The decimal reduction times of Streptococcus faecium, Listeria monocytogenes, Salmonella enteritidis, and Aeromonas hydrophila corresponding to heat treatment at 62 degrees C were 7.1, 0.34, 0.024, and 0.0096 min, and those corresponding to manosonication treatment (40 degrees C, 200 kPa, 117 microm) were 4.0, 1.5, 0.86, and 0.90 min, respectively. ...

Heat shock proteins (HSP) are a characteristic set of highly conserved proteins that are synthesized shortly after the organism is exposed to external stress, including physical activity. HSP help to maintain cellular homeostasis and protein conformation, reactivate denatured or malformed proteins, and provide "housekeeping," translocase, and chaperone functions. Some of ...

This study examined the effects of beverage composition on the voluntary drinking pattern, body fluid balance, and thermoregulation of heat-acclimatized trained boys exercising intermittently in outdoor conditions (wet bulb globe temperature 30.4 +/- 1.0 degreesC). Twelve boys (age 13.4 +/- 0.4 yr) performed two 3-h sessions, each consisting of four ...

This study examined the effects of 3 days of estrogen supplementation (ES) on thermoregulation during exercise in premenopausal (20-39 yr) adult women during the follicular phase of the menstrual cycle. Subjects (11 control, 10 experimental) performed upright cycle ergometer exercise at 60% of maximal O2 consumption in a neutral environment ...

OBJECTIVE: To compare two techniques of irrigation flow control with regard to risk of absorption of uterine irrigation fluid during operative hysteroscopy. METHODS: We compared two techniques of uterine irrigation fluid outflow management-passive gravity outflow and direct connection of the outflow to wall suction-in a randomized controlled trial involving 40 ...

Fasting induces nocturnal hypothermia in pigeons. Slow-wave sleep (SWS) and paradoxical sleep (PS) are associated with reduced heat production in pigeons. The possibility that fasting-induced nocturnal hypothermia is related to increased SWS and PS was examined by comparing body temperature (Tb) and vigilance states when pigeons were fed and fasted. ...

Titanium-zirconium based alloys containing a small amount of niobium were investigated in order to evaluate their possible use as biomedical materials. Zirconium, which belongs to the IVa group, is known to have good corrosion resistance and biocompatibility similar to titanium. As the titanium-zirconium system shows a complete solid solution, a ...

A physiological strain index (PSI), based on rectal temperature (Tre) and heart rate (HR), was recently suggested for evaluating heat stress. The purpose of this study was to evaluate the PSI for different combinations of hydration level and exercise intensity. This index was applied to two databases. The first database ...

A physiological strain index (PSI), based on rectal temperature (Tre) and heart rate (HR), capable of indicating heat strain online and analyzing existing databases, has been developed. The index rates the physiological strain on a universal scale of 0-10. It was assumed that the maximal Tre and HR rise during ...

BACKGROUND: Vena cava diameter (VCD) measurement is an accepted method to evaluate hydration status in patients on hemodialysis. Bioelectrical impedance analysis (BIA) is a less laborious method to assess hydration variables and more suitable for routine patient care. However, BIA has not yet been validated in dialysis patients. We investigated ...

To elucidate the role of increased plasma osmolality (Posmol), which occurs during exercise in the regulation of cutaneous vasodilation (CVD) during exercise, we determined the relationship between the change in esophageal temperature (DeltaTes) required to elicit CVD (DeltaTes threshold for CVD) and Posmol during light and moderate exercise (30 and ...

Because metabolic heat production is proportional to the amount of work performed, the differences in core body temperature (Tcore) of humans exercising at similar absolute exercise intensities are due to differences in their efficiency of heat dissipation. The purpose of this paper is to delineate the effects of training status, ...

The restoration of body fluid balance following dehydration induced by exercise will occur through regulatory responses which stimulate ingestion of water and sodium ions. A number of different afferent signalling systems are necessary to generate appropriate thirst or sodium appetite. The primary sensory information of naturally occurring thirst is derived ...

Three exercise-related heat illnesses are described in the literature -- heat cramps, heat exhaustion or heat syncope, and heat stroke. Of these, only exercise-induced heat stroke, which occurs infrequently, is definitely a heat illness caused by an increased rate of heat production unmatched by adequate heat loss causing progressive heat ...

During strenuous exercise the body's heat production may exceed 1000 W. Some of the heat produced is stored, raising body core temperature by a few degrees. Rises in body temperature are sensed by central and skin thermoreceptors and this sensory information is processed by the hypothalamus to trigger appropriate effector ...

More than 200 years ago, in 1768, Lind in his monograph: "An assay on diseases incidental to Europeans in hot climate" pointed out that habituation to hot climates reduced the danger to health. Two centuries later, Lind and Bass in a classical study which was carried out under hot/dry climatic ...

