Plasma volume (PV) decreases at high altitude, but is rapidly restored upon return to sea-level (RSL). The aim of this study was (1) to describe PV recovery upon RSL with concomitant changes in major fluid regulating hormones, and (2) to test the hypothesis that PV recovery is promoted by the ...

Plasma interleukin-6 (IL-6) concentration has been shown to increase with exercise and various cell types and tissues have been suggested to be responsible for this increase. At present no studies have measured the interstitial concentration of IL-6 in skeletal muscle and connective tissue. The present study represents the first attempt ...

The objective of the present study was to measure plasma endothelin-1 (ET-1) at rest and during exercise in the horse. Six healthy, Standardbred and Thoroughbred mares (5.3+/-0.8 years; 445.2+/-13.1 kg) which were unfit, but otherwise accustomed to running on the treadmill, were used in the study. Plasma ET-1 concentrations were ...

To determine the effects of exercise, high heat and humidity and acclimation on plasma adrenaline, noradrenaline, beta-endorphin and cortisol concentrations, five horses performed a competition exercise test (CET; designed to simulate the speed and endurance test of a three-day event) in cool dry (CD) (20 degrees C/40% RH) and hot ...

The inhibition of catechol-O-methyltransferase (COMT) may impair catecholamine clearance resulting in unwanted cardiac and hemodynamic events. We therefore studied the effects of entacapone, an inhibitor of peripheral COMT, on cardiorespiratory and plasma noradrenaline (NA) responses to exercise and on respiratory muscle strength in l-dopa treated patients with Parkinson's disease (PD). ...

Adrenomedullin (ADM) release is enhanced in pheochromocytoma, chronic heart failure (HF), hypertension and renal diseases. This study was designed to test the hypothesis that ADM secretion increases also in response to acute stimuli, such as static effort and to compare plasma ADM response to this stimulus in patients with chronic ...

Rigorous bed rest (RBR) induces significant biochemical and circulatory changes. However, little is known about acute rigorous bed rest (ARBR). Measuring biochemical and circulatory variables during ARBR and RBR the aim of this study was to establish the significance of ARBR effect. Studies were done during 3 days of a ...

Increases in the concentration of interstitial potassium concentration during exercise may play a role in the modulation of the cardiovascular response to exercise. However, it is not known if changes in potassium correlate with indexes of muscle reflex engagement. Eight healthy subjects performed dynamic [rhythmic handgrip (RHG)] and static handgrip ...

We investigated the effect of hypothyroidism in dogs on (1) the Na+-, K+ -ATPase concentration in skeletal muscle, and (2) potassium (K+) homeostasis at rest and during exercise. Prior to and 1 year after induction of hypothyroidism by surgery and subsequent radiothyroidectomy, the Na+-, K+ -ATPase concentrations were quantified in ...

The purpose of this study was to determine the effects of alkalosis on epinephrine concentrations in response to a 90 s maximal exercise test. A group of ten healthy men ingested either a bicarbonate (BS) supplement (0.3 g x kg(-1) of body mass of sodium bicarbonate) or placebo mixture (P) ...

The present study was designed to determine whether exercise plasma noradrenaline (NA) levels could predict cardiac death in patients with mild heart failure in whom the plasma NA levels were only minimally elevated. Treadmill exercise testing with serial measurement of plasma NA and plasma adrenaline were performed in 142 patients ...

BACKGROUND: To compare plasma lactate concentrations and plasma lactate kinetics during recovery, for measured and corrected values for changes in plasma volume, after a maximal aerobic exercise. METHODS: Sixteen male subjects performed an incremental and maximal exercise in order to reach maximal aerobic power. Prior to the exercise, at the ...

BACKGROUND/AIM: Hyperkalemic responses to both physical exercise and alpha-adrenergic stimulation are enhanced in patients with terminal renal failure. Alpha-adrenergic blockade was found to protect against hyperkalemia during vigorous exercise in healthy men. The aim of the study was to examine the effects of the alpha-adrenergic blocker doxazosin on exercise-induced hyperkalemia ...

