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Query: UMLS:C0392674 (exhaustion)
 13,658 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of low blood glucose concentration during low-intensity prolonged physical exercise on the hypothalamus-pituitary-adrenocortical axis were investigated in healthy young men. In experiment 1, six subjects who had fasted for 14 h performed bicycle exercise at 50% of their maximal O2 uptake until exhaustion. At the end of the exercise, adrenocorticotropic hormone (ACTH) and cortisol increased significantly. However, this hormonal response was totally abolished when the same subjects exercised at the same intensity while blood glucose concentrations were maintained at the preexercise level. In experiment 2, in addition to ACTH and cortisol, the possible changes in plasma concentration of corticotropin-releasing factor (CRF) were investigated during exercise of the same intensity performed by six subjects. As suggested by a previous study (Tabata et al. Clin. Physiol. Oxf. 4: 299-307, 1984), when the blood glucose concentrations decreased to less than 3.3 mM, plasma concentrations of CRF, ACTH, and cortisol showed a significant increase. At exhaustion, further increases were observed in plasma CRF, ACTH, and cortisol concentrations. These results demonstrate that decreases in blood glucose concentration trigger the pituitary-adrenocortical axis to enhance secretion of ACTH and cortisol during low-intensity prolonged exercise in humans. The data also might suggest that this activation is due to increased concentration of CRF, which was shown to increase when blood glucose concentration decreased to a critical level of 3.3 mM.
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PMID:Effect of low blood glucose on plasma CRF, ACTH, and cortisol during prolonged physical exercise. 166 96

The purpose of this study was to investigate the effects of physical training on the responses of serum adrenocorticotropic hormone (ACTH) and cortisol concentration during low-intensity prolonged exercise. Five subjects who had fasted for 12 h cycled at the same absolute intensity that elicited 50% of pre-training maximal oxygen uptake (VO2max), either until exhaustion or for up to 3 h, before and after 7 weeks of vigorous physical training [mean daily energy consumption during training exercise, 531 kcal (2230 kJ)]. In the pretraining test, serum ACTH and cortisol concentrations did not increase during the early part of the exercise. Increases in concentrations of both hormones occurred in all subjects when blood glucose concentration decreased during the later phase of the exercise. The mean values and SEM of serum ACTH and cortisol concentrations at the end of the exercise were 356 ng.l-1, SEM 79 and 438 micrograms.l-1, SEM 36, respectively. After the physical training, VO2max of the subjects improved significantly from the mean value of 50.2 ml.kg-1.min-1, SEM 2.5 to 57.3 ml.kg-1.min-1, SEM 2.0 (P less than 0.05). In the post-training test, exercise time to exhaustion was prolonged in three subjects. Comparing the pre- and post training values observed after the same length of time that the subjects had exercised in the pre-training test, the post-training values of serum ACTH (44 ng.l-1, SEM 3) and cortisol (167 micrograms.l-1, SEM 30) concentration were less than the pre-training value (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of physical training on the responses of serum adrenocorticotropic hormone during prolonged exhausting exercise. 217 89

Eight healthy young men were studied during three periods of heat exposure in a Finnish sauna bath: at 80 degrees C dry bulb (80 D) and 100 degrees C dry bulb (100 D) temperatures until subjective discomfort, and in 80 degrees C dry heat, becoming humid (80 DH) until subjective exhaustion. Oral temperature increased 1.1 degrees C at 80 D, 1.9 degrees C at 100 D and 3.2 degrees C at 80 DH. Heart rate increased about 60% at 80 D, 90% at 100 D and 130% at 80 DH. Plasma noradrenaline increased about 100% at 80 D, 160% at 100 D and 310% at 80 DH. Adrenaline did not change. Plasma prolactin increased 2-fold at 80 D, 7-fold at 100 D and 10-fold at 80 DH. Blood concentrations of the beta-endorphin immunoreactivity at 100 D, adrenocorticotropic hormone (ACTH) at 100 D and 80 DH, growth hormone at 100 D and testosterone at 80 DH also increased, but cortisol at 80 D and 100 D decreased. The plasma prostaglandin E2 and serum thromboxane B2 levels did not change. Patterns related to heat exposure were observed for heart rate, plasma noradrenaline, ACTH and prolactin in the three study periods.
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PMID:Haemodynamic and hormonal responses to heat exposure in a Finnish sauna bath. 275 81

The aim of the present investigation was to compare the changes in plasma estradiol (E2), progesterone (P), luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), androstenedione (delta 4-A), dehydroepiandrosterone sulfate (DHEA-S), adrenocorticotropic hormone (ACTH), and prolactin (PRL) in standardized tests (15-min consecutive work loads of 60%, 70%, 80% VO2 max to exhaustion) in 13 eumenorrheic untrained (UT) and 8 highly trained women (MR). Blood was obtained 15 and 2 min before exercise and at the end of each work load or each 15 min period. The results showed a significant increase (0.05 greater than P less than 0.001, two-way ANOVA) in plasma E2 P, T delta 4-A, PRL, and ACTH both in UT and MR irrespective of the phase of the menstrual cycle. DHEA S levels increased significantly in the MR, but not in the UT, PRL and ACTH increased linearly with exercise in MR and nonlinearly in UT. In the latter group, only the 80% VO2 max work load was able to elicit significant increments in the plasma levels of these hormones. In the MR plasma T and delta 4-A levels increased relatively more pronounced (P less than 0.05) at comparable work loads and exercise times than in the UT. LH levels decreased with exercise both in the UT and MR, whereas FSH levels remained unchanged (MR) or decreased (UT). These findings suggest that during exercise the ovarian hormones are increased by more unspecific mechanisms such as a decreased metabolic clearance rate, whereas in the MR, adrenal secretion of androgens is enhanced.
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PMID:Multiple hormonal responses to physical exercise in eumenorrheic trained and untrained women. 342 89

