Category: Exercise

Exercise responses in the chronic fatigue syndrome. Objective assessment of study is difficult without knowledge of data

Comment on: Exercise responses and psychiatric disorder in chronic fatigue syndrome. [BMJ. 1995]

 

EDITOR,-In their study of exercise responses and psychiatric disorder in the chronic fatigue syndrome Russell J M Lane and colleagues claim to have detected abnormal lactate responses to subanaerobic threshold exercise in 31 of 96 patients. As no data are offered to support this statement, however, objective assessment of the validity of their findings is difficult.

The authors’ definition of an abnormal response is “lactate concentrations exceeding the upper 99% reference limit for normal control subjects at two or more time points.” However, only three samples were taken (before, immediately after, and 30 minutes after exercise), and a raised lactate concentration in the sample obtained before exercise began cannot be described as an abnormal response to exercise. Neither the method used to measure lactate nor its precision is given; assessment of the importance of the “abnormal” lactate concentrations could not be guessed at without this information, even if the authors had given details of the patients’ concentrations.

You can read the full comment along with the authors’ reply here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551191/pdf/bmj00618-0070a.pdf

 

Source: Hutchison AS. Exercise responses in the chronic fatigue syndrome. Objective assessment of study is difficult without knowledge of data. BMJ. 1995 Nov 11;311(7015):1304. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551191/pdf/bmj00618-0070a.pdf

 

Exercise responses and psychiatric disorder in chronic fatigue syndrome

Comment in: Exercise responses in the chronic fatigue syndrome. Objective assessment of study is difficult without knowledge of data. [BMJ. 1995]

 

Fatigue, exercise intolerance, and myalgia are cardinal symptoms of the chronic fatigue syndrome, but whether they reflect neuromuscular dysfunction or are a manifestation of depression or other psychiatric or psychological disorders diagnosed in a high proportion of fatigued patients in the community is unclear.’ In previous studies patients with the chronic fatigue syndrome showed exercise intolerance in incremental exercise tests, which seemed to be related to an increased perception of effort; also, blood lactate concentrations in some patients tended to increase more rapidly than normal at low work rates, implying inefficient aerobic muscle metabolism.2 We examined venous blood lactate responses to exercise at a work rate below the anaerobic threshold in relation to psychiatric disorder.

You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2550606/pdf/bmj00607-0028.pdf

 

Source: Lane RJ, Burgess AP, Flint J, Riccio M, Archard LC. Exercise responses and psychiatric disorder in chronic fatigue syndrome. BMJ. 1995 Aug 26;311(7004):544-5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2550606/pdf/bmj00607-0028.pdf

 

Chronic fatigue syndrome and fibromyalgia

Comment on: Population study of tender point counts and pain as evidence of fibromyalgia. [BMJ. 1994]

 

EDITOR,-The relation between muscle pain, tender points, the chronic fatigue syndrome, and fibromyalgia are complex, and simplistic answers are inappropriate. In their paper Peter Croft and colleagues extrapolate their results to make two statements that I believe to be incorrect.’

My conclusions are based on 100 consecutive patients seen at Raigmore Hospital NHS Trust, who fulfilled precise definitions of the chronic fatigue syndrome 2 or fibromyalgia.3 The importance of this definition of the syndrome is that it has the same three month cut off for length of illness as fibromyalgia.3 Of the 100 patients, 99 (74 women, 25 men) had the chronic fatigue syndrome and one (a woman) had fibromyalgia. Of the patients with the chronic fatigue syndrome, 63 had muscle pain and 28 had tender points on examination, 23 had both, and five had no muscle pain but tender points. These results do not support the authors’ statement that the reason why fibromyalgia is not more common in Britain has been the acceptability of the chronic fatigue syndrome as an alternative diagnosis.

The authors also say that it is “inappropriate to define an entity as fibromyalgia.” As a clinical virologist, I strongly disagree with this as the distribution and number of tender points in fibromyalgia are different from those in the chronic fatigue syndrome, and the management of the two conditions is different.4 Patients with the syndrome should be advised not to increase their activities gradually until they feel 80% of normal,5 whereas patients with fibromyalgia may benefit from a regimen of increasing activity.4

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2541601/pdf/bmj00468-0067b.pdf

 

Source: Ho-Yen DO. BMJ. Chronic fatigue syndrome and fibromyalgia. 1994 Dec 3;309(6967):1515. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2541601/

 

