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Query: UMLS:C0015674 (chronic fatigue syndrome)
 2,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxidative metabolism is the major source of energy for muscle activity, and maximal oxygen uptake (VO2max), the product of maximal cardiac output and maximal arteriovenous oxygen difference, indicates individual capacity for oxidative metabolism and performance of exercise by the large muscles. Strength, a function of muscle cross-sectional area, motor-unit recruitment, and neuromuscular coordination, is the ability to develop force in a single, brief, maximal-effort voluntary contraction of rested muscle. Weakness is a diminished ability of rested muscle to exert maximal force. Fatigue is a loss of maximal force-generating capacity that develops during muscular activity, likely originates within muscle itself, and persists until muscle is fully recovered. Individual perception of motor effort can be determined with standardized rating scales. These concepts are discussed in detail, their relevance to the pathophysiology of exercise in chronic fatigue syndrome is analyzed, and a general strategy of exercise evaluation pertinent to chronic fatigue syndrome is presented.
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PMID:Physiologic measurement of exercise and fatigue with special reference to chronic fatigue syndrome. 202 Aug 10

Natural selection results in adaptations. I suggest that unexplained fatigue may be an adaptive response to nasal impairment. For macrosmatic animals, intact olfaction is necessary to detect predators. In such animals, any reflex (e.g., fatigue) triggered by nasal dysfunction that limited exposure would offer great survival advantage. The "fatigued" animal would remain in its protected environment, unexposed to hungry carnivores, while the nose healed. In humans, clinical syndromes associated with unexplained fatigue (chronic fatigue syndrome, tension fatigue syndrome, allergic fatigue, neurasthenia, etc.) are characterized by symptoms that, in part, are nasal in origin. The older medical literature does describe the resolution of fatigue in neurasthenia after nasal treatments. Nasal reflexes in animals do cause significant systemic effects, including an inhibition of muscle action potentials that is, perhaps, analogous to the "heavy-limbed" sensation of those with fatigue. Furthermore, reflexes similar to the one proposed do exist in humans: the diving reflex presumably served our amphibian ancestors well as an oxygen conserving technique with submersion, but serves no known useful function now. Other human nasopharyngeal reflexes with profound cardiovascular and systemic effects are well described but only occasionally studied. The proposed nasal fatigue reflex should be examined as a possible ancient adaptive response to nasal malfunction.
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PMID:Hypothesis: the nasal fatigue reflex. 847 44

The purpose of this study was to determine if patients with the chronic fatigue syndrome have less vagal power during walking and rest periods following walking, in comparison to a group of healthy controls. Eleven patients (ten women and one man) who fulfilled the case definition for chronic fatigue syndrome modified to reduce heterogeneity and eleven healthy, but sedentary, age- and sex-matched controls walked on a treadmill at 2.5 mph four times each for 4 min duration. Between each period of walking, subjects were given a 4-min seated rest period. Vagal power, a Fourier-based measure of cardiac, parasympathetic activity in the frequency range of 0.15 to 1.0 Hz, was computed. In each period of walking and in one period of rest, patients had significantly less vagal power than the control subjects despite there being no significant group-wise differences in mean heart rate, tidal volume, minute volume, respiratory rate, oxygen consumption or total spectrum power. Further, patients had a significant decline in resting vagal power after periods of walking. These results suggest a subtle abnormality in vagal activity to the heart in patients with the chronic fatigue syndrome and may explain, in part, their post-exertional symptom exacerbation.
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PMID:Decreased vagal power during treadmill walking in patients with chronic fatigue syndrome. 898 21

An elite ultra-endurance athlete, who had previously undergone physiological and performance testing, developed chronic fatigue syndrome (CFS). An incremental cycling exercise test conducted while he was suffering from CFS indicated decreases in maximum workload achieved (Wmax; -11.3%), the maximum oxygen uptake (VO2max; -12.5%), and the anaerobic threshold (AT; -14.3%) compared to pre-CFS data. A third test conducted after the athlete had shown indications of significant improvement in his clinical condition revealed further decreases in Wmax (-7.9%), VO2max (-10.2%) and AT (-8.3%). These data, along with submaximal exercise data and muscle biopsy electron microscopic analyses, suggest that the performance decrements were the result of detraining, rather than an impairment of aerobic metabolism due to CFS per se. These data may be indicative of central, possibly neurological, factors influencing fatigue perception in CFS sufferers.
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PMID:The case history of an elite ultra-endurance cyclist who developed chronic fatigue syndrome. 974 1

The purpose of this study was to determine if chronic fatigue syndrome (CFS) is associated with reduced oxygen delivery to muscles. Patients with CFS according to CDC (Center for Disease Control) criteria (n=20) were compared with normal sedentary subjects (n=12). Muscle oxygen delivery was measured as the rate of post-exercise and post-ischaemia oxygen-haem resaturation. Oxygen-haem resaturation was measured in the medial gastrocnemius muscle using continuous-wavelength near-IR spectroscopy. Phosphocreatine resynthesis was measured simultaneously using (31)P magnetic resonance spectroscopy. The time constant of oxygen delivery was significantly reduced in CFS patients after exercise (46.5+/-16 s; mean+/-S.D.) compared with that in controls (29.4+/-6.9 s). The time constant of oxygen delivery was also reduced (20.0+/-12 s) compared with controls (12.0+/-2.8 s) after cuff ischaemia. Oxidative metabolism was also reduced by 20% in CFS patients, and a significant correlation was found between oxidative metabolism and recovery of oxygen delivery. In conclusion, oxygen delivery was reduced in CFS patients compared with that in sedentary controls. This result is consistent with previous studies showing abnormal autonomic control of blood flow. Reduced oxidative delivery in CFS patients could be specifically related to CFS, or could be a non-specific effect of reduced activity levels in these patients. While these results suggest that reduced oxygen delivery could result in reduced oxidative metabolism and muscle fatigue, further studies will be needed to address this issue.
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PMID:Impaired oxygen delivery to muscle in chronic fatigue syndrome. 1054 13

