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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study examined the effect of a high-carbohydrate diet on the performance of dribbling and shooting skills of recreational soccer players. Six male midfield soccer players first completed 60 minutes of intermittent treadmill exercise, followed either by a mixed or a high-carbohydrate diet for 48 hours. A modified Zelenka Functional Performance Test was then administered, followed by the intermittent treadmill exercise and another skills test. Subjects then repeated the protocol two weeks later under the alternative dietary regime. Blood samples were obtained pre exercise and after each procedure for Hematocrit and concentrations of hemoglobin, plasma glucose and lactate. Heart rate was recorded during and after each procedure. Repeated measures MANOVA revealed (1) the skill performance was not impaired by the intermittent treadmill exercise (p > 0.05); (2) the high-carbohydrate diet did not increase the ability of players to shoot or dribble (p > 0.05); (3) a significant increase in heart rate during the post treadmill exercise skill test compared with that during the pre treadmill exercise test (p < 0.05); (4) a significant order by time effect for hematocrit (p < 0.05); (5) no significant differences in plasma glucose, plasma lactate or hemoglobin concentrations between tests (p > 0.05); and (6) a significant decrease in body mass from pre to post dietary regime within both conditions (p < 0.05). It is speculated that either (1) muscle glycogen depletion may not impair the ability of the player to execute game skills; (2) an alternative fatigue mechanism such as dehydration or increased lactate production may be causative factors in the reduction in skill performance; or (3) the treadmill protocol employed failed to induce a degree of glycogen depletion or fatigue large enough to cause a significant fall in skill performance.
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PMID:The effect of a high-carbohydrate diet on the skill performance of midfield soccer players after intermittent treadmill exercise. 992 28

Pseudo-hypoaldosteronism (PHA) is due to mineralocorticoid resistance and manifests as hyponatremia and hyperkalemia with increased plasma aldosterone levels. It may be familial or secondary to abnormal renal sodium handling. We report the case of a 54-year-old woman with multifocal cancer of the colon, who developed PHA after subtotal colectomy, ileal resection and jejunostomy. She was treated with 6 g of salt daily to prevent dehydration, which she stopped herself because of reduced fecal losses. One month later she was admitted with signs of acute adrenal failure, i.e. fatigue, severe nausea, blood pressure of 80/60 mmHg, extracellular dehydration, hyponatremia (118 mmol/l); hyperkalemia (7.6 mmol/l), increased blood urea nitrogen (BUN) (200 mg/dl) and creatininemia (2.5 mg/dl), and decreased plasma bicarbonates level (HCO3-: 16 mmol/l; N: 27-30). However, the plasma cortisol was high (66 microg/100 ml at 10:00 h; N: 8-15) and the ACTH was normal (13 pg/ml, N: 10-60); there was a marked increase in plasma renin activity (>37 ng/ml/h; N supine <3), active renin (869 pg/ml; N supine: 1.120), aldosterone (>2000 pg/ml; N supine <150) and plasma AVP (20 pmol/l; N: 0.5-2.5). The plasma ANH level was 38 pmol/l (N supine: 5-25). A urinary steroidogram resulted in highly elevated tetrahydrocortisol (THF: 13.3 mg/24h; N: 1.4+/-0.8) with no increase in tetrahydrocortisone (THE: 3.16 mg/24h; N: 2.7+/-2.0) excretion, and with low THE/THF (0.24; N: 1.87+/-0.36) and alpha THF/THF (0.35; N: 0.92+/-0.42) ratios. The number of mineralocorticoid receptors in mononuclear leukocytes was in the lower normal range for age, while the number of glucocorticoid receptors was reduced. Small-bowel resection in ileostomized patients causes excessive fecal sodium losses and results in chronic sodium depletion with contraction of the plasma volume and severe secondary hyperaldosteronism. Nevertheless, this hyperaldosteronism may be associated with hyponatremia and hyperkalemia suggesting PHA related to the major importance of the colon for the absorption of sodium. In conclusion, this case report emphasizes 1) the possibility of a syndrome of acquired PHA with severe hyperkalemia after resection of the ileum and colon responding to oral salt supplementation; 2) the major increase in AVP and the small increase in ANH; 3) the strong increase in urinary THF with low THE/THF and alpha THF/THF ratios; 4) the normal number of lymphocytic mineralocorticoid receptors outside the acute episode.
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PMID:Transient pseudo-hypoaldosteronism following resection of the ileum: normal level of lymphocytic aldosterone receptors outside the acute phase. 1019 79

The cause of fatigue during prolonged exercise in the heat has not been clearly established, but performance appears to be limited by thermoregulatory and fluid balance factors. Both dehydration and hyperthermia separately impair performance. Prior acclimation reduces the impact of heat, and ingestion of fluids also improves performance. Ingested fluids should contain carbohydrate and some electrolytes, primarily sodium, but many factors will dictate the choice of fluids. These include the relative need for carbohydrate to supplement endogenous stores, the need for fluid replacement, the limitations on replacement imposed by the nature of the event, and the athlete's own requirements and preferences.
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PMID:Exercise in the heat: limitations to performance and the impact of fluid replacement strategies. Introduction to the symposium. 1019 40