Lactate responses to exercise in chronic fatigue syndrome

Comment on: Exercise performance and fatiguability in patients with chronic fatigue syndrome. [J Neurol Neurosurg Psychiatry. 1993]

 

We were interested to read the recent account of exercise characteristics in patients with chronic fatigue syndrome by Gibson et al,’ which concluded that there was no abnormality of neuromuscular function in this condition. Patients reached the limits of exercise tolerance at lower heart rates than controls during incremental exercise to exhaustion but their peak work rates and duration of exercise did not differ significantly from the control group, although the total work done (the product of these variables) would appear to have been less; the authors had previously reported that patients with this condition showed a reduction in maximal work rate achieved in such tests.2 Despite this, plasma lactate levels at the end of exercise were as high in the patients as the controls.

In an earlier study using incremental exercise on a treadmill, Riley et a13 had found higher heart rates and increased lactate levels compared with normal controls at submaximal work rates but similarly noted no differences at peak exercise.

We have found that a proportion of patients with chronic fatigue syndrome exhibit abnormally raised lactate levels following steady state exercise at work rates below the anerobic threshold, corresponding to roughly half the peak work rates achieved in the incremental test paradigm.4 It is thus possible that lactate levels in some patients increase more rapidly than normal at lower work rates.

The cause of this apparent ‘left shift’ of the anaerobic threshold is unclear. Neither we nor Gibson et al 2 found evidence of “deconditioning” in terms of cardiac responses to exercise in our patients, and phosphorus spectroscopy of muscle in the syndrome has shown no consistent disturbance of muscle energy metabolism.5 The phenomenon may be of significance in the pathogenesis of “fatigue” in some patients, and it may be premature to conclude that neuromuscular function in all patients is normal, or that the “fatigue” is exclusively “central” in origin. Indeed, it may be presumptuous to consider chronic fatigue syndrome as a unitary entity.

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1072952/pdf/jnnpsyc00035-0134b.pdf

 

Source: Lane RJ, Woodrow D, Archard LC. Lactate responses to exercise in chronic fatigue syndrome. J Neurol Neurosurg Psychiatry. 1994 May;57(5):662-3. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1072952/

 

Effects of mild exercise on cytokines and cerebral blood flow in chronic fatigue syndrome patients

 

Abstract:

Chronic fatigue syndrome (CFS) is an idiopathic disorder characterized by fatigue that is markedly exacerbated by physical exertion. In the present study, we tested the hypothesis that mild exercise (walking 1 mph [1 mile = 1.609 km] for 30 min) would provoke serum cytokine and cerebral blood flow abnormalities of potential pathogenic importance in CFS.

Interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha were nondetectable in sera of CFS patients (n = 10) and healthy control subjects (n = 10) pre- and postexercise. At rest, serum transforming growth factor beta (TGF-beta) levels were elevated in the CFS group compared with the control group (287 +/- 18 versus 115 +/- 5 pg/ml, respectively; P < 0.01). Serum TGF-beta and cerebral blood flow abnormalities, detected by single-photon emission-computed tomographic scanning, were accentuated postexercise in the CFS group.

Although these findings were not significantly different from those in the control group, the effect of exercise on serum TGF-beta and cerebral blood flow appeared magnified in the CFS patients. Results of this study encourage future research on the interaction of physical exertion, serum cytokines, and cerebral blood flow in CFS that will adopt a more rigorous exercise program than the one used in this study.

 

Source: Peterson PK, Sirr SA, Grammith FC, Schenck CH, Pheley AM, Hu S, Chao CC. Effects of mild exercise on cytokines and cerebral blood flow in chronic fatigue syndrome patients. Clin Diagn Lab Immunol. 1994 Mar;1(2):222-6. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC368231/

You can read the full article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC368231/pdf/cdli00002-0112.pdf

 

Cytokine production and fatigue in patients with chronic fatigue syndrome and healthy control subjects in response to exercise

Abstract:

We have studied the relationship between the cytokine production induced in vivo by prolonged isometric exercise and the symptom complex marked by fatigue in patients with chronic fatigue syndrome (CFS).

Twelve male patients and 13 matched male control subjects undertook an isometric hand-grip exercise protocol utilizing dynamometers. Subjects undertook 30 minutes of exercise, for which the target force was set at 40% of the maximal voluntary contraction and the duty cycle was 50%. Prior to, during, and for 24 hours following the exercise, blood samples were collected and assayed for the presence of cytokines, including interferon-gamma and interferon-alpha, interleukin-1 beta, and tumor necrosis factor-alpha. At those times subjects also completed the Profile of Mood States (POMS) questionnaire, which served as a measure of changes in subjective fatigue.

