone levels decrease with age, that's why chances of insomnia and sleep disorders increases with age.
Of the two stages of sleep, non-REM and REM (rapid eye movement), the non-REM phase changes much more than REM with age, especially during middle age.
Insomnia & sleep disorders increase the risk of mental health problems, depression and anxiety. They cause heart problems, high blood pressure, and host of other issues (e.g., acid reflux).
Sleep related breathing problems such as sleep apnea can increase the risk of diabetes, kidney and heart failure, AFib, and reduce our mental attention.
Suggested solutions include CPAP machines, surgery, weight loss and other breathing devices; however, they can cause problems such as poor sleep quality, dental damage, etc.
Over the counter sleep hormone, melatonin, for sleep is fairly common without any side effects. In general, melatonin is safe.
It has been shown to help many age groups: children with autism and ADHD, adolescents with depression, women during menopause, and patients with high blood pressure.
Light has a strong effect on melatonin levels.
Many studies show melatonin declines when exposed to strong light in the night.
Our eyes have evolved to adjust to low or high intensity light over time. In fact, studies of rats show that the structure of retina changes over time, to let a fixed number of photons into the eyes.
But we humans tend to require stronger light intensity to affect melatonin release, and can go back to sleep when light is switched off. Other mammals, e.g., rates need much lower light and can't go back to sleep once exposed.
In North America, typical outdoor exposure to light in summer is about 2.5 hours per day; and not more than 3 hours on weekends or outdoor days.
Any light that is much dimmer than what you are used to, might be sufficient to support melatonin release from pineal glands.
Melatonin release is associated with dim light, as we will see below.
But what's considered dim light?
A fluorescent lamp of 500 lux is the typical light at home and work.
Lux is a measure of light falling on a surface, and measured in lumens per square meter. (As light disperses, we get fewer lux for same lumens due to distance and spread.)
2500 lux from a 150 W flood incandescent lamp is same as indirect sunlight outside a window on a clear spring day.
In Antarctica, when sun doesn't shine, maximum light intensity is about 500 lux. Compare that to 100,000 lux we get on peak summer days.
On exposure to strong light (2500 lux), blood melatonin levels start dropping in about 10 mins & reach day time levels in about 1 hour. It takes about 40 mins for them to reach back to original levels.
(Secretion probably stops immediately but it takes time to observe the drop in blood or saliva as the half life of such drop is about 40-60 mins.)
For research studies and lab measurements, light below 10 to 30 lux is often used to start the release of melatonin and maintain the circadian rhythm.
In technical terms, it's called dim light melatonin onset (DLMO) or offset (DLMOff). DLMO is a good way to determine the transition phase of melatonin rhythm [when it rises above a certain minimal threshold, e.g., 10 pg/ml (43 pM)].
Saliva seems to be a better method to find the phase transition point or DLMO. One study found 16 out of 17 people had clear cut off in saliva samples.
It's best to not stand up while collecting saliva or blood samples. Sitting, reclining or lying flat don’t affect the results much.
One should minimize moving around & frequent posture changes as they might affect the results, especially within 10 mins of collection. This is mainly for caution, as another study showed no effect of posture on saliva or blood melatonin levels.
Even the extra light exposure in summer affects melatonin levels. A study to understand the role of constant light exposure on melatonin and circadian rhythm shows long exposure to relatively dim light prevents sufficient melatonin release & sleep. But short periods of strong light didn't have such an effect.
But there is good news.
Light can be used to reset the circadian rhythm pacemaker. One night of sleep deprivation and exposure to dim light can reset the clock.
In a study of 10 people, changes in dim light exposure helped shift the clock by up to 1.5 hours over a week.
Melatonin testing offers many options.
Saliva can be collected easily without invasive method or need of a healthcare professional. Also, good amount can be collected in short period, has fewer social taboos, and can be collected in many different settings.
Saliva measures the bioavailable fraction of melatonin, cortisol, and other hormones. This is the active part that's freely available in the tissues and not bound to anything else. It is especially accurate for topical hormone measurements (those rubbed to the skin).
However, melatonin measurement with saliva requires people to wake up, which can interfere with the regular trend.
Some studies show saliva has much better repeatability for the onset of melatonin release (DLMO), e.g., 16 out of 17 people showed repeatable results. The variations between people, and from night-to-night in same person were also low (in both cases 1.5-4.3 percent).
