Menstrual cycle and oral contraceptive use do not modify postexercise heat loss responses.

It is unknown whether menstrual cycle or oral contraceptive (OC) use influences nonthermal control of postexercise heat loss responses. We evaluated the effect of menstrual cycle and OC use on the activation of heat loss responses during a passive heating protocol performed pre- and postexercise. Women without OC (n = 8) underwent pre- and postexercise passive heating during the early follicular phase (FP) and midluteal phase (LP).

Calorimetric measurement of postexercise net heat loss and residual body heat storage.

Purpose: Previous studies have shown a rapid reduction in postexercise local sweating and blood flow despite elevated core temperatures. However, local heat loss responses do not illustrate how much whole-body heat dissipation is reduced, and core temperature measurements do not accurately represent the magnitude of residual body heat storage. Whole-body evaporative (H(E)) and dry (H(D)) heat loss as well as changes in body heat content (DeltaH(b)) were measured using simultaneous direct whole-body and indirect calorimetry.

Sex-related differences in evaporative heat loss: the importance of metabolic heat production.

We evaluated the hypothesis that different rates of metabolic heat production between sexes, during exercise at the same percentage of maximum oxygen consumption [VO2 max] give proportional differences in evaporative heat loss. Seven males and seven females, exercised at 41.3 +/- 2.

Can supine recovery mitigate the exercise intensity dependent attenuation of post-exercise heat loss responses?

Cutaneous vascular conductance (CVC) and sweat rate are subject to non-thermal baroreflex-mediated attenuation post-exercise. Various recovery modalities have been effective in attenuating these decreases in CVC and sweat rate post-exercise. However, the interaction of recovery posture and preceding exercise intensity on post-exercise thermoregulation remains unresolved.

Physical work capacity in older adults: implications for the aging worker.

Background: In many developed countries, the workforce is rapidly aging. Occupational demands however, have not decreased despite the fact that workers see a decline in physical work capacity with age. The purpose of this review is to examine the physiological adaptations to aging, the impact of aging on performance and the benefits of physical fitness in improving functional work capacity in aging individuals.

Influence of adiposity on cooling efficiency in hyperthermic individuals.

This study evaluated the effect of body adiposity on core cooling rates, as measured by decreases in rectal (T (re)), esophageal (T (es)) and aural canal (T (ac)) temperatures, of individuals rendered hyperthermic by dynamic exercise in the heat. Seventeen male participants were divided into two groups; low body fat (LF, 12.9 +/- 1.

Hyperthermia modifies the nonthermal contribution to postexercise heat loss responses.

Purpose: This study investigated the nonthermoregulatory control of cutaneous vascular conductance (CVC) and sweating during recovery from exercise-induced hyperthermia as well as possible sex-related differences in these responses. Two hypotheses were tested in this study: 1) active and passive recovery would be more effective in attenuating the fall in mean arterial pressure (MAP) than inactive recovery, but CVC and sweat rate responses would be similar between all recovery modes; and 2) the magnitude of the change in postexercise heat loss and hemodynamic responses between recovery modes would be similar between sexes.

Methods: Nine males and nine females were rendered hyperthermic (esophageal temperature = 39.

Human heat balance during postexercise recovery: separating metabolic and nonthermal effects.

Previous studies report greater postexercise heat loss responses during active recovery relative to inactive recovery despite similar core temperatures between conditions. Differences have been ascribed to nonthermal factors influencing heat loss response control since elevations in metabolism during active recovery are assumed to be insufficient to change core temperature and modify heat loss responses. However, from a heat balance perspective, different rates of total heat loss with corresponding rates of metabolism are possible at any core temperature.

Use of target controlled infusion to derive age and gender covariates for propofol clearance.

Background And Objective: Attempts to describe the variability of propofol pharmacokinetics in adults and to derive population covariates have been sparse and limited mainly to experiments based on bolus doses or infusions in healthy volunteers. This study aimed to identify age and gender covariates for propofol when given as an infusion in anaesthetized patients.

