Occupational and recreational noise exposure from indoor arena hockey games.

Occupational and recreational noise exposures were evaluated at two sporting arenas hosting collegiate hockey games (Venue 1) and semi-professional hockey (Venue 2). A total of 54 personal noise dosimetry samples were taken over the course of seven home hockey games: 15 workers and 9 fans at Venue 1, and 19 workers and 11 fans at Venue 2. None of the sampled workers were overexposed to noise based on Occupational Safety and Health Administration criteria.

Noise exposure, characterization, and comparison of three football stadiums.

Personal noise exposure samples were collected from five workers at a large-sized college football stadium and five workers at a medium-sized college football stadium in northern Colorado during three home football games, for a total of 30 personal noise exposures. In addition, personal noise exposure samples were collected from five fans at a National Football League (NFL) stadium, and from two fans at each of the college stadiums during three home football games, for a total of 27 personal noise exposure samples. None of the workers' noise doses were above the Occupational Safety and Health Administration (OSHA) permissible exposure limit of 90 dBA.

Mixed S-nitrosylated polymerized bovine hemoglobin species moderate hemodynamic effects in acutely hypoxic rats.

Hemoglobin (Hb)-based oxygen carriers (HBOCs) are being developed as a potential therapy for increasing tissue oxygenation, yet they have not reached their full potential because of unwanted hemodynamic side effects (vasoconstriction, low cardiac output, and oxygen delivery) due in part to nitric oxide (NO) scavenging by cell-free Hb. It may be possible to overcome the NO scavenging effect by coinfusing S-nitrosylated (SNO) HBOC along with unmodified HBOC. SNO-HBOC, like free Hb, may act as an NO donor in low-oxygen conditions.

Glutaraldehyde-polymerized bovine hemoglobin and phosphodiesterase-5 inhibition.

Objective: Hemoglobin-based oxygen carriers (HBOC) of several types scavenge nitric oxide from the vasculature resulting in vasoconstriction and hypertension, both systemic and pulmonary. Phosphodiesterase-5 (PDE5) inhibitors promote nitric oxide activity and enhance vasodilation. The purpose of this study was to determine whether combined therapy of glutaraldehyde-polymerized bovine hemoglobin (HBOC) with a PDE5 inhibitor would counter the negative hemodynamic consequences of HBOC therapy alone, resulting in improved hemodynamics and oxygen delivery.

Polymerized bovine hemoglobin decreases oxygen delivery during normoxia and acute hypoxia in the rat.

Hemoglobin-based oxygen carriers (HBOC) have been primarily studied for blood loss treatment. More recently infusions of HBOC in euvolemic subjects have been proposed for a wide variety of potential therapies in which increased tissue oxygenation would be beneficial. However, compared with the exchange transfusion models to study blood loss, less is known about HBOC oxygen delivery and vasoacitvity when it is infused in euvolemic subjects.

Airway response during exercise and hyperpnoea in non-asthmatic and asthmatic individuals.

Airway calibre is an important determinant of air flow and respiratory work both at rest and during exercise. While much is understood about control of airway calibre at rest, less is known about the dynamics and changes in airway resistance during exercise, especially in those with asthma. This article provides an overview of the current understanding provided by the literature that has addressed airway resistance during exercise in normal non-asthmatic individuals and in those with asthma.

Dietary salt intake as a potential modifier of airway responsiveness in bronchial asthma.

While pharmacologic treatment of chronic asthma is usually highly effective, medications often have significant side-effects or exhibit tachyphylaxis. Alternative and/or complementary treatments that reduce dependence on pharmacologic medications are of interest in reducing the severity of asthma. This review analyzes the literature that has evaluated dietary salt intake as a potential modifier of the severity of asthma and airway responsiveness.

Comparison of the RT3 Research Tracker and Tritrac R3D accelerometers.

This study compared the RT3 Research Tracker accelerometer to the Tritrac R3D accelerometer in both laboratory and field settings and tested the hypothesis that the RT3 records higher physical activity counts and smaller standard deviations than the R3D. The RT3 is relatively new and untested and its concurrent validity with existing instruments and physical activity needs to be assessed before being used in research. In this study the RT3 had higher average recordings of physical activity counts in all of the nine testing situations than the R3D.

Dietary components with demonstrated effectiveness in decreasing the severity of exercise-induced asthma.

Exercise-induced asthma (EIA) occurs in up to 90% of individuals with asthma and approximately 10% of the general population without asthma. EIA describes a condition in which vigorous physical activity triggers acute airway narrowing with heightened airway reactivity resulting in reductions in forced expiratory volume in 1 second of greater than 10% compared with pre-exercise values. Treatment of EIA almost exclusively involves the use of pharmacological medications.

Exercise-induced bronchoconstriction.

Exercise-induced asthma, or more appropriately, exercise-induced bronchoconstriction (EIB), occurs in 80 to 90% of individuals with asthma and in approximately 11% of the general population without asthma. EIB is characterised by post-exercise airways obstruction resulting in reductions in forced expiratory volume in 1 second (FEV(1)) of greater than 10% compared with pre-exercise values. The mechanism of EIB remains elusive, although both cooling and drying of airways play prominent roles.

Dietary salt alters pulmonary function during exercise in exercise-induced asthmatics.

Epidemiological and experimental studies have suggested that dietary salt may play a role in airway responsiveness. We have previously shown that a low salt diet improves and a high salt diet exacerbates post-exercise pulmonary function in individuals with exercise-induced asthma. The aim of this study was to determine the influence of both elevated and restricted salt diets on pulmonary function during exercise in individuals with exercise-induced asthma.

Dietary chloride as a possible determinant of the severity of exercise-induced asthma.

