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Query: UMLS:C0015672 (fatigue)
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Rhodiola rosea L., or 'golden root', is a popular plant in traditional medicine in Eastern Europe and Asia, with a reputation for improving depression, enhancing work performance, eliminating fatigue and treating symptoms of asthenia subsequent to intense physical and psychological stress. Due to these therapeutic properties, R. rosea is considered to be one of the most active adaptogenic drugs. To confirm and extend results obtained in the few preclinical and clinical studies available in English language journals, the purpose of the present study was to re-investigate the effects produced by a single oral administration of an R. rosea hydroalcohol extract (containing 3% rosavin and 1% salidroside) on the central nervous system in mice. The extract was tested on antidepressant, adaptogenic, anxiolytic, nociceptive and locomotor activities at doses of 10, 15 and 20 mg/kg, using predictive behavioural tests and animal models. The results show that this R. rosea extract significantly, but not dose-dependently, induced antidepressant-like, adaptogenic, anxiolytic-like and stimulating effects in mice. This study thus provides evidence of the efficacy of R. rosea extracts after a single administration, and confirms many preclinical and clinical studies indicating the adaptogenic and stimulating effects of such R. rosea extracts. Moreover, antidepressant-like and anxiolytic-like activities of R. rosea were shown in mice for the first time.
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PMID:Adaptogenic and central nervous system effects of single doses of 3% rosavin and 1% salidroside Rhodiola rosea L. extract in mice. 1707 30

Repetitive work in occupational settings often requires a combination of mental and physical demands, but few studies were conducted concerning the relationship between attention and repetitive work. In attentive and cognitive tasks, it is common to observe effort and fatigue without the presence of those neuromuscular modifications that would justify the use of these terms. Therefore, we can talk about mental fatigue in those cases in which it is observed the exhaustion of the necessary resources for the execution of a job that doesn't demand the employment of neuromuscular apparatus. Scientific literature about this argument consists of experimental studies which aim to estimate at what extent attentive demands exspecially cognitive demands can interact with physical ones which are peculiarities of repetitive tasks. Work characterized by the maintenance of high levels of performance for a long time, produce cognitive effort with high level of vigilance, selective attention, decisional ability, automated control mechanisms, such as "eye-hand", and may contribute to the fatigue. Indeed, fatigue plays a important role in a working context since, it may interfere with the work itself by reducing the worker's efficiency and performance and if excessive and extended, it may alter the subject's psycho-physical condition and induce different pathologies. Repetitive work can contribute to the increasing of muscular fatigue by inducing mental fatigue: for example tasks which require high vigilance but low neuromuscular work, may induce a sense of effort and fatigue and cognitive factors and mental stress may cause muscular fatigue. Several intrinsic job factors, including repetitive works, may act as stressors and they can cause mental and physical symptoms such as anxiety, depression and somatic diseases. The European Community has often emphasized the pathogenic value of stress and fatigue with their high social and individual costs. For this purpose, it is opportune to consider the norm UNI EN ISO 10075, which points out the necessity to consider the human component, in term of mental load which implies not only the cognitive component but also the whole psychical sphere of the subject. Training intended like a sort of learning of specific modalities, supplies workers with the necessary instruments for a correct and more aware management of the peculiarities of working activity, contributing to the reduction of fatigue and stress deriving from the job.
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PMID:[Attention, repetitive works, fatigue and stress]. 1708 57

The physical load increase during training can lead to the development of clinical patterns of intolerance differing according to their severity, prognosis and reversibility. However, they always include fatigue as a key symptom. The aim of this paper is to review recent data on fatigue states in sportsmen, their clinical presentation and diagnostic orientations. A continuum exists, from acute fatigue states after one or several highly-intensive training sessions, to overreaching, associated to performances alteration which can be easily reversed, and to overtraining, representing a severe clinical pattern which can hardly be reversed. Overreaching and overtraining are characterized by a persisting fatigue state, associated to performances alteration and mood disorders. In an athlete with unexplained alteration of performances associated to physical fatigue, the medical interrogation is critical, in order to check the durable character of sportive performances alteration, to describe the fatigue and identify risk factors of occurrence of overtraining (training program intensity, mental stress, diet factors, hypoxic training, etc.). The use of a validated and adapted questionnaire as the one proposed by the French Society of Sports Medicine is valuable. In majority, in athletes and those doing sports regularly, the cardiological alert signs are rare, and the clinical examination by a specialist is poorly contributive, except for eliminating an organic cause of fatigue.
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PMID:[Cardiological aspects of fatigue states in athletes]. 1718 Oct 37