Study Design And Setting: One hundred and thirteen patients (American Society of Anesthesiologists class I or II and aged 14-92 years) were anaesthetized for elective surgical procedures with propofol using a target controlled infusion (TCI) system and with alfentanil as a baseline analgesic infusion.

Effects of aerobic training, resistance training, or both on glycemic control in type 2 diabetes: a randomized trial.

Background: Previous trials have evaluated the effects of aerobic training alone and of resistance training alone on glycemic control in type 2 diabetes, as assessed by hemoglobin A1c values. However, none could assess incremental effects of combined aerobic and resistance training compared with either type of exercise alone.

Objective: To determine the effects of aerobic training alone, resistance training alone, and combined exercise training on hemoglobin A1c values in patients with type 2 diabetes.

Postexercise heat loss and hemodynamic responses during head-down tilt are similar between genders.

Purpose: We evaluated the hypothesis that during recovery from dynamic exercise in the 15 degrees head-down tilt (HDT) position, the attenuation of the fall in mean arterial pressure (MAP), cutaneous vascular conductance (CVC), and sweat rate, and the augmentation of the rate of esophageal temperature (T(es)) decay relative to the upright seated (URS) posture, would be different between males and females.

Methods: Fourteen subjects (seven males, seven females) performed two experimental protocols: 1) 15 min of cycle ergometry at 75% VO2peak and then 60 min of recovery in the URS posture; or 2) 15 min of cycle ergometry at 75% VO2peak and then 60 min of recovery in the 15 degrees HDT position. Mean skin temperature, Tes, CVC, sweat rate, cardiac output (CO), stroke volume (SV), heart rate (HR), total peripheral resistance (TPR), and MAP were recorded at baseline; end of exercise; 2 min, 5 min, 8 min, 12 min, 15 min, and 20 min after exercise; and every 5 min until the end of recovery (60 min).

Evidence of a greater onset threshold for sweating in females following intense exercise.

We evaluated the hypothesis that females would show a greater postexercise hypotension and concurrently a greater increase in the onset threshold for sweating. Fourteen subjects (7 males and 7 females) of similar age, body composition, and fitness status participated in the study. Esophageal temperature was monitored as an index of core temperature while sweat rate was measured by using a ventilated capsule placed on the upper back.

Fueling shivering thermogenesis during passive hypothermic recovery.

In humans, the relative importance of oxidative fuels for sustaining shivering during passive hypothermic recovery or rewarming is still unclear. The main goals of this study were 1) to quantify the respective contributions of lipids and carbohydrates (CHO) during passive rewarming and 2) to determine the effects of precooling exercise on the pattern of fuel utilization. With indirect calorimetry methodologies, changes in fuel metabolism were quantified in nonacclimatized adult men shivering to rewarm from moderate hypothermia (core temperature approximately 34.

Disturbance of thermal homeostasis following dynamic exercise.

Recovery from dynamic exercise results in significant perturbations of thermoregulatory control. These perturbations evoke a prolonged elevation in core body temperature and a concomitant decrease in sweating, skin blood flow, and skin temperature to pre-exercise baseline values within the early stages of recovery. Cutaneous vasodilation and sweating are critical responses necessary for effective thermoregulation during heat stress in humans.

Simulator programs for new nurses' orientation: a retention strategy.

The phenomenon of role transition for new nurses has been a topic of research and concern for practicing nurses, educators, and administrators for many years. This transition has an impact on the job retention of new nurses. Stress, lack of confidence, and unmet expectations have been found to influence patient safety and outcomes.

Estimating changes in mean body temperature for humans during exercise using core and skin temperatures is inaccurate even with a correction factor.

Changes in mean body temperature (DeltaT(b)) estimated by the traditional two-compartment model of "core" and "shell" temperatures and an adjusted two-compartment model incorporating a correction factor were compared with values derived by whole body calorimetry. Sixty participants (31 men, 29 women) cycled at 40% of peak O(2) consumption for 60 or 90 min in the Snellen calorimeter at 24 or 30 degrees C. The core compartment was represented by esophageal, rectal (T(re)), and aural canal temperature, and the shell compartment was represented by a 12-point mean skin temperature (T(sk)).