An 81-year-old woman developed pilsicainide intoxication associated with dehydration. The patient had been taking pilsicainide (100 mg/day) for 1 year because of paroxysmal atrial fibrillation. Her renal function was within normal limits. One week before admission, she was suffering from pneumonia, and had appetite loss, fever, and severe fatigue. Physical examination revealed dehydration. The electrocardiogram (ECG) on admission showed atrioventricular dissociation, idioventricular rhythm with marked QRS widening and QTc prolongation. The plasma concentration of pilsicainide on admission was markedly elevated at 6.2 microg/ml, approximately 6 times the therapeutic range (0.25-1.0 microg/ml). Continuous saline infusion was initiated for the treatment of dehydration,which progressively improved. As a result, sinus rhythm was recovered 2 h after admission, and the QRS and JT intervals gradually normalized. This is an interesting case because the proarrhythmia of pilsicainide was induced by dehydration.
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PMID:Pilsicainide intoxication in a patient with dehydration. 1020 25

1. The present study examined whether reductions in muscle blood flow with exercise-induced dehydration would reduce substrate delivery and metabolite and heat removal to and from active skeletal muscles during prolonged exercise in the heat. A second aim was to examine the effects of dehydration on fuel utilisation across the exercising leg and identify factors related to fatigue. 2. Seven cyclists performed two cycle ergometer exercise trials in the heat (35 C; 61 +/- 2 % of maximal oxygen consumption rate, VO2,max), separated by 1 week. During the first trial (dehydration, DE), they cycled until volitional exhaustion (135 +/- 4 min, mean +/- s.e.m.), while developing progressive DE and hyperthermia (3.9 +/- 0.3 % body weight loss and 39.7 +/- 0.2 C oesophageal temperature, Toes). On the second trial (control), they cycled for the same period of time maintaining euhydration by ingesting fluids and stabilising Toes at 38.2 +/- 0.1 degrees C. 3. After 20 min of exercise in both trials, leg blood flow (LBF) and leg exchange of lactate, glucose, free fatty acids (FFA) and glycerol were similar. During the 20 to 135 +/- 4 min period of exercise, LBF declined significantly in DE but tended to increase in control. Therefore, after 120 and 135 +/- 4 min of DE, LBF was 0.6 +/- 0.2 and 1.0 +/- 0.3 l min-1 lower (P < 0.05), respectively, compared with control. 4. The lower LBF after 2 h in DE did not alter glucose or FFA delivery compared with control. However, DE resulted in lower (P < 0.05) net FFA uptake and higher (P < 0.05) muscle glycogen utilisation (45 %), muscle lactate accumulation (4.6-fold) and net lactate release (52 %), without altering net glycerol release or net glucose uptake. 5. In both trials, the mean convective heat transfer from the exercising legs to the body core ranged from 6.3 +/- 1.7 to 7.2 +/- 1.3 kJ min-1, thereby accounting for 35-40 % of the estimated rate of heat production ( approximately 18 kJ min-1). 6. At exhaustion in DE, blood lactate values were low whereas blood glucose and muscle glycogen levels were still high. Exhaustion coincided with high body temperature ( approximately 40 C). 7. In conclusion, the present results demonstrate that reductions in exercising muscle blood flow with dehydration do not impair either the delivery of glucose and FFA or the removal of lactate during moderately intense prolonged exercise in the heat. However, dehydration during exercise in the heat elevates carbohydrate oxidation and lactate production. A major finding is that more than one-half of the metabolic heat liberated in the contracting leg muscles is dissipated directly to the surrounding environment. The present results indicate that hyperthermia, rather than altered metabolism, is the main factor underlying the early fatigue with dehydration during prolonged exercise in the heat.
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PMID:Metabolic and thermodynamic responses to dehydration-induced reductions in muscle blood flow in exercising humans. 1052 24

Nine trailer loads of horses (n = 306) transported to slaughter facilities with distances ranging 596 to 2,496 km were studied to characterize the type of horses used in commercial markets and the physiological responses and number of injuries due to transportation under summer environmental conditions. Slaughter horse candidates were middle-aged (11.4+/-.4 yr), possessed moderately fleshy body condition, weighed 432+/-3.3 kg, and were of Quarter Horse or Thoroughbred breeding. The mean weight loss during commercial transport was 4%. The percentage of injured horses was greater (P < .05) for two-tiered "pot-belly" (29.2%) compared with straight-deck (8.0%) trailers; however, the stress indicators of cortisol and neutrophil:lymphocyte ratio and rectal temperature showed greater (P < .05) responses following transport in straight-deck trailers. As trip duration increased from 5 h 45 min to 30 h, muscle fatigue (lactate concentration) and dehydration (hematocrit and total protein concentration) were the major physiological considerations, especially in durations over 27 h. The percentage of horses injured was less (P < .05) in trailers with 1.14 to 1.31 m2 of floor area per horse than in trailers with 1.40 to 1.54 m2 of floor area per horse. However, most physiological responses (white blood cell count, total protein concentration, and neutrophil:lymphocyte ratio) to transportation were less (P < .05) in horses provided with the greater floor area.
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PMID:Responses of horses to trailer design, duration, and floor area during commercial transportation to slaughter. 1056 60