In 2003 were promulgated the texts regulating rest and safety, in the USA (approved by the ACGME) and in France (January 9th, 2001 and September 14th, 2001). The institution of the "rest for safety", an eleven hours duration interruption of activity, immediately after a night-call, can be viewed as a progress in the search for safety. Several studies showed a link between excessive work hours and occurrence of medical incidents related to tiredness. However published data do not show a link between tiredness and patients endangering. The tiredness resulting from sleep deprivation and disturbances in circadian rhythms is a cumulative phenomenon erased by a period of rest. In spite of a large individual variability, tiredness increases anxiety scores, irritability, depression and it deteriorates cognitive performances. The concept of "prophylactic" rest considers that a subject cannot start, rested, a work if he did not sleep at least 5 hours the previous night, or 12 hours during the previous 48 hours. The second important aspect of the rest for safety is the long-term prevention of potential pathologies in medical staff, in particular burnout syndrome. In our profession, night calls are considered most stressful; the psychological stress related to anticipation and night context causes measurable cardiovascular disturbances in anesthesiologists. Shift-work sleep disorders may induce gastric ulcers, heart attacks, metabolic syndrome, depression and accidents related to somnolence. Long duration work-hours, accompanied by sleep deprivation, may double the risk of car accidents in junior physicians, in whom vigilance levels can compare with those of patients concerned by narcolepsy or with the cognitive disturbances induced by alcohol intoxication. Reduced work-hours improve vigilance and divide by three the rate of serious medical errors. True opportunities of sleep and control of sleep duration at the individual level could be suggested. The idea that taking the necessary rest would be synonymous with a decrease of efficiency in patient care is not demonstrated, but the danger of a poorer information transmission should be handed with an optimization of our manpower and organization. Aging is accompanied by a progressive disorganization of sleep. The foreseeable shortage of manpower, synonymous with aging of the medical actors and increased vulnerability to tiredness, is a posteriori the justification of the institution of the rest for safety.
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PMID:[Rest for safety: which stakes?]. 1748 45

Inappropriate sinus tachycardia (IST) is an uncommon form of arrhythmia which is characterized by an exaggerated increase in heart rate that is out of proportion to normal physiologic demands. Usually, IST is triggered by orthostasis, minimal exertion, and psychological stress. The etiology of IST remains ill-defined. However, proposed mechanisms include: enhanced sinus node automaticity, alterations in autonomic function associated with increased sympathetic activity or reduced parasympathetic activity, and impaired baroreflex control. Recently, increased levels of autoantibodies to beta-adrenergic receptors have been observed in patients with IST. The clinical presentation of IST is highly varied and ranges from short episodes of palpitations associated with dyspnea, atypical precordial pain, cephalalgia, fatigue, and occasional syncope and presyncope to incapacitating incessant tachycardia. In general, IST is a diagnosis of exclusion. It is important that other causes of sinus tachycardia are excluded before making a diagnosis. Evaluation of autonomic function is essential for a diagnosis of IST. Treatment of IST is based on autonomic function findings and involves multidisciplinary management, including cardiac rehabilitation. Control and restitution of normal autonomic function is essential. The prognosis is benign though regular follow-up is required to optimize therapy.
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PMID:[Inappropriate sinus tachycardia: an update]. 1809 89

Women are four to eight times more likely to be affected by fibromyalgia syndrome (FMS). A lack of cortisol, potentially due to an adrenocortical deficit is postulated in FMS. The cause of such adrenal insufficiency is unknown. It could be assumed that stress exposure during critical periods contributes to vulnerability for FMS. These critical periods might include prenatal periods in which adversities may lead to an impaired development of the adrenal cortex, especially in females. More than 50% of FMS patients report major life events before the onset of the disease. Possibly due to adrenal insufficiency they may not be able to dampen their stress response by secreting sufficient glucocorticoids. Thus, stress mediators, such as catecholamines and pro-inflammatory cytokines, may be disinhibited and affect brain function. This might result in an enhanced responsiveness to external and internal pain- and fatigue-eliciting stimuli. In a study with female FMS patients (N= 93) those patients with a shorter gestational length (<38 weeks) showed a lower cortisol awakening response (CAR) than FMS subjects with a gestational length >38 weeks (F((3,31))= 2.94, P= 0.038). Additionally, more than 70% reported severe psychological stress alone or in combination with other factors at disease onset.
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PMID:Sex-specific prenatal programming: a risk for fibromyalgia? 1912 Jan 40

Chronic low blood pressure is typically accompanied by symptoms such as fatigue, reduced drive, dizziness, headaches and cold limbs. Reduced cognitive performance, diminished cerebral blood flow and autonomic dysregulation have been furthermore documented in this condition. The present contribution reports two studies exploring systemic hemodynamics in chronic hypotension and their modification through vasopressor application. In study I, effects of the alpha-sympathomimetic midodrine were examined in 54 hypotensive individuals using a placebo-controlled double-blind design. Hemodynamic parameters were assessed at rest and during mental stress. They were derived from continuous blood pressure recordings using Modelflow analysis. The drug led to marked increases in blood pressure, total peripheral resistance and stroke volume. However, due to strong heart rate deceleration, cardiac output remained virtually unchanged. In study II, 40 hypotensive and 40 normotensive control persons were compared with respect to hemodynamics. While groups did not differ in total peripheral resistance, hypotensives exhibited markedly diminished stroke volume and heart rate, resulting in a reduction in cardiac output of 25% at rest and of 33% during mental stress. The data provide relevant knowledge about the hemodynamic mediation of chronic hypotension. In contrast to elevated blood pressure, which is mainly determined by increased peripheral resistance, reduced cardiac output may be the cardinal hemodynamic aberration in chronic hypotension. Midodrine proved to be effective in elevating blood pressure. However, given the cardiac origin of chronic hypotension and the lack of drug effect on cardiac output, alpha-sympathomimetic treatment may be suboptimal.
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PMID:Hemodynamic determinants of chronic hypotension and their modification through vasopressor application. 1934 May 50

