It’s normal to have trouble sleeping every now and again—especially considering just how many factors play a role (stress, hormones, aging, diet...the list goes on). But how do you know if occasional nights spent tossing and turning are symptoms of a sleep disorder? When does “poor sleep” cross the line into insomnia? What about sleep apnea?

While the list below is by no means exhaustive, it’s a starting point to help understand the potential causes of fatigue (i.e. low energy) and Excessive Daytime Sleepiness, or EDS (i.e. fighting to stay awake)—all of which are signs that it’s time to consult a sleep specialist.

1. You’ve had trouble falling + staying asleep at least 3 nights/week over the course of 1 month (despite adequate opportunity for it)

Although the term “insomnia” is thrown around quite a bit, by scientific standards, it’s specifically defined as “inadequate quantity or quality of sleep characterized by a subjective report of difficulty with sleep initiation, duration, consolidation, or quality that occurs despite adequate opportunity for sleep, and that results in some form of daytime impairment and has persisted for at least one month.” (1)

To put it simply, if you’ve experienced trouble falling or staying asleep at least three nights a week for at least a month, despite doing everything right (cold, dark room with minimal pre-bed screen time and no interruptions throughout the night), you may be suffering from chronic insomnia, which typically (but not always) causes fatigue rather than EDS. 

How chronic insomnia is diagnosed:

If you haven’t already done so prior to your appointment, your doctor/sleep specialist will likely ask you to keep a journal for at least two weeks in order to track sleep and wake times, eating times, exercise times, and general mood. This way, s/he will be better equipped to identify any recurring patterns, properly diagnose chronic insomnia, and suggest a tailored course of treatment to help you get better sleep on a regular basis.

Tools your doctor may consider using in diagnosing insomnia include:

  • Actigraphy: A small motion sensor that you wear for up to two weeks in order to measure sleep quality
  • Blood tests: To screen for thyroid hormone imbalances or other medical conditions that might cause insomnia
  • Mental/physical health questionnaires: Insomnia can occur by itself as an independent problem or in conjunction with mental and physical health problems, which is why questionnaires about alcohol use, smoking, caffeine use, etc. are common.

If it’s determined that insomnia is the culprit, your doctor will also work with you on making sustainable behavioral change, including (but not limited to):

  • Avoiding clock watching
  • Developing a nighttime routine
  • Limiting blue light exposure
  • Practicing proper in-bed behavior (don’t spend too much time awake in bed)
  • Getting on a consistent sleep schedule
  • Progressive muscle relaxation techniques

S/he may also refer you to a behavioral sleep medicine specialist trained in cognitive behavioral therapy for insomnia (CBT-I). CBT-I is recommended over traditional sleep pills (sedative-hypnotics) because it is as effective, (2) not to mention safer with longer-lasting benefits.

2. Your sleep is disrupted due to (your own) snoring

If this is the case, you may be suffering from EDS due to apnea, a sleep disorder marked by temporary pauses in breathing throughout the night. Unlike the less common Central Sleep Apnea, which occurs when the brain fails to send correct signals to the muscles in charge of breathing, Obstructive Sleep Apnea (OSA) occurs when throat muscles relax (or your airway is reduced), partially or completely blocking the airway and leading to snoring (that’s often loud enough to be heard from the hallway outside your bedroom with the door closed) or gasping for breath. A major risk factor for OSA is obesity; however, it’s also particularly common among menopausal women—studies indicate that about 20% develop some form of the condition. (3)

Apnea exists on a spectrum, meaning it doesn’t manifest the same way for everyone. Some experience mild, general snoring due to upper airway resistance that doesn’t affect blood oxygen levels while others have more severe cases in which blood oxygen levels drop. Known as hypoxemia, this stresses out the entire body and can contribute to hypertension, stroke risk, cardiovascular disease, etc.

What makes OSA so tricky is that many people don’t know they have it—for some, the only symptom is unexplained sleepiness or needing to sleep more than usual to feel rested, while others may experience sleep disruptions due to snoring or a feeling of gasping for air.

How OSA is diagnosed:

Your healthcare provider or sleep medicine specialist will recommend you enroll in an overnight sleep study known as a polysomnography (or PSG), in which several EEG sensors are placed on the head to identify brainwaves and differentiate when you’re awake or asleep (and in what stage). There are other sensors that also track breathing, snoring, limb movement, and heart rate across the night in order to screen for and diagnose other conditions such as narcolepsy (more on that below). (4) 

It's also possible to conduct a home study outside of a sleep center. This involves fewer sensors and does not require an EEG to measure brainwave activity.

3. External factors prevent you from getting adequate sleep

Unlike insomnia, which occurs despite the opportunity to sleep, Insufficient Sleep Disorder is caused by social or work-related factors that prevent you from obtaining an adequate amount of sleep each night.

As a rule of thumb, adults 25 years and older should get seven or more hours of sleep/night. (5) Anything below that is highly unusual and a potential sign of Insufficient Sleep Disorder.

How Insufficient Sleep Disorder is diagnosed:

A sleep specialist will recommend a sleep study to rule out other disorders that may be causing your EDS symptoms.