But saliva samples show the melatonin onset (DLMO) to be 40 minutes later than plasma.
Amount of melatonin in saliva is only about 30% compared to blood. Some variation is expected because one needs to wake up for saliva.
Urine measures the byproduct of melatonin, 6-sulphatoxymelatonin.
Urine samples have their unique challenges: the privacy of collection, the taboo with urine, the need for samples have to be spaced 2-4 hours apart for more precise assessment, the careful control of volume remaining in the bladder and the mixing from remaining volume in the bladder from last urination of the by product (6-sulphatoxymelatonin).
Saliva provides the melatonin at the given instant, while urine is an average of the time from last collection.
For any sample, day-time napping and vigorous exercise before collection should be minimized.
Our body clock has a well defined 24 hour clock. Many hormones rise and fall depending on the circadian rhythm, e.g., cortisol stress hormone and melatonin sleep hormone.
The circadian rhythm initiates sleep, normally about 2 hours before release of melatonin (dim light melatonin onset or DLMO).
This rhythm is unique to each one of us, and might be set earlier or later than normal sleeping times.
Problems with normal body clock or circadian rhythm are fairly common.
Whether your clock is set to later or earlier, the total sleep length should stay the same & one should wake up refreshed.
Sleeping and waking up late are common in younger age group. In fact, about 1 in 10 people with insomnia face this problem.
Sleeping and waking up earlier are common in older & middle-aged groups.
Shift in body clock is fairly common among night shift workers as about 20% of people work in such shifts.
A blood test of melatonin to understand circadian rhythm can be expensive and labor-intensive, often requiring special setting and healthcare professionals to monitor and collect the sample.
Saliva and urine based samples are simple, easy, inexpensive and can be collected at home to reflect the natural setting.
Treatments for fixing shifts in body clock often include bright and blue light to shift the clock earlier or later.
Cortisol is the hormone released by the adrenal glands on top of kidneys.
In the night, cortisol levels are the lowest. They start rising soon after waking up, with a sharp in 30-60 minutes.
This sharp rise in cortisol early in the morning is called Cortisol Awakening Response. It coincides with the early morning energy boost.
In a way, cortisol levels trend with our energy levels, high in the morning, then slowly fall and are lowest in the night.
The plot below shows this trend from a summary of 15 different studies of over 100k samples from almost 20,000 people.
In order to test for cortisol, four to six samples are collected throughout the day to see the diurnal cortisol trend.
For a healthy person, they should fall on this curve above.
Because morning cortisol levels rise and fall quickly, it is important to pick a time when the levels close to the peak.
The sketch below shows four points on this sharp rise within the first hour of waking up. Ideally, one should collect the sample at S1'' to capture the morning peak.
That means you should know the time you wake up. Not when you got out of the bed, but when you felt awake. An alarm is one way to clearly define this wake up.
Often, sleep disorders also cause confusion.
For late owls and morning larks, the melatonin and cortisol sample should be collected soon after waking up, without any confusion.
For those with irregular sleep, it's best to collect a sample after your last episode of morning sleep.
If you woke up late, it's okay to collect late. If you woke up too early and missed this time window, try next day. Waking up at 3 am or 4 am is common. Try collecting a sample if that's your regular wake up time.
It's best to reflect your daily routine to make sure the samples capture your current health conditions.
Please working in night shifts will see a shift in their daily trend. If they sleep during the day and wake up in the morning, their peak cortisol levels will be in the evening, right after waking up.
Therefore, melatonin and diurnal cortisol trends are dependent on the sleep pattern, not so much on day or night or sunlight.
Those with jet lag or other short term changes in sleep behavior should wait until they return back to normal routine.
Diurnal cortisol measurement is very useful for those with PTSD (post traumatic stress disorder), major depression, chronic fatigue syndrome, pituitary and adrenal gland problems, and those going through chemo treatments.
Those suspecting weight gain or work related stress should also consider checking their levels using an at home cortisol test kit.
The role of sleep remains a mystery.
But it's clearly necessary for so many reasons. Sleep is supposed to help restore and rebuild the body, especially for memory and cognition.
