Maximal oxygen uptake and lactate metabolism are normal in chronic fatigue syndrome

Abstract:

PURPOSE: Previous studies in chronic fatigue syndrome (CFS) have reported reductions in maximal oxygen uptake (VO(2max)), yet often the testing procedures have not followed accepted guidelines, and gender data have been pooled. The present study was undertaken to reevaluate exercise capacity in CFS patients by using “gold standard” maximal exercise testing methodology and stratifying results on a gender basis.

METHODS: Sixteen male and 17 female CFS patients and their gender-, age-, and mass-matched sedentary controls performed incremental exercise to volitional exhaustion on a stationary cycle ergometer while selected cardiorespiratory and metabolic variables were measured.

RESULTS: VO(2max) in male CFS patients was not different from control values (CFS: 40.5 +/- 6.7; controls: 43.3 +/- 8.6; mL x kg(-1) x min(-1)) and was 96.3 +/- 17.9% of the age-predicted value, indicating no functional aerobic impairment (3.7 +/- 17.9%). In female CFS patients, VO(2max) was lower than control values (CFS: 30.0 +/- 4.7; controls: 34.2 +/- 5.6; mL x kg(-1) x min(-1), P = 0.002), but controls were higher than the age-predicted value (112.6 +/- 15.4%, P = 0.008) whereas the CFS patients were 101.2 +/- 20.4%, indicating no functional aerobic impairment (-1.2 +/- 20.4%). Maximal heart rate (HR(max)) in male CFS patients was lower than their matched controls (CFS: 184 +/- 10; controls: 192 +/- 12; beats x min(-1); P = 0.016) but was 99.1 +/- 5.5% of their age-predicted value. In female CFS patients, HR(max) was not different from controls (CFS: 183 +/- 11; controls: 186 +/- 10; beats x min(-1)) and was 98.9 +/- 5.1% of the age-predicted value. The VO(2) at the lactate threshold (LT) in each gender group, whether expressed in mL x kg(-1) x min(-1) or as a percentage of VO(2max), was not different between CFS patients and controls.

CONCLUSIONS: In contrast to most previous reports, the present study found that VO(2max), HR(max), and the LT in CFS patients of both genders were not different from the values expected in healthy sedentary individuals of a similar age.

Comment in:

Chronic fatigue syndrome, deconditioning, and graded exercise therapy. [Med Sci Sports Exerc. 2002]

VO2max and lactate production are not normal in all patients with chronic fatigue. [Med Sci Sports Exerc. 2002]

 

Source: Sargent C, Scroop GC, Nemeth PM, Burnet RB, Buckley JD. Maximal oxygen uptake and lactate metabolism are normal in chronic fatigue syndrome. Med Sci Sports Exerc. 2002 Jan;34(1):51-6. http://www.ncbi.nlm.nih.gov/pubmed/11782647

 

Chronic fatigue report delayed as row breaks out over content

The government’s long awaited report on the treatment of chronic fatigue syndrome could be in jeopardy after four key members resigned from the working group.

The move throws doubt on the validity of the report, which was due to be published in the first week of January. As the BMJ went to press, the chief medical officer, Liam Donaldson, had postponed its launch on 4 January 2002.

A total of 10 people from the original working group have resigned for various reasons since it was set up in 1998. The most recent resignations were highlighted in a written question by the Countess of Mar to health minister Lord Hunt on 17 December.

Two psychiatrists, a public health doctor, and a nurse therapist have resigned, saying that the report plays down the psychological and social aspects of the condition and concentrates on a medical model. Two patients are understood to have also resigned recently.

The group was set up to consider how best the NHS could care for people with the syndrome, also known as myalgic encephalomyelitis or “ME.”

But with so little still known about what causes the syndrome, how to diagnose it, and how best to treat it, it is understood that the report fails to provide the straightforward answers doctors may have hoped for.

You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121974/

 

Source: Eaton L. Chronic fatigue report delayed as row breaks out over content. BMJ. 2002 Jan 5;324(7328):7. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121974/ (Full article)

 

Chronic fatigue and anxiety/depression: a twin study

Abstract:

BACKGROUND: Up to three-quarters of patients with fatigue syndromes have comorbid mood or anxiety disorders, suggesting that chronic fatigue is a forme fruste of anxiety or depressive states.

AIMS: To establish whether the association of chronic fatigue with psychological distress is causal or due to a common genetic or environmental factor.

METHOD: 69 monozygotic (MZ) and 31 dizygotic (DZ) female twin pairs, with only one co-twin reporting at least 6 months of fatigue, completed questions on fatigue, the General Health Questionnaire (GHQ) and a structured psychiatric interview. We examined the effects of three progressively more stringent definitions of chronic fatigue on four GHQ sub-scales.

RESULTS: Fatigued MZ and DZ twins by all definitions were significantly more depressed, anxious, somatically preoccupied and socially dysfunctional than their non-fatigued co-twins. Intrapair differences were similar in DZ and MZ twins, but non-significant differences were observed for the somatic symptoms and anxiety/insomnia sub-scales.

