Arterial blood pressure regulation during prolonged isometric exercise in artistic gymnastic athletes compared to controls.

Background: The aim of this cross-sectional study was to examine the baroreflex sensitivity alterations in regulating arterial blood pressure during prolonged isometric exercise at different intensities in elite artistic gymnastic athletes compared to non-athletes.

Methods: Fourteen young males participated in the study; 7 international level artistic gymnastics athletes and 7 physically active students inexperienced to isometric or resistance training. On two occasions, both groups performed 3 minutes of isometric handgrip exercise either at 30% or 50% of maximum voluntary contraction (MVC), in a randomized order.

On the mechanisms of stress-induced human spleen contraction: training for a higher blood oxygen-carrying capacity.

Despite its comparatively limited size in humans, spleen has been shown able to expel red-blood cells in the circulation and thus augment blood oxygen-carrying capacity under certain physiologic conditions. In the present state-of-the-art review, the short- and long-term regulation of spleen volume will be discussed. With regards to the physiological mechanism underlying spleen contraction, sympathetic activation stands as the prime contributor to the response.

The Effect of Skeletal Muscle Oxygenation on Hemodynamics, Cerebral Oxygenation and Activation, and Exercise Performance during Incremental Exercise to Exhaustion in Male Cyclists.

This study aimed to elucidate whether muscle blood flow restriction during maximal exercise is associated with alterations in hemodynamics, cerebral oxygenation, cerebral activation, and deterioration of exercise performance in male participants. Thirteen healthy males, cyclists (age 33 ± 2 yrs., body mass: 78.

The effect of menstrual cycle on maximal breath-hold time.

This study investigated the effect of menstrual cycle phase on breath-hold time (BHT). Twelve healthy females, aged 18-30 yrs, with regular menstrual cycles, without breath-hold (BH) experience, performed a BH protocol which included eight repeated maximal efforts with face immersion in cool water separated by 2-min intervals in two different phases of menstrual cycle; early follicular (EF) phase and midluteal (ML) phase. Respiratory, cardiovascular and hematological responses were studied before, during and after BH efforts.

Thermoregulatory and cardiovasculareffects of capsaicin application on human skin during dynamic exercise to temperate and warm conditions.

Thermoregulatory and cardiovascular responses during cycling in temperate and warm environments without and with application of capsaicin on the skin were investigated. We hypothesized that regardless of environmental temperature, capsaicin application would activate heat loss mechanisms attenuating exercise-induced rectal temperature (Tre) and blood pressure increase. Eight males cycled at 55% of their maximal aerobic power so long as to reach 38.

No ergogenic effects of a 10-day combined heat and hypoxic acclimation on aerobic performance in normoxic thermoneutral or hot conditions.

Purpose: Hypoxic acclimation enhances convective oxygen delivery to the muscles. Heat acclimation-elicited thermoregulatory benefits have been suggested not to be negated by adding daily exposure to hypoxia. Whether concomitant acclimation to both heat and hypoxia offers a synergistic enhancement of aerobic performance in thermoneutral or hot conditions remains unresolved.

Effects of capsaicin application on the skin during resting exposure to temperate and warm conditions.

We investigated thermoregulatory and cardiovascular responses at rest in a temperate (20°C) and in a warm (30°C) environment (40% RH) without and with the application of capsaicin on the skin. We hypothesized that regardless of environmental temperature, capsaicin application would stimulate heat loss and concomitantly deactivate heat conservation mechanisms, thus resulting in rectal temperature (Tre) and mean blood pressure decline due to excitation of heat-sensitive TRPV1. Ten male subjects were exposed, while seated, for 30 minutes to 20.

Effect of gender on maximal breath-hold time.

This study examined the effect of gender on breath-hold time (BHT). Sixteen healthy subjects, eight males (M) and eight females (F), aged 18-30 years, without breath-hold (BH) experience, performed: (a) a pulmonary function test, (b) an incremental cycle ergometer test to exhaustion and (c) a BH protocol, which included eight repeated maximal efforts separated by 2-min intervals on two occasions: without (BHFOI) and with face immersion (BHFI) in cool water (14.8 ± 0.

The effect of exercise-induced hypoxemia on blood redox status in well-trained rowers.

Exercise-induced arterial hypoxemia (EIAH), characterized by decline in arterial oxyhemoglobin saturation (SaO(2)), is a common phenomenon in endurance athletes. Acute intensive exercise is associated with the generation of reactive species that may result in redox status disturbances and oxidation of cell macromolecules. The purpose of the present study was to investigate whether EIAH augments oxidative stress as determined in blood plasma and erythrocytes in well-trained male rowers after a 2,000-m rowing ergometer race.

The effect of menthol application to the skin on sweating rate response during exercise in swimmers and controls.