We still need to learn a lot. For example, it's not clear why REM sleep is not necessary for cognitive restoration. Similarly, role of non-REM sleep is not clear at all.
Sleep disorders are widespread, some may even say we have a epidemic of sleeplessness:
More than 40 million people have chronic sleep and wakefulness related problems.
One in three Americans has problems with falling asleep or staying asleep, or waking up in the morning or still feeling tired after waking up.
One in ten Americans says sleep problems interfere with their work.
One in 25 of them have sleep apnea (almost 10 million people).
One in five adults reports feeling sleepy during the day.
Work related stress, financial stress, PTSD, psychological stress, work related burn out, caregiver burn out, and physiological stress some common causes of sleep problems.
The risk of sleep disorders increases with age, and is higher in women and seniors.
They are more common in people with lower economic status & education, and those feeling chronic stress, anxiety, depression or drug and alcohol problems, and living with chronic medical conditions.
Broadly, sleep problems fall into two categories:
Night time: problem in falling asleep, staying asleep or in waking up.
Day time: sleepiness, tiredness, lack of attention and memorization, and unexpected mood changes.
Sleeplessness comes in many forms, but clinically there are four major categories of sleep problems:
Day time sleepiness - due to insufficient sleeping for lifestyle, work or behavioral reasons.
Insomnia - difficult falling asleep or waking up in-between, waking too early or too often, or feeling tired, irritable, depressed despite sleeping.
Unusual behavior during sleep, e.g., body movement, walking, teeth grinding (where a mouth guard for sleeping should be used).
Inability to sleep at the right time.
It's recommended to see a doctor if you face such problems at least 3 times a week for 3 months or longer.
Sleep problems can be due to many lifestyle or well known sleep disorders such as:
Sleep apnea, a serious condition in which people start snoring immediately after falling asleep.
Insomnia.
Health problems (e.g., diabetes, heart problems, etc.)
Mental health issues (stress, anxiety, social issues).
Medicine interference.
Neurological disorders (Alzheimer's, spine injury, epilepsy, etc.)
The short term effects of unhealth sleep include:
Lack of attention and concentration.
Accidents at workplace, on the road, and at home.
Absence from work and school.
Loss of productivity.
Effect on quality of life.
The long term effects of sleep deprivation include:
Obesity and unexpected gain in weight.
Diabetes.
Heart diseases.
High blood pressure.
Stroke, dementia, and cognitive decline.
Lower life expectancy due to accidents on road and workplace.
Mental health problems such as depression.
One in 25 men and 1 in 50 women have obstructive sleep apnea syndrome in the age group of 30 to 60 years old.
The numbers are even higher for men above 40 years and women in menopause. Three out of 4 patients are men, and 7 out of 10 are higher than normal weight.
Men are at twice the risk compared to women; age and obesity also increase the risk. During sleep apnea, people often feel they stop breathing in sleep and wake up.
Main cause of sleep apnea is relaxation muscles in mouth, throat and upper airway with age. These muscles relax and block the upper airway during sleep.
Continuous positive airway pressure or CPAP is one of the most common solutions of sleep apnea. The pressurized air helps open the airway and breath.
Proper mouth cover is important for avoid dry mouth. Sometimes a mouth tape for sleep is used to avoid air leakage from mouth.
Sleep apnea has a few clear symptoms:
Loud snoring immediately after falling asleep.
Feeling of choking during sleep.
Frequent waking up in the middle of sleep.
Sleep walking.
Unusual movements e.g., shaking hands or legs.
Heartburn and acid reflux.
Unusual night time sweeting.
Bed wetting (in children).
Uncontrolled sleeping during sitting and relaxing.
Forgetfulness and personality changes.
Dry mouth after waking up.
Blockage of upper airways and excessive weight.
There are serious health consequences of sleep apnea:
High blood pressure.
Heart attack.
Impotence in men over time.
Reduced quality of life.
Accidents are work and on the road.
Depression.
Insomnia.
It is the most common sleep related problem. Insomnia is difficulty in falling asleep or staying asleep or waking up too early in the morning.
Insomniacs feel tired during the day and do not feel refreshed after waking up. Sometimes it may be due to stressful situations, but root cause may not be easy to find.
It is serious health condition in which people fall asleep in the middle of an activity.
