What Is Chronic Fatigue Syndrome?

Chronic fatigue syndrome, or CFS, is unexplained, persistent fatigue that isn’t helped by rest and can be made worse by extra activity. It’s also called systemic exertion intolerance disease (SEID), and myalgic encephalomyelitis (ME):

  • Myalgic: Aches in muscles.
  • Encephalomyelitis: Inflammation of the central nervous system.

When inflammation is present with fatigue, the condition is called ME, but when there’s no inflammation, it’s known as CFS.

CFS can affect anyone but is most common in women between the ages of 30 and 50. Experts believe that one of the reasons for this statistic is that women are more likely to report symptoms and seek help.

There is a common misconception that CFS is “just being tired,” according to Zaher Nahle, PhD, MPA, the Chief Scientific Officer (CSO) and Vice President for Research at Solve ME/CFS Initiative. However, Dr. Nahle explained, “ME/CFS is actually characterized by an entire cluster of symptoms, including debilitating inability to function physically or cognitively as well as other complex symptoms.” Dr. Nahle said CFS/ME patients might also experience orthostatic intolerance, which is the development of symptoms while standing up that subside when reclining, or have an energy crash after participating in simple activities like walking, driving, or taking a shower.

Stages and Types of Chronic Fatigue Syndrome

There are three stages of chronic fatigue syndrome:

  • Illness: The stage in which conditions arise to trigger the syndrome, such as infection or increased stress.
  • Stabilization: The stage in which the initial condition is resolving, but the fatigue is still persistent.
  • Healing:  The phase where the individual is applying treatment strategies that are helping.

Chronic fatigue syndrome varies in the way it presents from person to person, but generally, there are several levels of severity:

  • Mild: When your CFS is mild, you can still work and do simple domestic duties. However, you must reduce the time you spend on activities, and you may tend to avoid unnecessary social engagements to conserve energy. Sometimes you will find yourself taking a bit of time off work.
  • Moderate: When CFS is moderate, you notice difficulties with sleeping, and you’ll need more time away from work or school. The condition limits your ability to participate in daily activities, and you will need to seek more rest.
  • Severe: At the severe end of CFS, the condition impacts your cognition, and you become sensitive to light and sound. You spend most of your time bedridden at home. You need help with day-to-day activities and may not be able to move around much.

Symptoms and Causes of Chronic Fatigue Syndrome

Experts don’t know the exact cause of chronic fatigue syndrome, although they theorize that there may be a variety of factors that can lead to it. Viral infections could be one culprit; some people develop CFS after having a virus such as human herpes 6, mouse leukemia, or Epstein-Barr. Since many CFS sufferers also have irregularities with their immune system, there appears to be a link between the disorder and problems with the immune system. Hormonal imbalances are also suspect.

“The hallmark [symptom] is the inability to sleep despite being exhausted,” said Jacob Teitelbaum, MD, a board-certified internist, and an expert in the medical fields of chronic fatigue syndrome, fibromyalgia, sleep, and pain. “Dozens of other common symptoms are present including ‘brain fog,’ widespread pain, gut and sinus problems, and a host of others,” Dr. Teitelbaum added.

Other typical symptoms include:

  • Fatigue
  • Sore throat
  • Memory loss
  • Difficulties concentrating
  • Enlarged lymph nodes
  • Headaches
  • Extreme exhaustion following mental or physical exertion

Prevention and Risks of Chronic Fatigue Syndrome

Prevention of chronic fatigue syndrome involves lifestyle modifications designed to maximize the quality of your rest and reduce your stress level. Suggestions include:

  • Keep a journal to track your energy level to see if you can identify any useful patterns or connections.
  • Don’t overdo it when you have energy: pace yourself so that you don’t end up overtired.
  • Maintain a consistent schedule for going to bed at night and waking up in the morning.
  • Practice good sleep habits, such as reducing light and sound disturbances, avoiding caffeine and keeping your bedroom at a comfortable temperature.

Those who are at highest risk of developing chronic fatigue syndrome include:

  • Individuals in their 30s, 40s, and 50s
  • Women
  • People who have difficulties with stress management

Diagnosis and Tests of Chronic Fatigue Syndrome

“Many patients struggle for years before being diagnosed,” said Dr. Nahle. “Because ME/CFS symptoms overlap with many other conditions, including fibromyalgia, IBS, and orthostatic intolerance, determining which illnesses are present can be difficult. Patients often receive a diagnosis for multiple conditions if not seen by ME/CFS specialist.”

However, it is hopefully becoming easier for doctors to diagnose ME/CFS accurately because The Institute of Medicine (IOM) published a concise and easy clinical diagnostic criteria for ME/CFS in 2015.

Diagnosticians identify chronic fatigue syndrome by process of elimination. There is no single test to determine the presence of CFS; instead, your doctor will rule out other conditions that could be causing your fatigue.