CONCLUSIONS: In this sample, chronic fatigue and psychological distress are strongly associated without evidence for genetic covariation, implying that the association is environmental, or due to overlapping definitions. Any genetic covariation missed is likely to involve anxiety rather than depression.

 

Source: Roy-Byrne P, Afari N, Ashton S, Fischer M, Goldberg J, Buchwald D. Chronic fatigue and anxiety/depression: a twin study. Br J Psychiatry. 2002 Jan;180:29-34. http://www.ncbi.nlm.nih.gov/pubmed/11772848

 

Neurobehavioral deficits associated with chronic fatigue syndrome in veterans with Gulf War unexplained illnesses

Abstract:

Gulf War unexplained illnesses (GWUI) are a heterogeneous collection of symptoms of unknown origin known to be more common among veterans of the Gulf War than among nonveterans. In the present study we focused on one of these unexplained illnesses.

We tested the hypothesis that in a sample of Persian Gulf War veterans chronic fatigue syndrome (CFS) was associated with cognitive deficits on computerized cognitive testing after controlling for the effects of premorbid cognitive differences. We obtained Armed Forces Qualification Test (AFQT) data acquired around the date of induction into the military on 94 veterans of the Gulf War, 32 with CFS and 62 healthy controls. Controls performed better than participants diagnosed with CFS on the AFQT. Cognitive deficits were associated with CFS on 3 of 8 variables after the effect of premorbid AFQT scores was removed with ANCOVA.

 

Source: Binder LM, Storzbach D, Campbell KA, Rohlman DS, Anger WK; Members of the Portland Environmental Hazards Research Center. Neurobehavioral deficits associated with chronic fatigue syndrome in veterans with Gulf War unexplained illnesses. J Int Neuropsychol Soc. 2001 Nov;7(7):835-9. http://www.ncbi.nlm.nih.gov/pubmed/11771626

 

A biochemical analysis of people with chronic fatigue who have Irlen Syndrome: speculation concerning immune system dysfunction

Abstract:

This study investigated the biological basis of visual processing disabilities in adults with Chronic Fatigue Syndrome. The study involved 61 adults with symptoms of Chronic Fatigue Syndrome who were screened for visual processing problems (Irlen Syndrome) and divided into two groups according to the severity of symptoms of Irlen Syndrome.

Significant variations were identified in blood lipids and urine amino and organic acids of the two groups, which may be indicative of activation of the immune system due to some infective agent. It was suggested that metabolic profiling may help the development of more valid diagnostic categories and allow more investigation of immune system dysfunction as a possible causal factor in a range of learning and behaviour disorders.

 

Source: Robinson GL, McGregor NR, Roberts TK, Dunstan RH, Butt H. A biochemical analysis of people with chronic fatigue who have Irlen Syndrome: speculation concerning immune system dysfunction. Percept Mot Skills. 2001 Oct;93(2):486-504. http://www.ncbi.nlm.nih.gov/pubmed/11769907

 

Chronic fatigue syndrome

Comment on:

Chronic fatigue syndrome. [Br J Gen Pract. 2001]

Frequency of attendance in general practice and symptoms before development of chronic fatigue syndrome: a case-control study. [Br J Gen Pract. 2001]

 

Professor Murdoch in the September BJGP 1 uses his study of Down’s syndrome,2 which demonstrated that mothers had an increased number of reported illnesses in the year before the birth, to undermine our interpretation of the findings in our chronic fatigue syndrome (CFS) study in the July BJGP. 3 He asks why anyone should believe CFS is caused by behavioural factors.

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1314178/pdf/11766858.pdf

 

Source: Hamilton W. Chronic fatigue syndrome. Br J Gen Pract. 2001 Dec;51(473):1015. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1314178/pdf/11766858.pdf (Full comment)

 

Symptom factor analysis, clinical findings, and functional status in a population-based case control study of Gulf War unexplained illness

Abstract:

Few epidemiological studies have been conducted that have incorporated clinical evaluations of Gulf War veterans with unexplained health symptoms and healthy controls. We conducted a mail survey of 2022 Gulf War veterans residing in the northwest United States and clinical examinations on a subset of 443 responders who seemed to have unexplained health symptoms or were healthy. Few clinical differences were found between cases and controls.

The most frequent unexplained symptoms were cognitive/psychological, but significant overlap existed with musculoskeletal and fatigue symptoms. Over half of the veterans with unexplained musculoskeletal pain met the criteria for fibromyalgia, and a significant portion of the veterans with unexplained fatigue met the criteria for chronic fatigue syndrome. Similarities were found in the clinical interpretation of unexplained illness in this population and statistical factor analysis performed by this study group and others.

