Tag: inactivity

Chronic unexplained fatigue

Abstract:

Fatigue is a common symptom in the community and the commonest associations are with stress or mood disturbance. One in a hundred people complain of unexplained and prolonged fatigue, with half that number meeting the strictest criteria for the chronic fatigue syndrome (CFS). Discrete fatigue syndromes have been described, particularly after Epstein Barr virus infection. The majority of patients with CFS have a syndrome similar to the ICD-10 definition of neurasthenia. Mood and somatoform disorders are common comorbid or differential diagnoses. The prognosis is poor, particularly in patients attending hospitals and those with comorbid psychiatric disorders. The aetiology of both CFS and chronic unexplained fatigue are essentially unknown, perhaps reflecting the heterogenenous natures of both the symptom and syndrome. There is reasonable evidence to suggest that particular infections may trigger both prolonged fatigue and CFS. Maintaining factors are different from triggering factors and include mood and sleep disorders, illness beliefs and behaviours, and possibly inactivity. Treatments aimed at reversing these maintaining factors show promise.

 

Source: White PD. Chronic unexplained fatigue. Acta Neuropsychiatr. 1999 Dec;11(4):130-3. doi: 10.1017/S0924270800035870. http://www.ncbi.nlm.nih.gov/pubmed/26976541

 

Muscle fibre characteristics and lactate responses to exercise in chronic fatigue syndrome

Abstract:

OBJECTIVES: To examine the proportions of type 1 and type 2 muscle fibres and the degree of muscle fibre atrophy and hypertrophy in patients with chronic fatigue syndrome in relation to lactate responses to exercise, and to determine to what extent any abnormalities found might be due to inactivity.

METHODS: Quadriceps needle muscle biopsies were obtained from 105 patients with chronic fatigue syndrome and the proportions of type 1 and 2 fibres and fibre atrophy and hypertrophy factors were determined from histochemical preparations, using a semiautomated image analysis system. Forty one randomly selected biopsies were also examined by electron microscopy. Lactate responses to exercise were measured in the subanaerobic threshold exercise test (SATET).

RESULTS: Inactivity would be expected to result in a shift to type 2 fibre predominance and fibre atrophy, but type 1 predominance (23%) was more common than type 2 predominance (3%), and fibre atrophy was found in only 10.4% of cases. Patients with increased lactate responses to exercise did have significantly fewer type 1 muscle fibres (p<0.043 males, p<0.0003 females), but there was no evidence that this group was less active than the patients with normal lactate responses. No significant ultrastructural abnormalities were found.

CONCLUSION: Muscle histometry in patients with chronic fatigue syndrome generally did not show the changes expected as a result of inactivity. However, patients with abnormal lactate responses to exercise had a significantly lower proportion of mitochondria rich type 1 muscle fibres.

 

Source: Lane RJ, Barrett MC, Woodrow D, Moss J, Fletcher R, Archard LC. Muscle fibre characteristics and lactate responses to exercise in chronic fatigue syndrome. J Neurol Neurosurg Psychiatry. 1998 Mar;64(3):362-7. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2169994/ (Full article)