The initial conditioning of the inhaled gases occurs in the upper respiratory tract. The conditioned gases are at approximately 32 degrees C and more than 95% relative humidity as they enter the lower respiratory tract. This level of heat and humidity will preserve the body's defense mechanisms. When the upper ...

The purpose of the present study was to determine the separate and combined effects of a short-term aerobic training program and hypohydration on tolerance during light exercise while wearing nuclear, biological, and chemical protective clothing in the heat (40 degrees C, 30% relative humidity). Males of moderate fitness [< 50 ...

The construction and performance of a 5.4 m3 combined direct and indirect calorimeter for human subjects is described. The calorimeter was constructed for studies on human subjects primarily undergoing fast alterations in heat production and heat losses, e.g. after a meal or during physical exercise. A heat sink and a ...

The short papers collected together here provide a concise but comprehensive summary of the key issues relating to exercise in the heat. This Conference was the first major international meeting devoted solely to the physiological challenge of extreme exercise in the heat and the strategies that can be implemented to ...

This study examined the efficacy of glycerol and water hyperhydration (1 h before exercise) on tolerance and cardiovascular strain during uncompensable exercise-heat stress. The approach was to determine whether 1-h preexercise hyperhydration (29.1 ml H2O/kg lean body mass with or without 1.2 g/kg lean body mass of glycerol) provided a ...

This study examined the effects of hyperhydration, exercise-induced dehydration, and oral fluid replacement on physiological strain of horses during exercise-heat stress. On three occasions, six horses completed a 90-min exercise protocol (50% maximal O2 uptake, 34.5 degrees C, 48% relative humidity) divided into two 45-min periods (exercise I and exercise ...

More is known about the time course for the acquisition of human heat acclimation during exercise than its decay or loss. Pioneering research in the 1940s led to our early understanding of the heat acclimation process and its subsequent decay with further knowledge concerning the associated physiological mechanisms in later ...

Selye (1936) described how organisms react to various external stimuli (i.e., stressors). These reactions generally follow a programmed series of events and help the organism adapt to the imposed stress. The heat shock response is a common cellular reaction to external stressors, including physical activity. A characteristic set of proteins ...

The combination of heat stress, dehydration, and exercise imposes perhaps the most-severe physiological challenge for the human body short of disease or serious bleeding. Exercise in the heat requires the body to attempt to cope simultaneously with competing demands for cardiovascular homeostasis, thermoregulatory control, and maintenance of muscle energetics. When ...

Exercise in the heat results in major alterations in circulatory, thermoregulatory and metabolic function. Hyperthermia appears to be the critical determinant of exercise performance in the heat. Thus, strategies that minimise the rise in core temperature during exercise in the heat are likely to contribute to enhanced performance. These include ...

During endurance exercise in the heat athletes lose 1-21/h of fluid due to thermoregulatory sweating. The ensuing dehydration is accompanied by higher and faster increases in core temperature, which per se can cause fatigue. The main cardiovascular consequences of combined dehydration and hyperthermia [1 degree C higher core temperature and ...

During exercise in the heat, sweat output often exceeds water intake which results in a body water deficit (hypohydration) and electrolyte losses. Daily water losses can be substantial and persons need to emphasize drinking during exercise as well as at mealtime. Aerobic exercise tasks are likely to be adversely affected ...

Repeated exposures to exercise and heat produce acclimatization, changes in physiological function by which the tolerance to heat stress is improved. The main issues to be discussed are the possible mechanisms for the increase in plasma volume, the increase in sweating rate and the endocrine responses to exercise with acclimation ...

The purpose of this study was to test the hypothesis that a reduction in resting rectal temperature (Tre) is partially responsible for the attenuation in the rise of core temperature during the heat exposure following acclimation to humid heat. Nine male volunteers completed 7 days of acclimation, performing 2 h ...

When the oxygen binding isotherms of human, bovine and fallow deer (Dama-Dama) hemoglobins are measured at different temperatures either by optical or calorimetric techniques, analyses according to the Adair's formalism show that at least one of the intermediate steps of ligation has a positive enthalpy change, i.e., absorbs rather than ...

The purpose of the present study was to determine the separate and combined effects of aerobic fitness, short-term heat acclimation, and hypohydration on tolerance during light exercise while wearing nuclear, biological, and chemical protective clothing in the heat (40 degrees C, 30% relative humidity). Men who were moderately fit [(MF); ...

In the horse, sweat is produced by apocrine glands which are present over most haired and nonhaired skin. Although sweat secretion is initiated under a number of circumstances, the central drive for sweating in response to a thermal stimulus is the primary mechanism for its production. Sweating is an essential ...

We have previously documented the regional distribution of 70-kDa heat shock protein (HSP70) in brains of rats made hyperthermic by brief exposure to high-powered microwaves (HPM; 2.06 GHz). We now compare HSP70 expression induced by HPM exposure to that induced by exertional and/or environmental heat stress. Rats were chronically implanted ...