Performance in endurance events is typically evaluated by the power or velocity that can be maintained for durations of 30 min. to four hours. The two main by-products of intense and prolonged oxidative metabolism that can limit performance are the accumulation of hydrogen ion (i.e. lactic acidosis) and heat (i.e. hyperthermia). A model for endurance performance is presented that revolves around identification of the lactate threshold velocity which is presented as a function of numerous morphological components as well as gross mechanical efficiency. When cycling at 80 RPM, gross mechanical efficiency is positively related to Type I muscle fiber composition, which has great potential to improve endurance performance. Endurance performance can also be influenced by altering the availability of oxygen and blood glucose during exercise. The latter need forms the basis for ingesting carbohydrate at 30-60 grams per hour during exercise. In laboratory simulations of performance, athletes fatigue due to hyperthermia when esophageal is approximately 40 degrees C, in association with near maximal heart rate and perceived exertion. It is likely that the central nervous system is involved in the aetiology of fatigue from hyperthermia. Dehydration during exercise promotes hyperthermia by reducing skin blood flow, sweating rate and thus heat dissipation. The combination of dehydration and hyperthermia during exercise causes large reductions in cardiac output and blood flow to the exercising musculature, and thus has a large potential to impair endurance performance. Endurance performance is optimized when training is aimed specifically at developing individual components of the model presented and nutritional supplementation prevents hypoglycemia and attenuates dehydration and hyperthermia. Indeed, the challenge at the transition to a new millennium is to synergistically integrate these physiological factors in training and competition.
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PMID:Physiological determinants of endurance exercise performance. 1066 57

Farnesyl protein transferase (FT), an enzyme that catalyzes the first step in the posttranslational modification of ras and a number of other polypeptides, has emerged as an important target for the development of anticancer agents. SCH66336 is one of the first FT inhibitors to undergo clinical testing. We report a Phase I trial to assess the maximum tolerated dose, toxicities, and biological effectiveness of SCH66336 in inhibiting FT in vivo. Twenty patients with solid tumors received 92 courses of escalating SCH66336 doses given orally twice a day (b.i.d.) for 7 days out of every 3 weeks. Gastrointestinal toxicity (nausea, vomiting, and diarrhea) and fatigue were dose-limiting at 400 mg of SCH66336 b.i.d. Moderate reversible renal insufficiency, secondary to dehydration from gastrointestinal toxicity, was also seen. Inhibition of prelamin A farnesylation in buccal mucosa cells of patients treated with SCH66336 was demonstrated, confirming that SCH66336 inhibits protein farnesylation in vivo. One partial response was observed in a patient with previously treated metastatic non-small cell lung cancer, who remained on study for 14 months. This study not only establishes the dose for future testing on this schedule (350 mg b.i.d.) but also provides the first evidence of successful inhibition of FT in the clinical setting and the first hint of clinical activity for this class of agents.
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PMID:A Phase I trial of the farnesyl transferase inhibitor SCH66336: evidence for biological and clinical activity. 1076 74

Snowboarding is now a well-established winter sport and a popular mode of mountaineering. In-area and backcountry snowboarding are defined, as well as a new term, glisse, that refers to all types of skis and snowboards. New developments in equipment focus on boot and binding systems. Backcountry travel is highlighted, including ascent with snowshoes, skis, a splitboard, and crampons. Injuries are about 4-6 per 1000 snowboarding days. Upper extremity injuries are most often wrist sprains or fractures. Lower extremity injuries are primarily ankle sprains and are generally less severe than knee injuries in skiers. Fracture to the lateral process of the talus has been called snowboarder's fracture. Backcountry injuries include avalanche suffocation and trauma, deep snow immersion asphyxiation, hypothermia, frostbite, dehydration, fatigue, acute mountain sickness, and sunburn. Specific recommendations for prevention and safety are discussed.
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PMID:In-area and backcountry snowboarding: medical and safety aspects. 1251 Jul 87

We present a case of villous adenoma of the rectum, associated with severe fluid imbalance in a 69 year-old, previously healthy woman. Severe dehydration with hyponatraemia, hypokalaemia, acidosis/alkalosis and watery diarrhoea is typical. Clinical presentation may include fatigue, confusion, convulsions or coma. Intensive rehydration is the primary intervention, and causal treatment is always surgery. Normally full recovery is achieved.
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PMID:[Villous adenoma of the rectum with electrolyte imbalance. McKittrick-Wheelock syndrome]. 1096 48


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