The present study examined whether benzodiazepine (BZ) intake alters performance and selected hormonal and metabolic variables during submaximal exercise. Seven triathletes completed two cycling trials at 85% maximum O2 uptake starting 3 h after an ingestion of either a placebo (PLA) of gelatin or BZ (1.5 mg lorazepam) and continuing until exhaustion, according to a double-blind randomized protocol. Blood samples were collected at rest; 5, 10, and 15 min; and exhaustion for dopamine (DA), norepinephrine (NE), epinephrine (Epi), adrenocorticotropic hormone (ACTH), cortisol (CORT), insulin (INS), free fatty acid, blood glucose, and lactate (La) determinations. Time of cycling was not significantly changed after BZ or PLA administration (22.9 +/- 2.5 vs. 23.5 +/- 3.8 min, respectively). A decrease in CORT and an increase in INS (P < 0.05) were observed with BZ before cycling. In comparison with rest, exercise resulted in a decrease in INS and an increase in all the other variables investigated (P < 0.001), but DA, NE, Epi, ACTH, CORT, La, and free fatty acid were significantly less elevated under BZ (P < 0.05). No change was found in glucose and INS levels between the two treatments at the end of the test. There was a strong correlation under both PLA and BZ conditions between DA, NE, Epi, and ACTH and also between Epi and La levels. From these data, BZ intake did appear to alter metabolism but did not influence performance during intense submaximal exercise.
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PMID:Performance and metabolic effects of benzodiazepine during submaximal exercise. 800 35

Investigations of exercise-induced increases in beta-endorphin, adrenocorticotropic hormone (ACTH) and cortisol concentration have been carried out mainly in men. Data concerning the female reaction are sparse and less clear. In a comparison between incremental exercise and marathon running 14 experienced female marathon runners volunteered to run to exhaustion according to an incremental treadmill protocol. They ran a marathon 4 weeks later. Blood was analysed for beta-endorphin, ACTH and cortisol concentration immediately prior to the laboratory treadmill test, 3, 30 and 60 min later, as well as prior to the marathon, after 60 min and 120 min of running and 3, 30 min, and 24 h after completion of the run. At each blood collection, lactate concentration, heart frequency and perceived exertion were determined. The mean marathon running time was 3.22 h. Baseline concentrations for beta-endorphin of 22 pmol.l-1 before the marathon and 19 pmol.l-1 before the treadmill exercise increased 1.4-fold 30 min after the marathon and 1.9-fold after the treadmill exercise; for ACTH the baseline of 4.7 and 4.0 pmol.l-1 was increased by 8.3- and 10.3-fold, respectively. Cortisol concentration rose exponentially from a baseline 17 micrograms.dl-1 and peaked at 2.2-fold 30 min after the run, when the maximal concentration also had been reached after the treadmill test, increasing 1.3-fold from a baseline of 21 micrograms.dl-1. The maximal values for cortisol concentration after both exercises differed from each other, while the maxima of ACTH and beta-endorphin concentrations were similar. The ACTH and beta-endorphin concentration declined more slowly during the recovery after the marathon than after the treadmill. Cortisol concentration was below baseline 24 h later. In comparison with men studied earlier, female marathon runners showed higher baseline concentrations and lesser increases in beta-endorphin and lower baseline concentrations and larger increases in ACTH concentration after both types of exercise. The delayed decrease in concentration of the hormones after the marathon was similar in male and female runners.
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PMID:beta-Endorphin and adrenocorticotrophin after incremental exercise and marathon running--female responses. 892 11

The aim of the present prospective longitudinal study was to investigate the hormonal response in overtrained athletes at rest and during exercise consisting of a short-term exhaustive endurance test on a cycle ergometer at an intensity 10% above the individual anaerobic threshold. Over a period of 19+/-1 months, 17 male endurance athletes (cyclists and triathletes; age 23.4+/-1.6 yr; VO2max. 61.2+/-1.8 mL x min(-1) x kg(-1); means+/-SEM) were examined five times on two separate days under standardized conditions. Short-term overtraining states (OT, N=15) were primarily induced by an increase of frequency of high-intensive bouts of exercise or competitions without increase of the total amount of training. OT was compared with normal training states intraindividually (NS, N=62). During OT, the time to exhaustion of the exercise test was significantly decreased by 27% on average. At rest and during exercise, the concentrations in plasma and the nocturnal excretion in urine of free epinephrine and norepinephrine were not significantly changed during OT. At physical rest, the concentrations of (free) testosterone, cortisol, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone, growth hormone, and insulin during OT were comparable with those during NS. A significantly (P < 0.025) lower maximal exercise-induced increase of the adrenocorticotropic hormone and growth hormone, as well as a trend for a decrease of cortisol (P=0.060) and insulin (P=0.036), was measured. The response of free catecholamines as well as the ergometric performance of an all-out 30-s test was unchanged. Serum urea, uric acid, ferritin, and activity of creatine kinase showed no differences between conditions. In conclusion, the results confirm the hypothesis of a hypothalamo-pituitary dysregulation during OT expressed by an impaired response of pituitary hormones to exhaustive short-endurance exercise.
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PMID:Impaired pituitary hormonal response to exhaustive exercise in overtrained endurance athletes. 952 87