No significant alteration in the level of any of the cytokines in the plasma of patients or control subjects was detected before, during, or after exercise. Surprisingly, the patients’ levels of fatigue, depression, and confusion, as measured by the POMS, decreased in response to the exercise.

These data do not confirm the presence of an immunologic process correlating with the exacerbation of fatigue after exercise experienced by patients with CFS. Limitations in the study design and in the sensitivity of the cytokine assays may have affected our results.

 

Source: Lloyd A, Gandevia S, Brockman A, Hales J, Wakefield D. Cytokine production and fatigue in patients with chronic fatigue syndrome and healthy control subjects in response to exercise. Clin Infect Dis. 1994 Jan;18 Suppl 1:S142-6. http://www.ncbi.nlm.nih.gov/pubmed/8148442

 

Chronic fatigue syndrome: immune dysfunction, role of pathogens and toxic agents and neurological and cardial changes

Abstract:

375 patients with chronic fatigue syndrome (CFS) were examined using a standardized questionnaire and subsequent interview on 11 risk factors and 45 symptoms. Additionally immunologic, serologic, toxicologic, neuroradiologic, neurophysiologic and cardiologic investigations were performed.

Immunologic tests showed cellular immunodeficiences particularly in functional regard (pathological lymphocyte stimulation in 50% of the patients, disorders of granulocyte function in 44%). Furthermore variable deviations were found in the lymphocyte subpopulations (CD3, CD4, CD8, CD19, DR, Leu 11 + 19).

In the humoral part tendencies to low IgG-3- and IgG-1-subclass-levels occurred (59% respectively 11% of the patients) also as decreases in complement system (CH50, C3, C4, C1-esterase-inhibitor). In the group of activation markers and cytokines 42% of the investigated patients had circulating immune complexes (CIC), 47% increases of tumor-necrosis-factor (TNF-a) and 21% increases of soluble interleukin-2-receptor (IL-2-R).

The increased occurrence of autoantibodies in the CFS-patients (specially antinuclear anti-bodies [ANA], microsomal thyroid antibodies) suggest, that CFS is associated with or the beginning of manifest autoimmune disease.

Under the pathogens 78% of the patients had a striking serological constellation of Epstein-Barr-Virus (EBV-EA positive, low EBNA-titers), in the HHV-6-Virus 47% showed increased antibody-titers. Tests on further herpes viruses and on Borreliae, Chlamydiae, Candida and Amoebae were positive in 8 to 36% of the examined patients. Furthermore there were found variable deficits of vitamins and trace elements also as hormonal disturbances.

In 26% of the patients there were hints of pollutants (e.g. wood preservatives), in 32 patients blood-levels of pentachlorphenol (PCP) and gamma-hexachlorcyclohexan (γ-HCH, lindan) were measured, which showed vanable increases.

178 (83%) of 225 investigated patients showed disturbances of perfusion in cerebral SPECT imaging, 65 (29%) of 218 patients cerebral punctuate signal changes in cranial magnetic resonance imaging (MRI).

Neurophysiologic measurements (motor evoked potentials, MEP) showed in about 50% of 112 patients prolonged central motor conduction times. 62 patients were additionally investigated by myocardial SPECT-imaging, which was abnormal under exercise in 73%. Our data confirm the concept, that CFS must be considered as a complex psycho-neuro-immunological disorder.

 

Source: Hilgers A, Frank J. Chronic fatigue syndrome: immune dysfunction, role of pathogens and toxic agents and neurological and cardial changes. Wien Med Wochenschr. 1994;144(16):399-406.[Article in German] http://www.scopus.com/record/display.uri?eid=2-s2.0-0027940724&origin=inward&txGid=0

and http://www.ncbi.nlm.nih.gov/pubmed/7856214

 

 

Post-viral fatigue syndrome. A longitudinal assessment in varsity athletes

Abstract:

Maximal oxygen uptake, anaerobic threshold (AT), isometric strength of the elbow flexor and knee extensor muscles, isometric strength endurance exhaustion time (prolonged contraction at 66% of maximal isometric strength), uphill sprinting exhaustion time were longitudinally studied in eight varsity endurance runners with post-viral fatigue syndrome (PVFS).