Dietary sodium chloride (NaCl) has been shown to alter the severity of exercise-induced asthma, but it is not known if the sodium and chloride ions have independent effects in this regard. The hypothesis tested in the present study was that both a low sodium, low chloride diet and a high sodium, low chloride diet would improve post-exercise pulmonary function in subjects with exercise-induced asthma (EIA) compared to a normal NaCl diet (NSD); but that neither of these diets would have an effect on post-exercise pulmonary function in control (non-EIA) subjects. Eight subjects who suffered from EIA and eight subjects who did not (control) took part in a double-blind crossover study.

Elevating dietary salt exacerbates hyperpnea-induced airway obstruction in guinea pigs.

Previous studies have indicated that increased dietary salt consumption worsens postexercise pulmonary function in humans with exercise-induced asthma (EIA). It has been suggested that EIA and hyperpnea-induced airway obstruction (HIAO) in guinea pigs (an animal model of EIA) are mediated by similar mechanisms. Therefore, the purpose of this study was to determine whether altering dietary salt consumption also exacerbated HIAO in guinea pigs.

Gender differences in tolerance to lower body negative pressure.

Background: Previous studies suggest that women have lower tolerance than men do to lower body negative pressure (LBNP). The mechanism(s) responsible has not been determined.

Hypotheses: Women would be less tolerant to presyncopal LBNP than men as determined by several indices of LBNP tolerance.

Dietary salt restriction improves pulmonary function in exercise-induced asthma.

Purpose: Exercise-induced asthma (EIA) occurs in approximately 90% of persons with asthma. The mechanism has not been delineated. Epidemiological studies have suggested that dietary salt may play a role in airway responsiveness.

Hypertension in unilaterally nephrectomized rats induced by single-kidney transfection with angiotensinogen cDNA.

Plasmid expression vectors containing angiotensinogen (ATG) cDNA were complexed to cationic liposomes and injected into the renal artery of unilaterally nephrectomized rats to evaluate the effect of intrarenal ATG cDNA on arterial blood pressure and the renin-angiotensin system. Systolic blood pressures measured by tail cuff on days 12, 16, and 18 after transfection were significantly higher in rats that received ATG cDNA than in control rats that received the lac Z reporter gene. Plasma renin activity and plasma ATG concentration were unchanged.

Moderate sodium restriction does not alter lower body negative pressure tolerance.

Hypothesis: Space travel with exposure to microgravity leads to a significant reduction in orthostatic tolerance on return to Earth, for which countermeasures are only partially successful. The purpose of this study was to examine the effect of moderate dietary sodium restriction on tolerance to LBNP.

Methods: Eight healthy men, age 25.

Cardiovascular effects of the breathhold used in determining pulmonary diffusing capacity.

Background: The single-breath technique for determination of the diffusion capacity of the lung for CO (DlCO) requires a 10-s breathhold at total lung capacity. The assumption has been that this breathhold does not alter the components of DlCO, i.e.

The heart is not necessarily empty at syncope.

Background: Although extensively investigated, the mechanism(s) of post-spaceflight orthostatic intolerance has not been elucidated. Several researchers have proposed that the "trigger" for syncope is an empty ventricle, initiated when a hypercontractile state, possibly due to a sudden surge in epinephrine, causes the walls of the left ventricle to touch leading to a profound sympatho-inhibition and intense vagal stimulation.

Hypothesis: A markedly reduced left ventricular end systolic volume (LVESV) achieved during progressive, presyncopal-limited lower body negative pressure (LBNP) is the trigger for syncope.

Bioelectric impedance as an index of thoracic fluid.

Background: Thoracic electrical impedance (TEI) has been suggested as a means to monitor thoracic fluid changes. It was hypothesized that TEI would correlate significantly with an intrathoracic blood volume (pulmonary capillary blood volume) during postural shifts.

Methods: TEI was compared with pulmonary capillary blood volume (Vc) in six men and six women during postural stress.

Validation of impedance cardiography during lower body negative pressure.

Background: Both echocardiographic and impedance cardiographic techniques have been used individually for the determination of stroke volume (SV) during lower body negative pressure (LBNP). Impedance cardiography has not been validated during LBNP.

Hypothesis: The purpose of this study was to determine both the absolute values for SV and the change in SV for each stage of LBNP using both impedance and echocardiographic techniques during staged LBNP to presyncope.

Physical activity, energy expenditure and fitness: an evolutionary perspective.

The model for human physical activity patterns was established not in gymnasia, athletic fields, or exercise physiology laboratories, but by natural selection acting over eons of evolutionary experience. This paper examines how evolution has determined the potential for contemporary human performance, and advances the experience of recently-studied hunter-gatherers as the best available (although admittedly imperfect) indicator of the physical activity patterns for which our genetically determined biology was originally selected. From the emergence of the genus Homo, over 2 million years ago (MYA), until the agricultural revolution of roughly 10000 years ago our ancestors were hunter-gatherers, so the adaptive pressures inherent in that environmental niche have exerted defining influence on human genetic makeup.

Pulmonary capillary blood volume during lower body negative pressure: effect of gender.

Background: The purpose of this study was to examine the changes in pulmonary capillary blood volume (VC) in men and women during lower body negative pressure (LBNP). Additionally, the components of lung diffusion capacity were measured and evaluated for the effect of gender and LBNP.

Methods: There were 6 men and 6 women who underwent a staged LBNP protocol to -40 mm Hg.

Women have lower tolerance to lower body negative pressure than men.

Studies of the cardiovascular response to lower body negative pressure (LBNP) in men and women have suggested that women may have less tolerance to LBNP than men, although tolerance per se was not determined. To investigate the effect of gender on tolerance to LBNP, 10 men 10 women were subjected to increasing levels of LBNP until presyncopal symptoms developed. The cumulative stress index (CSI) score was determined, as were cardiovascular variables.