The exercise-induced increase and post-exercise decrease of plasma hyaluronan concentration were studied in human subjects. Six well trained men performed incremental exercise until exhaustion (MAX), intensive (submaximal, SUB) and extensive exercise (moderate, MOD) on a bicycle ergometer, defined as work at 100, 77 and 50% of maximal oxygen consumption. Hyaluronan ...

Intercellular adhesion molecule-1 (ICAM-1) plays an important role in leukocyte migration from the circulation and intervention at sites of inflammation. We investigated the effects of various types of exercise on circulating levels of soluble ICAM-1 (sICAM-1) in normal healthy male adults. Plasma concentrations of sICAM-1 were measured before and after ...

The effect of hydration status on performance has not been adequately emphasized or examined in swimmers. Theoretically, moderate overhydration might reduce the proportionate fluid loss from the circulation during exercise of this nature. To explore this issue, 11 (5 women, 6 men) collegiate swimmers swam 2 183-m (200-yd) time trials ...

Plasma corticosterone, glucose, and testosterone concentrations were measured in wild, immature specimens of the highly endangered Kemp's ridley sea turtle (Lepidochelys kempii) to determine effects of acute handling stress. Thirty-nine free-ranging turtles were captured by entanglement net near the Cedar Keys, Florida. Blood samples were collected immediately after retrieval from ...

The aim of this study was to investigate the involvement of the antilipolytic alpha(2)-adrenergic receptor pathway in the regulation of lipolysis during exercise in subcutaneous abdominal adipose tissue (SCAAT). Seven trained men and 15 untrained men were studied. With the use of microdialysis, the extracellular glycerol concentration was measured in ...

We tested the hypothesis that renal tubular Na(+) reabsorption increased during the first 24 h of exercise-induced plasma volume expansion. Renal function was assessed 1 day after no-exercise control (C) or intermittent cycle ergometer exercise (Ex, 85% of peak O(2) uptake) for 2 h before and 3 h after saline ...

BACKGROUND: The study investigated the concentrations of plasma catecholamine, adrenaline (A) and noradrenaline (NA), and the adrenal medulla responsiveness to the sympathetic nervous activity in sprinters (S), endurance runners (E) and untrained subjects (U) during a supramaximal exercise (the Wingate-test). METHODS: A group of 19 men took part in the ...

Exercise induces increased levels of plasma interleukin-6 (IL-6) as well as changes in the concentration of lymphocytes and neutrophils. The aim of this study was to investigate a possible role for epinephrine. Seven healthy men participated in an exercise experiment. One month later they received an epinephrine infusion. The exercise ...

The effects of hydromineral hormones and catecholamines on renal water and electrolyte excretion were examined during and after dehydration induced by either passive heat or exercise. Eight healthy young Caucasian subjects participated in three separate trials, each including three consecutive phases. Phases 1 and 3 involved a 90-min period at ...

The cardiovascular and metabolic responses to supine leg exercise were measured in 9 healthy subjects (controls) and in 19 subjects with two primary forms of autonomic failure (11 with peripheral sympathetic denervation [pure autonomic failure; PAF], 8 with central sympathetic failure [multiple system atrophy; MSA]). With exercise, blood pressure increased ...

BACKGROUND: Hypothermia, commonly used for organ protection during cardiopulmonary bypass (CPB), has been associated with changes in plasma volume, hemoconcentration and microvascular fluid shifts. Fluid pathophysiology secondary to hypothermia and the mechanisms behind these changes are still largely unknown. In a recent study we found increased fluid needs during hypothermic ...

The purpose of this study was to evaluate the pharmacokinetics (PK) profile of oral levofloxacin in human immunodeficiency virus-positive patients in steady-state treatment with nelfinavir (NFV) or with efavirenz (EFV) and to determine the effects of levofloxacin on the PK parameters of these two antiretroviral agents. For levofloxacin, plasma samples ...