Effects of a serotonin re-uptake inhibitor and oral amino acid supplementations on physical and mental performance as well as neuroendocrine variables were investigated. 10 male subjects cycled in four trials until exhaustion. Participants ingested a placebo in trial (T) I, 20 mg paroxetine in T II, 21 g branched-chain amino acids (BCAA) in T III and 20g tyrosine (TYR) in T IV. Heart rate, capillary lactate, plasma insulin, free fatty acids, glucose, serotonin and beta-endorphin did not differ in trials. Plasma ammonia increments during exercise were higher in T III. Plasma BCAA in T III and plasma TYR in T IV were increased after 30 min of exercise according to the supplemented substances. In contrast to all other trials, the ratio of plasma free TRP/BCAA did not increase in T III. Plasma TYR/BCAA was augmented in T IV and decreased in T III after 30 min of exercise, whereas it did not change in T I and II. Plasma prolactin (PRL), growth hormone, cortisol, adrenocorticotropic hormone, norepinephrine and epinephrine increased during all trials. Plasma PRL increments were higher in T IV. Exhaustion was reached earlier in T II. No significant differences were found between other trials. Drive during psychometric testing subsequent to exercise was improved in T III and IV. The results indicate that fatigue during endurance exercise was increased by pharmacological augmentation of the brain serotonergic activity. However, a reduction of 5-HT synthesis via BCAA supplementation did not affect physical fatigue. TYR administration did not alter physical performance either although plasma PRL increments suggest that changes in the monoaminergic system were induced. Precaution is necessary before assuming an ergogenic value of amino acids.
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PMID:Influence of paroxetine, branched-chain amino acids and tyrosine on neuroendocrine system responses and fatigue in humans. 962 32

The multitude of publications regarding overtraining syndrome (OTS or 'staleness') or the short-term 'over-reaching' and the severity of consequences for the athlete are in sharp contrast with the limited availability of valid diagnostic tools. Ergometric tests may reveal a decrement in sport-specific performance if they are maximal tests until exhaustion. Overtrained athletes usually present an impaired anaerobic lactacid performance and a reduced time-to-exhaustion in standardised high-intensity endurance exercise accompanied by a small decrease in the maximum heart rate. Lactate levels are also slightly lowered during submaximal performance and this results in a slightly increased anaerobic threshold. A reduced respiratory exchange ratio during exercise still deserves further investigation. A deterioration of the mood state and typical subjective complaints ('heavy legs', sleep disorders) represent sensitive markers, however, they may be manipulated. Although measurements at rest of selected blood markers such as urea, uric acid, ammonia, enzymes (creatine kinase activity) or hormones including the ratio between (free) serum testosterone and cortisol, may serve to reveal circumstances which, for the long term, impair the exercise performance, they are not useful in the diagnosis of established OTS. The nocturnal urinary catecholamine excretion and the decrease in the maximum exercise-induced rise in pituitary hormones, especially adrenocorticotropic hormone and growth hormone, and, to a lesser degree, in cortisol and free plasma catecholamines, often provide interesting diagnostic information, but hormone measurements are less suitable in practical application. From a critical review of the existing overtraining research it must be concluded that there has been little improvement in recent years in the tools available for the diagnosis of OTS.
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PMID:Diagnosis of overtraining: what tools do we have? 1181 95

The effects of a 1-month exercise program and magnesium supplementation on the adrenocorticotropic hormone and cortisol levels were studied in young tae-kwon-do and sedentary subjects both at rest and exhaustion. The hormone levels were compared before and after supplementation with 10 mg of magnesium (as magnesium sulfate) per kilogram of body weight. Both exercise and magnesium supplements caused significant increases of the adrenocorticotropic hormone (p < 0.05). The cortisol levels were increased in training subjects receiving supplements (p < 0.05) but not so in subjects that either trained or received magnesium supplements in an independent manner. The cortisol levels measured in resting individuals were higher in the supplemented and non-supplemented athletes than those in sedentary subjects (p < 0.05). The results of this study show that exercise and/or magnesium supplementation causes a rise of the adrenocorticotropic hormone, whereas cortisol is increased only as a result of combined exhaustion and magnesium supplements.
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PMID:Adrenocorticotropic hormone and cortisol levels in athletes and sedentary subjects at rest and exhaustion: effects of magnesium supplementation. 1799 37


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