Evidence browser

E2 ModerateCohortPEM not requiredLongitudinal

High flow variant postural orthostatic tachycardia syndrome amplifies the cardiac output response to exercise in adolescents.

Pianosi, Paolo T, Goodloe, Adele H, Soma, David et al.·Physiological reports·2014

This study found that about 40% of adolescents with POTS (a condition causing dizziness, fatigue, and rapid heartbeat when standing) have an unusual heart response to exercise: their hearts pump out more blood than expected to keep blood pressure normal. Instead of blood vessels tightening during exercise as they normally do, these patients' blood vessels stay too relaxed, forcing the heart to work harder by pumping more blood to maintain adequate pressure.

Autonomic Nervous System

Increased risk of chronic fatigue syndrome following herpes zoster: a population-based study.

Tsai, S-Y, Yang, T-Y, Chen, H-J et al.·European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology·2014

This study found that people who had shingles (herpes zoster) had a higher risk of developing ME/CFS compared to people who didn't have shingles. Researchers followed thousands of people over several years and found that those with a history of shingles were about 29% more likely to develop chronic fatigue syndrome, suggesting that viral infections like shingles may trigger ME/CFS in some people.

E2 ModerateCohortPEM not requiredObservational

[A chronic fatigue syndrome and blood platelet serotonin levels in patients with multiple sclerosis].

Baĭdina, T V, Akintseva, Iu V, Trushnikova, T N·Zhurnal nevrologii i psikhiatrii imeni S.S. Korsakova·2014

This study looked at fatigue in 60 people with multiple sclerosis (MS) and compared them to 12 healthy people. Researchers measured fatigue using a standardized scale and checked levels of serotonin (a chemical messenger) in blood platelets. They found that nearly 58% of MS patients experienced severe fatigue, and these patients had lower serotonin levels that seemed connected to their MS symptoms.

Short-term effect of aerobic exercise on symptoms in multiple sclerosis and chronic fatigue syndrome: a pilot study.

Learmonth, Yvonne C, Paul, Lorna, McFadyen, Angus K et al.·International journal of MS care·2014

Researchers wanted to see if 15 minutes of moderate cycling exercise would worsen symptoms in people with ME/CFS or MS. They compared 8 people with each condition to 8 healthy volunteers, measuring pain, fatigue, and physical function before exercise and at several time points up to 24 hours after. The good news: a single 15-minute cycling session did not cause lasting increases in pain or worsening of physical function in either patient group.

E2 ModerateCohortPEM not requiredLongitudinal

Daily cytokine fluctuations, driven by leptin, are associated with fatigue severity in chronic fatigue syndrome: evidence of inflammatory pathology.

Stringer, Elizabeth Ann, Baker, Katharine Susanne, Carroll, Ian R et al.·Journal of translational medicine·2013

This study tracked blood samples and fatigue reports from 10 people with ME/CFS and 10 healthy people over 25 days. Researchers found that a hormone called leptin—which controls hunger and immune function—was linked to daily changes in fatigue severity in people with ME/CFS. A computer program analyzing all measured immune markers could correctly identify high fatigue days versus low fatigue days about 78% of the time, suggesting the immune system plays a real role in ME/CFS symptoms.

Immune System

E2 ModerateBehavioralPEM unclearCross-Sectional

Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Symptom Severity: Stress Management Skills are Related to Lower Illness Burden.

Lattie, Emily G, Antoni, Michael H, Fletcher, Mary Ann et al.·Fatigue : biomedicine, health & behavior·2013

This study examined whether learning to manage stress could help people with ME/CFS feel less burdened by their illness, even if their symptoms don't improve. Researchers found that people who felt they had better stress management skills reported lower emotional distress and felt less limited in their daily activities and social life. Importantly, this benefit existed independently of how severe their ME/CFS symptoms were.

E2 ModerateCohortPEM not requiredCase-Control

Early-life hygiene-related factors affect risk of central nervous system demyelination and asthma differentially.