Several recent reports indicate that exercise elevates the plasma interleukin 6 levels; however, the precise regulation of such an elevation still remains to be clarified. In this study, in order to clarify the requirements of central and peripheral catecholaminergic system for this exercise-induced interleukin 6 elevation, rats were either intraperitoneally ...

A highly sensitive time-resolved fluoroimmunoassay of human plasma cytokines is described. The cytokines such as interleukin-1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF alpha) are known to be acute inflammatory cytokines and it has been reported that these cytokines are secreted into blood by physical exercise. In this study, ...

This study investigated the effect of different exercise bouts on plasma leptin response. Trained men (n = 9) performed a short duration, maximal intensity (MAX) bout and a 60-min endurance run at approximately 70% of maximal oxygen consumption (END). Blood was collected before, immediately after, 24 h after (24 h ...

Strenuous endurance exercise in fasted subjects is accompanied by increased plasma levels of catecholamines, leucocytosis, low insulin, and elevated plasma free fatty acids (FFA). Immediately after such exercise, plasma FFA may rise to high and potentially harmful levels, whereas the white blood cell count (WBCC) rapidly decreases towards or below ...

BACKGROUND: Postexercise proteinuria is a common phenomenon depending on hypothetical mechanisms such as the hemodynamic system and its sympathetic component. To test this hypothesis we administrated an a2-adrenergic agonist (clonidine) in order to reduce the catecholamine response during exercise. METHODS: Clonidine (300 mg) and a placebo, one week apart, were ...

In accordance with Stewart's physicochemical approach, the three independent determinants of plasma hydrogen ion concentration ([H(+)]) were measured at rest and during exercise in the follicular (FP) and luteal phase (LP) of the human menstrual cycle. Healthy, physically active women with similar physical characteristics were tested during either the FP ...

The present study examined the influence of ingesting a moderate dose of alcohol on the main determinants of blood rheology namely: plasma viscosity, plasma fibrinogen concentration, plasma total protein concentration, and haematocrit. Eleven moderately active young men were studied immediately after a standardised cycle ergometer test and during the 24 ...

Dehydration leads to the aggravation of gastrointestinal (GI) complaints during exercise. The aim of this study was to examine the effect of dehydration on various GI parameters during strenuous exercise. Ten healthy well-trained men were investigated in dehydrated and in euhydrated conditions. Dehydration took place before the experiments using a ...

The present study investigated the effect of active recovery (AR) as compared to rest recovery (RR) upon FFA concentrations following moderate- (MI) or high-intensity (HI) running. Fourteen well-trained males (23.7 +/- 6 years, VáO2max = 69.5 +/- 1.8ml á min-1 kg-1) were randomly assigned into two trials (HI = 30 ...

A pulse ([(14)C]palmitate)-chase ([(3)H]palmitate) approach was used to study intramuscular triglyceride (imTG) fatty acid and plasma free fatty acid (FFA) kinetics during exercise at approximately 45% peak O(2) consumption in 12 adults. Vastus lateralis muscle was biopsied before and after 90 min of bicycle exercise; (3)H(2)O production, breath (14)CO(2) excretion ...

Orthostatic intolerance (OI) is the most serious symptom of cardiovascular deconditioning induced by head-down bed rest or weightlessness. Wearing venoconstrictive thigh cuffs is an empirical countermeasure used by Russian cosmonauts to limit the shift of fluid from the lower part of the body to the cardio-cephalic region. Our aim was ...

Our purpose was to study the interaction between Na(+) content and fluid volume on rehydration (RH) and restoration of fluid spaces and cardiovascular (CV) function. Ten men completed four trials in which they exercised in a 35 degrees C environment until dehydrated by 2. 9% body mass, were rehydrated for ...