Your doctor will assess your symptoms and conduct or order tests that may include:

  • Physical exam
  • Blood work (to rule out conditions such as anemia, diabetes, hypothyroidism, and lung disease)
  • Polysomnography (to check for obstructive sleep apnea)
  • Sleep disorder tests (to see if you have insomnia)
  • Chest x-ray and electrocardiogram (to rule out heart disease)
  • Pulse oximetry, pulmonary function tests, chest x-rays, bronchoscopy, chest CT, and biopsy (to check for lung disease)
  • Psychological assessment (to see if your fatigue might be from conditions such as depression or anxiety)

If the tests don’t point to a conclusive cause of your persistent low energy, your doctor may give you a diagnosis of chronic fatigue syndrome.

Treatment, Procedures, and Medication for Chronic Fatigue Syndrome

“Without effective treatment, [CFS] can be devastating, often destroying their ability to make a living and stressing their personal relationships,” Dr. Teitelbaum said. “There is no single pharmaceutical or surgical ‘magic bullet,’” for CFS, he added. Usually, it is necessary to incorporate many different treatment approaches for patients to find relief from CFS symptoms.

Doctors treat the main symptoms of CFS individually, and there are many therapies “that help alleviate symptoms, increase function, and allow people with ME/CFS to engage in activities of daily living,” said Dr. Nahle. “Sleep problems, pain, heart rate irregularities, gastrointestinal difficulties, allergies, and depression are some of the symptoms that can potentially be relieved by treatment.”

Here are some common types of treatment that can help patients with CFS/ME:

  • Counseling can help treat chronic fatigue syndrome by making you feel more in control of the events and situations in your life, which will reduce your stress and make you feel less tired. Learn how to find the right counselor for your needs.
  • Physical therapy can introduce graded exercise, which is a way of slowly beginning healthy activity in a way that won’t make you more tired. For example, your physical therapist can recommend a small and easy daily starting point, such as stretching or range of motion exercises.
  • Medication can be used to treat associated conditions which will ease the impact of your chronic fatigue syndrome. For example, you may also suffer from depression that can make you even more tired, which your doctor can treat pharmaceutically.

According to Dr. Nahle, alternative therapies such as acupuncture, hydrotherapy, yoga, tai chi, and massage therapy may also help some individuals with CFS to manage their symptoms.

Healthy Lifestyle Tips

Lifestyle can influence the outcome of many conditions, and chronic fatigue syndrome is no exception. Your medical care team can help you determine which healthy activities will be right for you.

“Individual experience of symptoms is differential, but there are some lifestyle changes that can have a positive functional impact on a broad swath of patients,” said Dr. Nahle.

Graded exercise, or activity that starts with a very low intensity but increases gradually over time, may help to boost your energy by circulating nutrients throughout your system. Stress reduction techniques improve your morale and help you sleep better. Social contact with those similarly afflicted through a support group can also help.

“Symptom management strategies include tracking activity throughout the day and pacing one’s activities to stay within an energy envelope for any given day,” Dr. Nahle suggested. “Breaking up tasks into manageable portions gives patients more control over their lives and helps them avoid ‘crashes.’”

Food- and Nutrition-Based Approaches to Prevention/Management

“Many [CFS] patients suffer from GI symptoms and food sensitivities, but establishing a workable diet is highly individualized,” Dr. Nahle said. “Supplements, such as Vitamin B12, essential fatty acids, and antioxidants, have been observed by patients and clinicians to help in some cases, but not in others.”

A healthy diet can adequately nourish your body and fight infection. The way you eat can affect your energy level, so pay attention to what you eat to help treat chronic fatigue syndrome. Talk to your doctor about an individualized nutrition plan that is right for your needs. Changes you can make that may help include:

  • Try an anti-inflammatory diet (eliminate refined sugar, processed meat, and fried foods, while consuming more anti-inflammatory items like fish oil).
  • Make sure you drink enough fluids.
  • Reduce caffeine consumption.
  • Avoid big meals.
  • Eat more vegetables.
  • Eat fewer processed foods.
  • Include healthy fat items in your diet, such as avocados, walnuts, and trout.

What Type of Doctors to See

Your primary care doctor will set the wheels in motion to help you get a diagnosis of what causes your fatigue. Since there is no single test to diagnose chronic fatigue syndrome, determining if this is what you have will involve testing to rule out other conditions. As a result, you may end up in the capable hands of multiple clinicians, including:

  • Psychologist
  • Psychiatrist
  • Cardiologist
  • Nutritionist
  • Rheumatologist
  • Pulmonary Specialist
  • Nurse
  • Lab technician


Chronic fatigue syndrome can impact many aspects of your life because of the way that it affects your energy level. Your family doctor will offer the essential information to help you manage your chronic fatigue syndrome symptoms. Your doctor can also refer you to other clinicians for appropriate care and to get you on the path to reclaiming your energy.

Expert Contributors:

Jacob Teitelbaum, MD has specialized in treating chronic pain, chronic fatigue, and fibromyalgia for many decades. He is the lead author of four studies on effective treatment for fibromyalgia and chronic fatigue syndrome. Helping people to get their lives back is his passion. Dr. Teitelbaum practices in Kailua-Kona, Hawaii.

Zaher Nahle, Ph.D., MPA, is the Chief Scientific Officer (CSO) to Solve ME/CFS Initiative. A scientist with interdisciplinary training in biomedical research and public administration, Dr. Nahle has won several awards, such as the Army Breast Cancer Fellowship Award, the American Heart Association Career Development Award, and the National Priorities Research Award.