 

Source: Bourdette DN, McCauley LA, Barkhuizen A, Johnston W, Wynn M, Joos SK, Storzbach D, Shuell T, Sticker D. Symptom factor analysis, clinical findings, and functional status in a population-based case control study of Gulf War unexplained illness. J Occup Environ Med. 2001 Dec;43(12):1026-40. http://www.ncbi.nlm.nih.gov/pubmed/11765674

 

Cognitive behavioral therapy and fasting therapy for a patient with chronic fatigue syndrome

Abstract:

Cognitive behavioral therapy temporarily alleviated symptoms of a chronic fatigue syndrome patient but the anxiety about rehabilitation into work became stronger and his symptoms worsened. This patient was successfully rehabilitated by fasting therapy. Natural killer cell activity and serum acylcarnitine levels recovered after fasting therapy. Though fasting therapy transiently increased physical and mental subjective symptoms, the patient gained self-confidence by overcoming difficulties after fasting therapy. A combination of cognitive behavioral therapy and fasting therapy is promising as a treatment for chronic fatigue syndrome.

 

Source: Masuda A, Nakayama T, Yamanaka T, Hatsutanmaru K, Tei C. Cognitive behavioral therapy and fasting therapy for a patient with chronic fatigue syndrome. Intern Med. 2001 Nov;40(11):1158-61. https://www.jstage.jst.go.jp/article/internalmedicine1992/40/11/40_11_1158/_article (Full article)

 

Blood volume and its relation to peak O(2) consumption and physical activity in patients with chronic fatigue

Abstract:

Individuals with chronic fatigue syndrome (CFS) experience a number of somatic complaints including severe, disabling fatigue, and exercise intolerance. We hypothesized that hypovolemia, through its interaction with central hemodynamics, would contribute to the exercise intolerance associated with this disorder. We examined blood volume, peak aerobic power, habitual physical activity, fatigue level, and their interrelations to understand the physiological basis of this disorder.

Seventeen patients who met the Centers for Disease Control criteria for CFS and 17 age-matched controls participated in the study. Blood volume was assessed using a single bolus injection of Evans blue dye. Peak oxygen consumption was measured during exercise on an upright cycle ergometer. Supine cardiac output and stroke volumes were measured using CO(2) rebreathing. Questionnaires were used to assess habitual physical activity and fatigue.

Patients displayed a trend for a 9% lower blood volume (58.3 +/- 2.1 vs. 64.2 +/- 2.5 ml/kg, P = 0.084) and had a 35% lower peak oxygen consumption (22.0 +/- 1.2 vs. 33.6 +/- 1.9 ml/kg, P < 0.001). These two variables were highly related within the patients (r = 0.835, P < 0.001) and the controls (r = 0.850, P < 0.001). Peak ventilation and habitual physical activity were significantly lower in the patients. Fatigue level was not related to any of the measured physiological parameters within the CFS group.

In conclusion, individuals with CFS have a significantly lower peak oxygen consumption and an insignificant trend toward lower blood volume compared with controls. These variables were highly related in both subject groups, indicating that blood volume is a strong physiological correlate of peak oxygen consumption in patients with CFS.

 

Source: Farquhar WB, Hunt BE, Taylor JA, Darling SE, Freeman R. Blood volume and its relation to peak O(2) consumption and physical activity in patients with chronic fatigue. Am J Physiol Heart Circ Physiol. 2002 Jan;282(1):H66-71. http://ajpheart.physiology.org/content/282/1/H66.long (Full article)

 

Predictions and associations of fatigue syndromes and mood disorders that occur after infectious mononucleosis

Abstract:

BACKGROUND: Certain infections can trigger chronic fatigue syndromes (CFS) in a minority of people infected, but the reason is unknown. We describe some factors that predict or are associated with prolonged fatigue after infectious mononucleosis and contrast these factors with those that predicted mood disorders after the same infection.

METHODS: We prospectively studied a cohort of 250 primary-care patients with infectious mononucleosis or ordinary upper-respiratory-tract infections until 6 months after clinical onset. We sought predictors of both acute and chronic fatigue syndromes and mood disorders from clinical, laboratory, and psychosocial measures.

FINDINGS: An empirically defined fatigue syndrome 6 months after onset, which excluded comorbid psychiatric disorders, was most reliably predicted by a positive Monospot test at onset (odds ratio 2.1 [95% CI 1.4-3.3]) and lower physical fitness (0.35 [0.15-0.8]). Cervical lymphadenopathy and initial bed rest were associated with, or predicted, a fatigue syndrome up to 2 months after onset. By contrast, mood disorders were predicted by a premorbid psychiatric history (2.3 [1.4-3.9]), an emotional personality score (1.21 [1.11-1.35]), and social adversity (1.7 [1.0-2.9]). Definitions of CFS that included comorbid mood disorders were predicted by a mixture of those factors that predicted either the empirically defined fatigue syndrome or mood disorders.

INTERPRETATION: The predictors of a prolonged fatigue syndrome after an infection differ with both definition and time, depending particularly on the presence or absence of comorbid mood disorders. The particular infection and its consequent immune reaction may have an early role, but physical deconditioning may also be important. By contrast, mood disorders are predicted by factors that predict mood disorders in general.

 

Source: White PD, Thomas JM, Kangro HO, Bruce-Jones WD, Amess J, Crawford DH, Grover SA, Clare AW. Predictions and associations of fatigue syndromes and mood disorders that occur after infectious mononucleosis. Lancet. 2001 Dec 8;358(9297):1946-54. http://www.ncbi.nlm.nih.gov/pubmed/11747919