Hughes, A-M, Lucas, R M, McMichael, A J et al.·Clinical and experimental immunology·2013

This study looked at whether early childhood experiences—like having siblings and attending childcare—affect the risk of developing central nervous system demyelination (a condition where the protective coating around nerve fibers becomes damaged). Researchers compared adults with demyelination to healthy controls and found that having younger siblings appeared to protect against demyelination, while the number of older siblings affected asthma risk differently. Interestingly, people with demyelination were more likely to also have chronic fatigue syndrome.

Immune System

E2 ModerateBehavioralPEM not requiredCross-Sectional

Role of childhood adversity in the development of medical co-morbidities associated with bipolar disorder.

Post, Robert M, Altshuler, Lori L, Leverich, Gabriele S et al.·Journal of affective disorders·2013

This study looked at whether difficult experiences in childhood (such as abuse or having parents with mental health problems) are connected to physical health problems in adults with bipolar disorder. Over 900 adults answered questions about their childhood and their current medical conditions. The researchers found that people who experienced more childhood adversity tended to have more medical problems as adults, including chronic fatigue syndrome, fibromyalgia, and several other conditions.

E2 ModerateBehavioralPEM requiredCross-Sectional

Examining the energy envelope and associated symptom patterns in chronic fatigue syndrome: does coping matter?

Brown, Abigail A, Evans, Meredyth A, Jason, Leonard A·Chronic illness·2013

This study looked at whether different groups of ME/CFS patients manage their energy differently and whether coping strategies help them feel better. Researchers found three distinct groups of patients: two groups that fit the energy envelope theory (where staying within your energy limits helps you function better), and one group that was severely limited even though they were trying to stay within their energy limits. Surprisingly, using positive coping strategies didn't improve outcomes for the most impaired group, suggesting that coping alone cannot overcome the severity of ME/CFS.

Could mitochondrial dysfunction be a differentiating marker between chronic fatigue syndrome and fibromyalgia?

Castro-Marrero, Jesús, Cordero, Mario D, Sáez-Francas, Naia et al.·Antioxidants & redox signaling·2013

This study looked at whether problems in the energy-producing parts of cells (mitochondria) might be different between ME/CFS and fibromyalgia, two conditions that cause fatigue and are often confused with each other. Researchers tested blood cells from people with ME/CFS, fibromyalgia, and healthy people, measuring energy-related markers and signs of cellular damage. They found that both conditions showed some mitochondrial problems, but the patterns were different—suggesting mitochondrial dysfunction might help doctors tell these two conditions apart.

Diagnostics

Association of monoamine-synthesizing genes with the depression tendency and personality in chronic fatigue syndrome patients.

Fukuda, Sanae, Horiguchi, Mieko, Yamaguti, Kouzi et al.·Life sciences·2013

This study looked at whether specific genetic variations in two genes (GCH and TH) that help make important brain chemicals were linked to ME/CFS. Researchers compared DNA from ME/CFS patients and healthy controls and gave patients personality and fatigue questionnaires. They found that while these genetic variations weren't directly connected to developing ME/CFS, certain variations were associated with specific personality traits—like how perfectionist or cautious someone tends to be.

E2 ModerateCohortPEM not requiredObservational

Depression in paediatric chronic fatigue syndrome.

Bould, Helen, Collin, Simon M, Lewis, Glyn et al.·Archives of disease in childhood·2013

This study looked at how many young people with ME/CFS also experience depression. Researchers surveyed 542 children aged 12-18 and found that about 29% had depression—much higher than in the general population. Depression was more common in those with worse physical symptoms, higher disability, more pain, and poorer school attendance.

Fatigue heralding multiple sclerosis.