Prolonged impairment of exercise performance is evident during the course of PVFS. Although maximal oxygen uptake (VO2max) had returned to pre-infection values 13 months after the viral illness (4.160 vs 4.0 L.min-1), AT was still significantly reduced [52 ml.kg-1.min-1, 18.6 km.hr-1, 176 bpm, and 82% of VO2max vs. 49.1 ml.kg-1.min-1 (p < 0.05), 175 bpm (NS), 17.2 km.hr-1 (p < 0.01) and 79% of VO2max (NS)].

Maximal isometric contraction strength of the upper limb remained constant (282 N vs. 274 N), while knee extensor muscles strength decreased significantly (730 N vs. 701 N, p < 0.05). Strength endurance was still significantly reduced by the end of the study (arm average pre-infection: 46.2 sec; end of study: 29.3 sec, p < 0.001; leg average pre-infection: 66.4 sec; end of study: 49.1 sec, p < 0.01). Up hill sprinting time was similarly reduced by the end of the study period (29.3 sec vs. 16.2 sec, p < 0.01).

Both aerobic and anaerobic exercise variables are seriously affected by post-viral fatigue syndrome, and one year may not be sufficient to fully recover.

 

Source: Maffulli N, Testa V, Capasso G. Post-viral fatigue syndrome. A longitudinal assessment in varsity athletes. J Sports Med Phys Fitness. 1993 Dec;33(4):392-9. http://www.ncbi.nlm.nih.gov/pubmed/8035588

 

The grey area of effort syndrome and hyperventilation: from Thomas Lewis to today

Abstract:

Lewis used the diagnosis ‘effort syndrome’ for subjects whose ability to make and sustain effort had been reduced by homeostatic failure. A major element was depletion of the body’s capacity for buffering the acids produced by exercise.

In his view this systems disorder was not to be regarded as a specific organ disease, and losing sight of the metabolic element would foster the invention of fanciful, unphysiological diagnoses. His views were dismissed because normal resting plasma bicarbonate levels were considered by others in that era to exclude serious depletion of the body’s total capacity for buffering the effects of exertion.

Today, effort syndrome is still a useful diagnosis for a condition of exhaustion and failure of performance associated with depletion of the body’s buffering systems. Other elements associated with homeostatic failure are now recognised, principally emotional hyperarousal and hyperventilation. Their physiological interrelationships are described. Effort syndrome is amenable to recovery through rehabilitation, and it may be a mistake to treat chronic fatigue syndrome and unspecific illness without including it in the differential diagnosis.

 

Source: Nixon PG. The grey area of effort syndrome and hyperventilation: from Thomas Lewis to today. J R Coll Physicians Lond. 1993 Oct;27(4):377-83. http://www.ncbi.nlm.nih.gov/pubmed/8289156

 

Exercise performance and fatiguability in patients with chronic fatigue syndrome

Abstract:

To examine the role of delay in recovery of peripheral muscle function following exercise in the fatigue experienced by patients with the chronic fatigue syndrome (CFS) and to examine the influence of effort perception in limiting exercise performance in these patients, a study was carried out on a group of twelve patients with chronic fatigue syndrome and 12 sex and age-matched sedentary control subjects.

Symptom limited incremental cycle exercise tests including measurements of perceived exertion were performed followed by examination of the contractile properties of the quadriceps muscle group for up to 48 hours. Muscle function was assessed by percutaneous electrical stimulation and maximum voluntary contractions.

Muscle function at rest and during recovery was normal in CFS patients as assessed by maximum isometric voluntary contraction, 20:50 Hz tetanic force ratio and maximum relaxation rate. Exercise duration and the relationship between heart rate and work rate during exercise were similar in both groups.

CFS patients had higher perceived exertion scores in relation to heart rate during exercise representing a reduced effort sensation threshold of 3.2 units on an unmodified Borg scale in CFS patients. Patients with chronic fatigue syndrome show normal muscle physiology before and after exercise. Raised perceived exertion scores during exercise suggest that central factors are limiting exercise capacity in these patients.

Comment in: Lactate responses to exercise in chronic fatigue syndrome. [J Neurol Neurosurg Psychiatry. 1994]

 

Source: Gibson H, Carroll N, Clague JE, Edwards RH. Exercise performance and fatiguability in patients with chronic fatigue syndrome. J Neurol Neurosurg Psychiatry. 1993 Sep;56(9):993-8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC489735/ (Full article)