Physical fatigue

Figure 19.17 The biochemistiy and physiology responsible for penile erection. Sexual activity itself begins with a state of arousal that leads to erection. Arousal results in part from stimulation of the sense organs. The hypothalamus coordinates the sensations and activates the autonomic nervous system. Sensory nerves from the skin of the penis and other erogenous zones stimulate the parasympathetic system. This activates nitric oxide synthase and the resultant nitric oxide, via cyclic GMP, causes vasodilation of the arterioles. This increases blood flow through the corpora cavernosa which then expands producing an erection. Pheromones secreted by the female can stimulate the odour detecting system in the nasal cavity of the male (Chapter 12 and see above). Stress, however, activates the sympathetic system releases cyclic AMP which can result in vasoconstriction of the arterioles. Other factors that can interfere with an erection are physical fatigue and alcohol.

Many over-the-counter preparations are aimed at relieving fatigue through CNS stimulation. Such compounds are often referred to as wake-up tablets, but these methylxanthine-containing products do little to offset physical fatigue, so they place individuals using them at risk for accidental injuries. 

The seeds of the Brazilian plant Paullinia cupana (Sapindaceae) are used to make a stimulant drink. Crushed seeds are mixed with water to a paste, which is then sun dried. Portions of this are then boiled with hot water to provide a refreshing drink. The principal constituent, previously called guaranine, has been shown to be identical to caffeine, and the seeds may contain 3-5%. Small amounts of theophylline (0-0.25%) and theobromine (0.02-0.06%) are also present. Guarana is widely available as tablets and capsules, or as extracts, in health food shops where it is promoted to relieve mental and physical fatigue. Labels on such products frequently show the active constituent to be guaranine, but may not indicate that this is actually caffeine. 

Somerville W. The effect of benzedrine on mental or physical fatigue in soldiers. Can Med Assoc J 1946 55 470-476. 

Burn patients consume many resources and have long lengths of stay. After the response to the disaster is over, these patients can remain hospitalized for months. The average length of stay for a patient with 50% TBSA burns is 50 days. Burn center staff may become exhausted, operating at or above capacity for this period of time. It is recommended that staff work regular 8-hour shifts if possible to prevent emotional and physical fatigue. 

Fatigue is one of the most commonly reported adverse effects of beta-adrenoceptor antagonists, with reported occurrence rates of up to 20% or more, particularly in those who exert themselves. It has to be viewed alongside the ability to produce fatigue and lethargy by a possible effect on the nervous system. The precise cause of physical fatigue is not known, but hjrpotheses include impaired muscle blood supply, effects on intermediary metabohsm, and a direct effect on muscle contractihty (4). 

They seemed to make an association between goiter and physical fatigue. 

The least severe category would be characterized by deterioration in memory function and abihty to concentrate, physical fatigue, and irritabihty, while the second level would involve sustained mood and personality changes, as well as further deterioration of intellectual functions, including learning capacity. At least some of the effects of chronic exposure appear to persist well beyond the termination of the exposure, and may be permanent. 

Cortisone is released from the adrenal cortex at times of stress. It delays physical fatigue by increasing the ability of muscles to contract and has a euphoric effect on the brain which may give added confidence at a stressful time. 

OOS, or occupational overuse syndrome, is a condition of generalized or particular mental or physical fatigue, which may be accompanied by physical pain, and resnlts from overuse of particular parts of the body to perform work tasks. 

Rig workers often need to reach a work station in the derrick several times during their shift. It is often less a hazard to have the worker ride the hoisting equipment than have a physically fatigued employee make the climb. 

From the sample studied, 87.2% of workers say that they feel psychologically tired namely after the afternoon shift (75.6%). As for physical fatigue mentioned by respondents (95.3%), they feel tired when a shift is finishing being it mainly the afternoon shift the most tiring (82.6%). 

Queries intend to evaluate the individual perception of environmental comfort and physical fatigue. A higher number of subjects reveal discomfort when exposed to cold environment. In the query Analysis of Thermal Environment at Workstations, 4 in 13 subjects answered that they feel Very cold and 8 in 13 subjects Slightly Cold . 

Regulatory Status. GRAS both cola nut and kola nut are listed ( 182.20). Subject of a German therapeutic monograph as an analeptic for use in mental and physical fatigue. ... 

Nagle FJ, Balke B, Ganslen RV, Davis AW. The mitigation of physical fatigue with Spartase. US Civil Aeromed Res Inst Rep Civ Aeromed Inst US 1963 Jul 94 1—10. 

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