If you’ve ruled out the first three causes listed above, then it’s time to move onto the less-common, but equally-as-disruptive sleep disorders that merit a visit to a specialist.

4. You find yourself unwillingly falling asleep in the middle of a daytime activity

If you have sudden attacks of sleep during the day, so much so that you find yourself falling asleep while doing routine tasks or in response to an emotionally charged situation, you may have narcolepsy. This chronic neurological condition impacts the brain’s ability to regulate the sleep-wake cycle (also known as the circadian rhythm) and, as a result, causes interrupted sleep throughout the night. Other symptoms include sudden muscle weakness (cataplexy), vivid hallucinatory dreams, and paralysis just before or after sleep.

How narcolepsy is diagnosed:

Because narcolepsy has several potential causes (e.g., family history, past brain injury, autoimmune disorders), sleep doctors typically conduct a full clinical examination and medical history assessment, which also help rule out or identify other contributing neurological conditions. Doctors may also recommend a two-week sleep journal in order to confirm cataplexy, which is unique to narcolepsy.

Available diagnostic tests include:

  • Polysomnography (PSG) 
  • Multiple sleep latency test (MSLT): A test of daytime sleepiness that measures how quickly you fall asleep and whether you enter into REM sleep.

5. You (or your partner) notice your repetitive leg and foot movements

This may be a sign of a sleep disorder known as Periodic Limb Movement Disorder (PLMD), which is characterized by repetitive leg and foot movement in the form of jerks, muscle twitches, cramping, and flexing during sleep (about every five to 90 seconds). Although it may cause you to wake up, it doesn't always—a common symptom is EDS or fatigue, which causes many to confuse PLMD with insomnia. In many PLMD cases, one’s sleep partner picks up on it first. There are two main types:

  1. Primary
    Primary PLMD is idiopathic, meaning the cause is unknown and the condition appears on its own. 
  2. Secondary
    Secondary PLMD is triggered by a specific cause, such as iron deficiency/anemia, diabetes, over-caffeination, and other sleep disorders such as Restless Leg Syndrome (RLS), narcolepsy, REM sleep behavior disorder, or sleep apnea. It can also present as a side effect of certain medications, including anti-nausea, tricyclic antidepressants, and neuroleptics.  


How PLMD is diagnosed:

First, you will likely undergo a routine physical examination to rule out other causes, followed by a PSG in a sleep lab. 

6. You experience a strong, discomforting urge to move your legs at night

If your legs feel like they’re tingling, itching, aching, and/or burning when you’re trying to fall asleep, that’s a sign of Willis-Ekbom disease, known more commonly as Restless Leg Syndrome (RLS). It affects up to 1 in 10 people at some point during their life, with women twice as likely as men to develop symptoms (6) (particularly pregnant women, 1 out of 5 of whom will experience RLS during their last trimester). (7) Although generally worse at night, RLS can also flare up during inactive periods of the day—especially when in a confirmed space such as a movie theater or train.

Like PLMD, there are two main types of RLS:

  1. Primary
    Primary RLS is idiopathic, meaning the cause is unknown (and may be genetic). It typically begins prior to age 40 and is lifelong. 
  2. Secondary
    Secondary RLS is marked by a sudden onset of symptoms triggered by a specific cause, such as iron deficiency, diabetes, pregnancy, or rheumatoid arthritis. 


How RLS is diagnosed:

Note that RLS is easy to misdiagnose, so it’s important to consult an expert. Because the causes of RLS vary considerably, there isn’t one single diagnostic test. Primary care doctors can usually diagnose the condition based on your medical/family history, a physical examination, and bloodwork. If not, ask for a neurologist referral.

How to find a sleep specialist

Okay, you’ve decided to consult a sleep specialist to take charge of your sleep issues (and overall health). Now comes the tricky part...how to find one and what to look for?

  • How does a physician qualify as a sleep specialist?
    Like primary care physicians, physician specialists complete a residency (typically in internal medicine, neurology, psychiatry, or pediatrics); however, they then go on to a fellowship in sleep medicine and receive board certification from the American Board of Sleep Medicine. In your research, you may also come across the term “otolaryngologists.” This is the official term for ear, nose, and throat (ENT) doctors who can address causes of snoring and OSA and recommend effective oral appliances such as a CPAP machine.

  • Other types of sleep specialists
    In addition to physician sleep specialists, there are also sleep psychologists and other health care professionals specializing in behavioral and mental factors affecting sleep. Behavioral sleep medicine specialists often focus on treating insomnia and problems with sleep wake-rhythm disorders. They also work with sleep medicine physicians to help patients with medical treatments for various sleep disorders like CPAP therapy for OSA. Similar to physician sleep specialists, a behavioral sleep medicine professional must first be licensed as a healthcare professional (e.g. psychologist, social worker, nurse practitioner, etc). They must complete a period of specialized training such as an internship and/or fellowship and pass an exam to become board certified in Behavioral Sleep Medicine by the Board of Behavioral Sleep Medicine. 


In order to find an accredited sleep center, refer to the American Academy of Sleep Medicine’s database as well as the Society of Behavioral Sleep Medicine.

Interested in learning more about reasons you’re so tired even though it seems like you got enough sleep? Allison Siebern, PhD, CBSM weighs in.