“It feels like a case of the flu that won’t go away.”
“I’m tired all of the time.”
“I hurt all over, and I don’t know why.”

For around 2.5 million Americans searching for answers to their agonizing discomfort, symptoms like joint pain, dizziness, severe headaches, memory fog, extreme exhaustion, and restless sleep may point to chronic fatigue syndrome.

Also known as myalgic encephalomyelitis, chronic fatigue syndrome (CFS) is a long-term illness that affects body systems, which often prevents sufferers from engaging in their usual activities. In many cases, the symptoms are so severe that sufferers are bedridden yet cannot get relief through sleep due to sleep problems.

The more we can learn about chronic fatigue syndrome, the faster we can find the right healthcare provider for care and support. Although there is still much to learn about this emerging condition, here are five things we’ve learned about CFS.

1. The Cause of Chronic Fatigue Syndrome Remains Unknown

Doctors haven’t been able to pinpoint a definitive cause of chronic fatigue syndrome. “There’s no single test to confirm a diagnosis of chronic fatigue syndrome,” say Mayo Clinic experts. Moreover, the symptoms often mimic many other health problems, including mental health, sleep disorders, anemia, diabetes, and thyroid problems.

In some cases, doctors are reluctant to identify CFS as the cause of a patient’s symptoms, which regularly last at least six months without relief, since standard testing often fails to show precise results. “Too often, this disease is categorized as imaginary,” says Ron Davis, PhD.
Standard testing checks the patient’s liver, kidney, and heart function while also testing blood and immune cell counts. “All these different tests would normally guide the doctor toward one illness or another, but for chronic fatigue syndrome patients, the results all come back normal,” says Davis.

Davis and other researchers have developed a blood-based test that measures a person’s immune cells’ response to stress. This is one of the first tests that may identify CFS rather than relying on diagnosing the symptoms.

2. The Symptoms Are Consistent among Patients

As researchers learn more about this mysterious and hard-to-detect condition, studies find surprising connections between well-researched conditions—such as hormone imbalance, viral infections, and mental or physical trauma—as well as sleep apnea and their association with CFS.

Medical experts at the Mayo Clinic believe some people have a predisposition that triggers CFS. Some of those potential triggers include the following:
Viral infections: While tests aren’t conclusive, doctors are studying the possibility of a viral infection, such as the Epstein-Barr virus or the human herpesvirus 6, triggering CFS.
Weakened immune system: Patients suffering from symptoms associated with CFS often experience impaired immune systems.
Hormonal imbalances: According to Mayo Clinic studies, people with CFS “sometimes experience abnormal blood levels of hormones produced in the hypothalamus, pituitary glands or adrenal glands.” But further testing is needed.
Physical or emotional trauma: Some people report that they experienced an injury, surgery, or significant emotional stress shortly before their symptoms began.

This list isn’t exclusive. But it is a solid foundation for studying trends in symptoms that occur not only in chronic fatigue cases but also in other conditions like fibromyalgia.

3. CFS Is Sometimes Mistaken for Fibromyalgia

People with fibromyalgia have multiple areas of their body that are painful to touch—called tender points—thought to be due to a problem with how their brain processes pain signals. “Depending on their treatment, approximately a third of those diagnosed with fibromyalgia experience improvement with time,” says Hedy Marks, MPH.

By comparison, those suffering from CFS experience severe, disabling fatigue that does not improve with rest. “You can also suffer from all over as well as joint pain, but your symptoms may seem more like the body aches you get with a cold or flu,” says Marks. CFS symptoms can last from six months to years.

4. Sleep Apnea Is Prevalent among CFS Sufferers

Much like fibromyalgia syndrome, which affects around five million Americans, CFS sufferers often show signs of sleep apnea, both obstructive (OSA) and central. “Fibromyalgia syndrome (FMS) and abnormal sleep breathing commonly go together,” writes Adrienne Dellwo for Verywell Health. “Sleep apnea is considered a possible cause or contributing factor for FMS, and FMS may increase your risk of sleep apnea. Any sleep disorder can make FMS symptoms worse, so treating sleep disorders is often a big help in managing the condition.”

Similarly, experts believe chronic fatigue can be caused by sleep disorders, adding that a sleep study can determine if your rest is being disturbed by conditions such as OSA, restless legs syndrome, or insomnia.

5. Dentists Can Screen for Symptoms of CFS

Suppose that, during a regular screening, your patients complain about acute fatigue, joint pain, headaches, dizziness, and prolonged nights of interrupted sleep that have continued for at least six months. In that case, it’s important to start a discussion about chronic fatigue syndrome and encourage your patient to get tested. Healthcare providers can provide treatment to help manage pain, reduce anxiety, and determine if sleep apnea exacerbates CFS symptoms.

Patients trust their dentist specializing in sleep and airway to provide the best care possible. That means screening not only for oral care but conditions impacting overall wellness and quality of life. For patients who have chronic fatigue syndrome, simply acknowledging their pain is a huge step toward treatment.