Sex differences in postexercise esophageal and muscle tissue temperature response.

Factors associated with blood pressure regulation during recovery from exercise dramatically influence core temperature regulation. However, it is unknown whether sex-related differences in postexercise hemodynamics affect core and muscle temperature response. Sixteen participants (8 males, 8 females) completed an incremental isotonic test on a Kin-Com isokinetic apparatus to determine their activity-specific peak oxygen consumption during bilateral knee extensions (Vo(2)(sp)).

Thermoregulatory control following dynamic exercise.

Post-exercise thermoregulatory control in humans has received limited attention. In the post-exercise period skin blood flow and sweating return to pre-exercise levels despite a persistent elevation in esophageal temperature, suggesting an alteration in thermoregulatory control. The esophageal temperature response post-exercise appears to be correlated to the marked cardiovascular changes that occur after dynamic exercise.

Sedation for endoscopy.

A review of the recent literature reveals an increasing published opinion in favour of unsedated endoscopy. However, recent studies show that the majority of US patients are unwilling or unable to tolerate this. In order for there to be a shift towards unsedated endoscopy, physicians will have to change patients' expectations.

Feedback control of anaesthesia.

Feedback control of anaesthesia can improve the quality of patient care while reducing the administration and cost of anaesthetic drugs. Systems have been available for several years to control blood pressure and neuromuscular blockade. Control of anaesthetic depth has been reported using the median frequency of the electroencephalogram.

The contribution of remifentanil to middle latency auditory evoked potentials during induction of propofol anesthesia.

There is a debate regarding whether opioids, as a component of general anesthesia, are adequately reflected in the assessment of anesthesia based on derivatives of the electroencephalogram. To test the hypothesis of a possible quantitative contribution of remifentanil on middle latency auditory evoked potentials, we studied its interaction with propofol anesthesia in 45 unpremedicated male patients undergoing elective lower limb orthopedic surgery. They were allocated randomly to three groups.

Attention deficit hyperactivity disorder: the current debate and neglected dimensions.

The aim of this article is to identify and highlight the issues facing children, young people and families experiencing Attention Deficit Hyperactivity Disorder (ADHD) in an United Kingdom context. In presenting these issues it is hoped that wider discussion and awareness of the challenges of this condition may have an effect on the planning and delivery of services within the UK. We seek to highlight that an overreliance on a medical perspective has the effect of neglecting the wider context of the rights of the child and the needs of the family.

The Snellen human calorimeter revisited, re-engineered and upgraded: design and performance characteristics.

The measurement of whole body heat loss in humans and the performance characteristics of a modified Snellen whole body air calorimeter are described. Modifications included the location of the calorimeter in a pressurized room, control of operating temperature over a range of - 15 to + 35 degrees C, control of ambient relative humidity over a range of 20-65%, incorporation of an air mass flow measuring system to provide real time measurement of air mass flow through the calorimeter, incorporation of a constant load 'eddy current' resistance ergometer and an open circuit, expired gas analysis calorimetry system. The performance of the calorimeter is a function of the sensitivity, precision, accuracy and response time characteristics of the fundamental measurement systems including: air mass flow; thermometry and hygrometry.

A three-compartment thermometry model for the improved estimation of changes in body heat content.

The aim of this study was to use whole body calorimetry to directly measure the change in body heat content (DeltaH(b)) during steady-state exercise and compare these values with those estimated using thermometry. The thermometry models tested were the traditional two-compartment model of "core" and "shell" temperatures, and a three-compartment model of "core," "muscle," and "shell" temperatures; with individual compartments within each model weighted for their relative influence upon DeltaH(b) by coefficients subject to a nonnegative and a sum-to-one constraint. Fifty-two participants performed 90 min of moderate-intensity exercise (40% of Vo(2 peak)) on a cycle ergometer in the Snellen air calorimeter, at regulated air temperatures of 24 degrees C or 30 degrees C and a relative humidity of either 30% or 60%.