Information on cerebral oxygenation during prolonged driving in healthy humans may help to explain the cause and development of central fatigue and its effects on cortex activities. The objective of this study is to investigate the time course of cerebral oxygenation during a prolonged driving task. Forty healthy male subjects were randomly divided into two groups: task group (Task) and control group (CNL). All subjects were required to rest well prior to the experiment. For the task group, subjects were required to perform the simulated driving task for 3 h. Cerebral oxygenation signal was monitored from the left frontal lobe using near infrared spectroscopy throughout the entire experiment. Significant increases in the concentrations of HbO(2) (DeltaCHbO(2)) and HbT (DeltaCHbT) were recorded at the start of driving task compared with the resting value (p < 0.01). The cerebral oxygen saturation in the Task group was found to be significantly lower following three hours of driving compared with that in the CNL (F = 16.95, p < 0.001). In addition, a significant difference in selective reaction time was observed between the Task group and CNL during the post-task period (p = 0.023). The results demonstrated that the cerebral oxygenation is closely related to the mental stress. The decrease in the cerebral oxygen saturation may indicate reduced cerebral oxygen delivery, and this may be an important factor affecting central fatigue development during prolonged driving.
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PMID:Assessment of cerebral oxygenation during prolonged simulated driving using near infrared spectroscopy: its implications for fatigue development. 1957 70

Chronic low blood pressure is typically accompanied with symptoms such as fatigue, reduced drive, dizziness, headaches and cold limbs. Alterations in autonomic cardiovascular regulation are assumed to be involved in the etiology of this condition, that is, increased baroreflex sensitivity (BRS) as well as reduced sympathetic and augmented parasympathetic influences on cardiovascular regulation. In this study, the acute effects of the blood pressure-enhancing alpha-adrenergic agonist, midodrine, on autonomic cardiovascular control were investigated in 50 hypotensive persons (mean blood pressure 96/61 mm Hg) based on a placebo-controlled double blind design. BRS was determined using sequence analysis. Spectral analysis of heart rate variability was carried out to quantify sympathetic and parasympathetic cardiac control. Parameters were obtained at rest and during mental stress. Drug application led to marked increases in blood pressure, BRS and respiratory sinus arrhythmia (RSA), whereas heart rate and power in the low frequency (LF) band of the heart rate variability spectrum decreased. The augmentation of RSA and reduction of LF power indicate a shift of the sympathovagal balance toward increased parasympathetic and reduced sympathetic influences on heart rate. Like the increase in BRS, these modulations represent a counter-regulatory autonomic response to the blood pressure elevation, which is initiated to return blood pressure to the initial value or to an individual set point. The finding challenges the use of alpha-sympathomimetics in the treatment of chronic hypotension as they may not reduce but may instead exacerbate the autonomic dysbalance related to this condition.
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PMID:Modulations of autonomic cardiovascular control following acute alpha-adrenergic treatment in chronic hypotension. 1979 98

The present article presents epidemiological, and comparative evidence supporting the hypothesis that rheumatoid arthritis (RA) may represent a thrifty adaptation selected to compel animals to minimize voluntary energy expenditure. The autoimmune, pathophysiological manifestations underlying RA are framed here as constituting an evolved, protective mechanism that would have influenced animals to avoid exertion and maintain a sedentary lifestyle in order to minimize metabolic output and ultimately escape starvation. Arthritic pain is characterized here as a defensive, innate signal much like fatigue, fever, nausea and reflexive pain, and like these, is seen on a continuum varying between imperceptible encumbrance and debilitating disability. The epigenetic relationship between acute psychological stress and flare-up of arthritic symptoms is examined and taken to suggest that arthritis may be a predictive, adaptive response to severe stress allowing reductions in metabolism to follow adverse conditions or nutritional scarcity. The close associations between rheumatoid arthritis and the metabolic syndrome are also explored along with potential ties to the "thrifty genotype" and "thrifty phenotype" phenomena. This hypothesis is examined in the contexts of evolutionary medicine, phenotypic plasticity, the stress response and the bioenergetics of thrift. A brief and exploratory review of pertinent evidence suggests that RA, its subclinical manifestations, and even other forms of arthropathy may possibly represent adaptations that promoted metabolic thrift during our evolutionary past.
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PMID:Does rheumatoid arthritis represent an adaptive, thrifty condition? 1971 39


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