According to the limited information available, exercise has no substantial effect on the absorption of orally given drugs. However, it appears to enhance absorption from intramuscular, subcutaneous, transdermal and inhalation sites. The effects of exercise on drug distribution are complex. Exercise increases muscular blood flow resulting, for example, in the ...

The aim of our study was to evaluate the influence of low-intensity exercise on levodopa absorption and levodopa motor effect. We studied the pharmacokinetics and pharmacodynamics of levodopa under resting conditions and under a workload of 50 watts for 2 hours on a cycle ergometer in 12 parkinsonian patients with ...

BACKGROUND: Patients with diabetes mellitus have an altered exercise plasma catecholamine response, which may be related to the abnormal sympathoadrenal function and autonomic neuropathy. Presence of autonomic neuropathy is associated with poor prognosis, but relationship between exercise plasma catecholamine and prognosis has not been investigated. This study determined if altered ...

We have previously shown that serum gonadotropins, particularly LH, decline after acute exercise in male volunteers. The mechanism for this decline is unknown. Plasma leptin and IGF-I concentrations were measured in seven male volunteers after acute exercise to exhaustion using the Bruce protocol. Leptin concentrations declined following exercise reaching nadir ...

It has been reported that plasma choline levels decrease following certain types of strenuous exercise. Preliminary findings also suggest that a drop in plasma choline may limit physical performance, while choline supplementation may delay fatigue during prolonged efforts. A double-blind crossover design was used to determine the relationship between plasma ...

The aim of this study was to test the hypothesis that post-exercise hypotension was the mechanism for the plasma volume and albumin gain during recovery. Seven healthy young men completed two experiments (> or =1 week apart) to exercise continuously at 65% of peak aerobic capacity for 60 min followed ...

The aim of this study was to investigate the effect of strenuous exercise on plasma nitric oxide and iron (PI) concentrations in rats. The rats were divided into six groups: 3, 6 and 12 months of the exercise (swimming) groups and their corresponding controls. At the end of experimental periods, ...

Experimental studies investigating the effects of exercise on plasma total homocyst(e)ine (H[e]) levels in humans are almost non-existent. H(e) has been demonstrated to represent an independent risk factor for cardiovascular disease. The exact mechanism through which H(e) exerts its effects on the arteries is unknown but it is thought to ...

PURPOSE: We investigated the effects of acute plasma volume expansion on exercise performance in the heat. METHODS: Six moderately trained men cycled for 40 min at 64 +/- 2% peak pulmonary oxygen uptake (VO2peak) followed by an individual performance time trial, where subjects completed a set amount of work (267 ...

The goal of the study was to examine whether lipid mobilization from adipose tissue undergoes changes during repeated bouts of prolonged aerobic exercise. Microdialysis of the subcutaneous adipose tissue was used for the assessment of lipolysis; glycerol concentration was measured in the dialysate leaving the adipose tissue. Seven male subjects ...

The acid-base status of venous blood was studied in 17 show jumpers before and after exercise using both a traditional and a quantitative approach. Partial pressure of carbon dioxide (PCO(2)), pH, haemoglobin, and plasma concentrations of sodium (Na(+)), chloride (Cl(-)), potasium (K(+)), ionized calcium (Ca(2+)), total proteins, albumin, lactate and ...

This study determined the effects of elevated plasma epinephrine on fat metabolism during exercise. On four occasions, seven moderately trained subjects cycled at 25% of peak oxygen consumption (VO(2 peak)) for 60 min. After 15 min of exercise, subjects were intravenously infused with low (0.96 +/- 0.10 nM), moderate (1.92 ...

Consumption of low glycemic index (GI) foods before submaximal endurance exercise may be beneficial to performance. To test whether this may also be true for high intensity exercise, 10 trained cyclists began an incremental exercise test to exhaustion 65 min after consuming equal carbohydrate portions of glucose (HGI), pasta (LGI), ...