This study examined the effects of exhaustive exercise on cognitive functioning among 21 monozygotic twin pairs discordant for chronic fatigue syndrome (CFS). The co-twin control design adjusts for genetic and family environmental factors not generally accounted for in more traditional research designs of neuropsychological function. Participants pedaled a cycle ergometer to exhaustion; maximum oxygen output capacity (VO2max) as well as perceived exertion were recorded. Neuropsychological tests of brief attention and concentration, speed of visual motor information processing, verbal learning and recognition memory, and word and category fluency were administered with alternate forms to participants pre- and postexercise. The preexercise neuropsychological test performance of CFS twins tended to be slightly below that of the healthy twin controls on all measures. However, twins with CFS did not demonstrate differential decrements in neuropsychological functioning after exercise relative to their healthy co-twins. Because exercise does not appear to diminish cognitive function, rehabilitative treatment approaches incorporating exercise are not contraindicated in CFS.
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PMID:Cognitive compromise following exercise in monozygotic twins discordant for chronic fatigue syndrome: fact or artifact? 1138 21

A 68-year-old female referred for excessive daytime sleepiness, strong morning headaches, snoring and suspected chronic fatigue syndrome. The polyMESAM examination was performed with following results: Respiratory Disturbances Index--RDI (average number of apnoeas and hypopnoeas in one hour of registration) 26, Oxygen Desaturation Index--ODI (average number of oxygen haemoglobin saturation drops in one hour) 51, basal oxygen haemoglobin saturation 90% and average oxygen haemoglobin saturation minimas 82%. Her condition was rated as grave OSAS. CPAP therapy was, however, impeded by anxiety state caused by claustrophobia. Analysis of lateral cephalogram proved significant constriction of the retrolingual posterior airway space to 6 mm (the bottom standard limit for women is 12 mm), with a relatively good position of the hyoid bone. The genioglossus advancement surgery was therefore performed on the patient as the only causational therapy. Then the patient referred improvement of sleepiness, snoring, fatigue and morning headache. PolyMESAM recorded two months after the surgery showed a strong improvement of OSAS: RDI 11, ODI 14, basal oxygen haemoglobin saturation 93% and average oxygen haemoglobin saturation minimas 89%.
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PMID:[Genioglossal advancement in the surgical treatment of obstructive sleep apnea syndrome in adults]. 1170 82

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.
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PMID:Blood volume and its relation to peak O(2) consumption and physical activity in patients with chronic fatigue. 1174 48

Biological clock and magnesium status are linked. Central magnesium regulation may be hypothetized. Balanced magnesium status is requested to obtain efficiency of suprachiasmatic nuclei and of pineal gland. Conventional bright light therapy appears as a speedy and efficient antidepressant medication useful for the treatment of various types of depression, and of non migrainous headaches also. Although decrease in melatonin production seems accessory, increases of serotonergy and perhaps of Reactive Oxygen Species constitute the main mechanisms of action. Chromatotherapy emphazizes the effects of short exposure to specific colors. Although the increased production of melatonin constitutes the best marker of darkness, it is only an accessory mechanism of its action. The psycholeptic sedative effects of darkness, like those of magnesium, rely on direct membraneous and oxidant actions, neural mediated effects (i.e. stimulation of inhibitory neuromodulators such as GABA and taurine), and on antagonism of neuroactive gases (CO and NO). Darkness therapyper se, partial substitutive therapy with melatonin and with their mimicking agents (Mg, L-Tryptophan,Taurine) apply to all the chronopathological forms of magnesium depletion with decreased production of melatonin: sleep disorders, migraine, chronic fatigue syndrome, fibromyalgia, some forms of asthma and of sudden infant death syndrome. Further research should assess the importance of the chronopathological forms of magnesium depletion in the physiopathology of these disorders.
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PMID:Biorhythms and possible central regulation of magnesium status, phototherapy, darkness therapy and chronopathological forms of magnesium depletion. 1203 Apr 24

The purpose of this study was to determine if chronic fatigue syndrome (CFS) is associated with reduced blood flow and oxidative delivery to skeletal muscle. Patients with CFS according to CDC (Center for Disease Control) criteria ( n =19) were compared with normal sedentary subjects ( n =11). Muscle blood flow was measured with Doppler ultrasound after cuff ischaemia and exercise. Muscle oxygen delivery was measured as the rate of post-exercise and post-ischaemic oxygen-haem resaturation. Oxygen-haem resaturation was measured in the medial gastrocnemius muscle using continuous wavelength near-IR spectroscopy. Muscle metabolism was measured using (31)P magnetic resonance spectroscopy. CFS patients and controls were not different in the peak blood flow after cuff ischaemia, the rate of recovery of phosphocreatine after submaximal exercise, and the rate of recovery of oxygen saturation after cuff ischaemia. In conclusion, CFS patients showed no deficit in blood flow or oxidative metabolism. This suggests that CFS symptoms do not require abnormal peripheral function.
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PMID:Blood flow and muscle metabolism in chronic fatigue syndrome. 1258 4


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