Berger, Joseph R, Pocoski, Jennifer, Preblick, Ronald et al.·Multiple sclerosis (Houndmills, Basingstoke, England)·2013

This study looked at medical records to see how often fatigue appears before someone is diagnosed with multiple sclerosis (MS). Researchers found that about 29% of newly diagnosed MS patients had been labeled with fatigue in the 3 years before their MS diagnosis, often 1–2 years earlier. The findings suggest that persistent fatigue might be an early warning sign of MS, and doctors should carefully evaluate people with unexplained fatigue for possible neurological causes.

Diagnostics

E2 ModerateCohortPEM unclearObservational

Altered functional B cell subset populations in patients with chronic fatigue syndrome compared to healthy controls.

Bradley, A S, Ford, B, Bansal, A S·Clinical and experimental immunology·2013

This study looked at different types of B cells (immune cells that help fight infection) in people with ME/CFS compared to healthy people. Researchers found that ME/CFS patients had more immature B cells and fewer fully developed B cells than healthy controls, suggesting their immune system might not be developing B cells normally. This finding is interesting because a drug that removes B cells helped some ME/CFS patients improve.

Immune System

Lack of evidence for retroviral infections formerly related to chronic fatigue in Spanish fibromyalgia patients.

Oltra, Elisa, García-Escudero, María, Mena-Durán, Armando Vicente et al.·Virology journal·2013

Researchers tested whether two viruses previously thought to be linked to ME/CFS and fibromyalgia were actually present in Spanish patients with these conditions. They found no reliable evidence that either virus was present in patient samples, and concluded that earlier positive results were likely due to contamination in the laboratory rather than genuine infections.

E2 ModeratePEM not requiredRegistry-Resource

Cholecystectomy and clinical presentations of gastroparesis.

Parkman, Henry P, Yates, Katherine, Hasler, William L et al.·Digestive diseases and sciences·2013

This study looked at 391 patients with gastroparesis (a condition where the stomach empties food slowly) to see if those who had their gallbladder removed had different symptoms than those who hadn't. They found that patients who had gallbladder surgery experienced more severe upper abdominal pain and retching, but less constipation. Interestingly, patients with prior gallbladder removal also had more other health conditions, including chronic fatigue syndrome and fibromyalgia.

E2 ModerateCohortPEM requiredObservational

Exercise challenge in Gulf War Illness reveals two subgroups with altered brain structure and function.

Rayhan, Rakib U, Stevens, Benson W, Raksit, Megna P et al.·PloS one·2013

This study looked at Gulf War veterans who experience post-exertional malaise (PEM)—a worsening of symptoms after physical activity—and compared them to healthy controls. Researchers used brain imaging before and after exercise tests and found that Gulf War Illness patients fell into two distinct groups: one with heart rate problems and one with increased pain sensitivity. Both groups showed different patterns of brain structure changes and how their brains responded to exercise, while healthy controls showed no such changes.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Influence of symptom expectancies on stair-climbing performance in chronic fatigue syndrome: effect of study context.

Heins, Marianne, Knoop, Hans, Nijs, Jo et al.·International journal of behavioral medicine·2013

This study looked at how ME/CFS patients' expectations about getting worse after physical activity affect how they actually perform during that activity. Researchers had 49 patients climb stairs while measuring how long it took and how their heart rate changed. They found that patients who expected to feel more fatigued after climbing took longer to complete the task, even after accounting for their initial fatigue level. Worry about symptoms and catastrophic thinking about their condition appeared to play a role in these expectations.

Contrasting Chronic Fatigue Syndrome versus Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Jason, Leonard A, Brown, Abigail, Evans, Meredyth et al.·Fatigue : biomedicine, health & behavior·2013

This study compared two different sets of diagnostic criteria used to identify ME/CFS patients. Researchers found that the Canadian criteria are stricter and identify patients who tend to be more severely affected, while the older Fukuda criteria cast a wider net. This suggests that the criteria used to diagnose someone with ME/CFS can significantly affect who gets identified as having the condition.

Diagnostics