Narcolepsy often occurs due to muscle relaxation during a laughter, a joke, anger, surprise or a positive emotion. People tend to fall asleep very quickly (within 5 mins or so).
The sleep periods in narcolepsy are short, 15-40 mins and very relaxing. Usually their sleep is an REM sleep.
The DQB1*0602 haplotype have been associated with narcolepsy and can be checked to assess the genetic risk.
It is a well known condition that starts in young age but stays through out the life. It is a sensory-motor neurological disorder that runs in families but the causes are not fully understood.
Restless legs syndrome often occurs while lying in the bed or at the onset of sleep.
Women tend to be at higher risk. Studies of twins show there is a genetic component associated with restless legs syndrome.
Symptoms include a feeling of tingling, creeping, crawling, burning, cramping, aching, or knife-like itching sensations, mostly in lower legs between knees and ankles.
This causes a strong urge to move the legs. Serious conditions can make it difficult to fall or stay asleep.
It is advised to make sure you are hydrated to avoid any muscle spasms, which is unrelated to this problem.
Serum iron and ferritin levels should be checked for people with restless legs syndrome.
Education about sleep is very important before taking any treatment. Here are a few good sleep habits to follow:
Use consistent times for going to bed and waking up to maintain the circadian rhythm.
Limit time in the bed only to sleep.
Avoid the use of bed for activities unrelated to sleeping.
Minimize weekend night delays in sleeping or waking up late or longer sleeping hours to maintain a consistent pattern.
Find your preferred ways to fall asleep, e.g., sleeping on your back or side, face covered or with a dim room light.
No afternoon coffee or tea as caffeine is known to interfere with sleep.
Limit alcohol use.
Avoid daytime nap or limit to 30 mins and not late in the afternoon.
Try therapies before taking medication as therapies are often as effective & results are long lasting.
Therapies may include shorter sleep periods or relaxation techniques.
Exercise daily, 30-40 mins and at least 6 hours before sleep.
No strenuous exercise after 6 pm.
A hot bath for 30 minutes that raises body temperature by 2 degree centigrade, two hours before going to bed can help.
Avoid exposure to bright light before going to bed.
Minimize use of screens, especially those with blue light.
Try to get at least 30 minutes of sunlight during the day.
Keep the clock turned away.
Do not see the time if you wake up at night.
Try early dinner, no heavy eating or drinking at least 3 hours before bed time to prevent acid refluxes, heart burn or GERD.
Keep the bed room dark, quiet, ventilated, and at comfortable temperature throughout the night.
In multi-level houses, setup the bed room in lower level, if possible; heat rises up and rooms upstairs tend to be warmer.
Keeping the night temperature few degrees lower in the night might help in better sleep.
If you feel too warm or too cold, checking thyroid levels can help confirm the symptoms and plan for better sleep habits.
Bedtime rituals are known to help in falling asleep. Reading a book or other non-work related material can help.
Learn simple self-hypnosis for better sleep or going back to sleep. Relaxing, thinking of positive things, and ignoring distractions are all part of this process.
Try stress management tools and tricks and find the ones that work for you. Over time find ways that help you fall asleep fast.
Avoid unfamiliar environments for sleep.
Occasional over the counter melatonin for sleep is safe and might help; talk to your doctor if you need it for longer term.
Try sleep aids such as eye cover, comfortable pillows, stuffed animals, best side to sleep on, or soothing sleeping music if they can help you go to sleep.
A sound machine for sleep is possible option to avoid interference from outside noise.
Order an at-home Sleep and Stress Test kit.
Order an at-home Sleep and Stress Test kit.
All About Cortisol - a review of the stress hormone.
All About Thyroid - a review of the thyroid hormones.
All About Vitamin D – review of symptoms and impact.
Testosterone and Aging - how testosterone changes with age.
Hormones for Optimal Health – learn about some of the key hormones & their role.
Hormone Imbalance in Women - Role of Estrogen, Progesterone and Testosterone – learn about the three key hormones.
Hormone Testing - Role of FSH and LH Levels – summary of follicle stimulating hormone and luteinizing hormones.
Saliva Testing - Advantages and Challenges – review of science on saliva based testing.
Cortisol: Risk Factors – review of key risk factors for the stress hormones.
Morning Cortisol Levels – Why levels and collection times are so important.