We tested the hypothesis that menthol application would reduce the magnitude and initiation of sweating via excitation of cold-sensitive afferent pathways and concurrently via a cross-inhibition of heat loss pathways in acclimatized (swimmers, SW) and non acclimatized (control, CON) subjects in cool water. It was expected this effect to be exaggerated in SW subjects. Eight SW and eight CON subjects cycled at 60% of their VO(2)max, as long as to reach 38 degrees C in rectal temperature (Tre), without or with (4.

Oxygen saturation in the triceps brachii muscle during an arm Wingate test: the role of training and power output.

The purpose of this study was to investigate the role of training and power output on muscle oxygen desaturation during and resaturation after an arm Wingate test (WAnT). Two groups of subjects were studied; the first group consisted of nine athletes participating in upper arm anaerobic sports and the second group of 11 university students. As a consequence, the group of athletes (HP) produced higher peak and mean power output (p < 0.

Anaerobic capacity of the upper arms in top-level team handball players.

Purpose: Handball is a sport with high anaerobic demands in lower body as has been indicated by Wingate test (WT) performed with the legs, but there are no data available concerning power production during a WT performed with the arms in handball players (HndP). Therefore, the purpose of this study was to explore the arm anaerobic profile of HndP during a WT.

Methods: Twenty-one elite HndP and 9 physical education students (CON), performed a 30-s arm WT.

Contribution of respiratory muscle blood flow to exercise-induced diaphragmatic fatigue in trained cyclists.

We investigated whether the greater degree of exercise-induced diaphragmatic fatigue previously reported in highly trained athletes in hypoxia (compared with normoxia) could have a contribution from limited respiratory muscle blood flow. Seven trained cyclists completed three constant load 5 min exercise tests at inspired O(2) fractions (FIO2) of 0.13, 0.

Human respiratory muscle blood flow measured by near-infrared spectroscopy and indocyanine green.

Measurement of respiratory muscle blood flow (RMBF) in humans has important implications for understanding patterns of blood flow distribution during exercise in healthy individuals and those with chronic disease. Previous studies examining RMBF in humans have required invasive methods on anesthetized subjects. To assess RMBF in awake subjects, we applied an indicator-dilution method using near-infrared spectroscopy (NIRS) and the light-absorbing tracer indocyanine green dye (ICG).

The role of active muscle mass on exercise-induced cardiovascular drift.

The purpose of this study was to examine the role of active muscle mass on cardiovascular drift (CVdrift) during prolonged exercise. Twelve subjects with peak oxygen uptake (VO2peak) of 3.52 ± 0.

Somatotype, size and body composition of competitive female volleyball players.

The aim of this study was to describe the morphological characteristics of competitive female volleyball players. For this purpose, body weight and height, breadths and girths as well as skinfold thickness at various body sites were assessed in 163 elite female volleyball players (age: 23.8+/-4.

Effects of hypoxia on diaphragmatic fatigue in highly trained athletes.

Previous work suggests that exercise-induced arterial hypoxaemia (EIAH), causing only moderate arterial oxygen desaturation (SaO2 : 92 +/- 1%), does not exaggerate diaphragmatic fatigue exhibited by highly trained endurance athletes. Since changes in arterial O2 tension have a significant effect on the rate of development of locomotor muscle fatigue during strenuous exercise, the present study investigated whether hypoxia superimposed on EIAH exacerbates the exercise-induced diaphragmatic fatigue in these athletes. Eight trained cyclists (VO2max : 67.

Erythropoietin treatment elevates haemoglobin concentration by increasing red cell volume and depressing plasma volume.

Erythropoietin (Epo) has been suggested to affect plasma volume, and would thereby possess a mechanism apart from erythropoiesis to increase arterial oxygen content. This, and potential underlying mechanisms, were tested in eight healthy subjects receiving 5000 IU recombinant human Epo (rHuEpo) for 15 weeks at a dose frequency aimed to increase and maintain haematocrit at approximately 50%. Red blood cell volume was increased from 2933 +/- 402 ml before rHuEpo treatment to 3210 +/- 356 (P < 0.

Importance of hemoglobin concentration to exercise: acute manipulations.

An acute reduction of blood hemoglobin concentration ([Hb]), even when the circulating blood volume is maintained, results in lower (.)V(O(2)(max) and endurance performance, due to the reduction of the oxygen carrying capacity of blood. Conversely, an increase of [Hb] is associated with enhanced (.

Effects of exercise-induced arterial hypoxaemia and work rate on diaphragmatic fatigue in highly trained endurance athletes.

Diaphragmatic fatigue occurs in highly trained athletes during exhaustive exercise. Since approximately half of them also exhibit exercise-induced arterial hypoxaemia (EIAH) during high-intensity exercise, the present study sought to test the hypothesis that arterial hypoxaemia contributes to exercise-induced diaphragmatic fatigue in this population. Ten cyclists ( : 70.