The large metabolic heat load generated as a consequence of muscular work requires activation of thermoregulatory mechanisms in order to prevent an excessive and potentially dangerous rise in body temperature during exercise. Although the horse has highly efficient heat dissipatory mechanisms, there are a number of circumstances in which the ...

BACKGROUND: Clinical reports associate the use of epidural anesthesia with an increase in core temperature in women in labor. We tested the hypothesis that epidural anesthesia alters thermoregulatory responses to hyperthermia in human volunteers. METHODS: Each of four volunteers were studied on two days: Control and Anesthesia. On the Control ...

Seven endurance-trained and heat-nonacclimated men (Mean+/-SEM: 20+/-1 yr; VO2max = 67+/-2 ml x kg(-1) x min(-1)) ran in two environments (M: 23 degrees C, H: 38 degrees C; 7 days apart) at two absolute training-intensity velocities (S1: 240 m x min(-1); followed by S2: 270 m x min(-1); 10 min ...

Improved cardiac post-ischemic recovery after whole-body hyperthermia is correlated with an increased expression of the heat shock proteins (hsps). The inducible hsp70 (hsp70i) has a known cardioprotective effect against ischemia/reperfusion injury. Here, we studied whether other hsps are also involved in cardioprotection. Using rat heart-derived H9c2 myocytes, we observed that ...

Two experiments examined the influences of endurance training and heat acclimation on ratings of perceived exertion (RPE) and thermal discomfort (RTD) during exercise in the heat while wearing two types of clothing. In experiment 1, young men underwent 8 weeks of physical training [60-80% of maximal aerobic power (VO2max) for ...

Twelve 10- to 12-year-old healthy boys performed six 70-min intermittent exercise sessions (three 20-min cycling bouts at 50% VO2max with 5 min rest in between) over a 2-week period at 35 +/- 1 degrees C, 50 +/- 5% or 60 +/- 5% relative humidity. Subjects drank grape-flavored solution with 6% ...

Multiple heterogeneous groups of subjects (both sexes and a wide range of maximal oxygen uptake VO2max, body mass, body surface area (AD),% body fat, and AD/mass coefficient) exercised on a cycle ergometer at a relative (%VO2max, REL) or an absolute (60 W) exercise intensity in a cool (CO 21 degrees ...

This study determined the effects of exercise intensity on the physiologic (thermal and cardiovascular) strain induced from hypohydration during heat stress. We hypothesized that the added thermal and cardiovascular strain induced by hypohydration would be greater during high intensity than low intensity exercise. Nine heat-acclimated men completed a matrix of ...

Pacific whiting surimi gels heated slowly in a water bath exhibited poor gel quality, while the ohmically heated gels without holding at 55 degrees C showed more than a twofold increase in shear stress and shear strain over conventionally heated gels. Degradation of myosin and actin was minimized by ohmic ...

The purpose of the present study was to investigate the influence of hypohydration and fluid replacement on tolerance to an uncompensable heat stress. Eight healthy young males completed a matrix of six trials in an environmental chamber, set at 40 degrees C and 30% relative humidity, while wearing nuclear, biological, ...

To assess the effect of branched-chain amino acids (BCAA) supplementation on endurance performance in the heat, six women and seven men participated in two trials of rest in the heat (Ta = 34.4 +/- 1.8 degrees C; rh = 39 +/- 14%), followed by 40% VO2peak exercise to exhaustion. Subjects ...

The purpose of this study was to test the validity of a multiple frequency bioimpedance spectroscopy (BIS) technique that estimates extracellular fluid volume (ECV), intracellular fluid volume (ICV), and total body water (TBW). Thirteen healthy males (mean +/- SD: age, 23 +/- 3 yr; body mass, 80.6 +/- 14.7 kg) ...

Rate and ionic composition of sweat fluid losses and partitioning of evaporative heat loss into respiratory and cutaneous components were determined in six horses during three 15-km phases of exercise at approximately 40% of maximal O2 uptake. Pattern of change in sweat rate (SR) and composition was similar during each ...

Six healthy men completed three 1-hr bouts of treadmill walk-jogging at low (L; 42 +/- 3.9% VO2max), moderate (M; 55 +/- 5.6%), and high (H; 67 +/- 4.5%) exercise intensity in order to determine whether moderate physical activity affects dietary protein needs. Both sweat rate and sweat urea N loss ...

This study examined the effects of hyperhydration on thermoregulatory responses during compensable exercise-heat stress. The general approach was to determine whether 1-h preexercise hyperhydration [29. 1 ml/kg lean body mass; with or without glycerol (1.2 g/kg lean body mass)] would improve sweating responses and reduce core temperature during exercise. During ...

Maintenance of fluid balance is a major concern for all athletes competing in events held in hot climates. This paper reviews recent work relating to optimisation of fluid replacement after sweat loss induced by exercising in the heat. Data are taken from studies undertaken in our laboratory. Issues investigated were ...