Can gender differences during exercise-heat stress be assessed by the physiological strain index?
A physiological strain index (PSI) based on rectal temperature (Tre) and heart rate (HR) was recently suggested to evaluate exercise-heat stress. The purpose of this study was to evaluate PSI for gender differences under various combinations of exercise intensity and climate. Two groups of eight men each were formed according to maximal rate of O2 consumption (VO2 max). The first group of men (M) was matched to a group of nine women (W) with similar (P > 0.001) VO2 max (46.1 +/- 2.0 and 43.6 +/- 2.9 ml. kg-1. min-1, respectively). The second group of men (MF) was significantly (P < 0. 001) more fit than M or W with VO2 max of 59.1 +/- 1.8 ml. kg-1. min-1. Subjects completed a matrix of nine experimental combinations consisting of three different exercise intensities for 60 min [low, moderate, and high (300, 500, and 650 W, respectively)] each at three climates (comfortable, hot wet, and hot dry [20 degrees C 50% relative humidity (RH), 35 degrees C 70% RH, and 40 degrees C 35% RH, respectively]). No significant differences (P > 0.05) were found between matched genders (M and W) at the same exposure for sweat rate, relative VO2 max (%VO2 max), and PSI. However, MF had significantly (P < 0.05) lower strain than M and W as reflected by %VO2 max and PSI. In summary, PSI applicability was extended for exercise-heat stress and gender. This index continues to show potential for wide acceptance and application. (+info
Remembrance of things past and concerns for the future.
Stanley G. Schultz received the seventh annual Arthur C. Guyton Physiology Teacher of the Year Award. The following is a speech he delivered as he was presented the award at Experimental Biology '99 in Washington, DC, in April 1999. (+info
Learning physiology through service.
A service-learning component has been successfully incorporated into an introductory physiology course at Wheaton College. In addition to regular course work, each of the 24 students spent 12 hours shadowing and assisting staff at Sturdy Memorial Hospital, Attleboro, MA, with 4 hours in the emergency room and 8 hours in two other departments. Every student kept a log of his or her observations, reactions, and learning in the field and wrote a paper on a pathophysiological condition encountered in the hospital. To compare and contrast the real hospital experience with a fictional one, the students also studied patients from the television show ER. Each week in lab, two students showed a short videotape of one particular patient and discussed the diagnosis, symptoms, treatments, and surgical procedures involved. Questionnaire evaluations indicated that this program is effective in helping students learn more physiology and exposing them to community service. Health workers and patients also agreed that providing social support to patients while shadowing and assisting hospital staff was a valuable service. (+info
Predictors of success in undergraduate human physiology.
This study tested the hypothesis that measurable attributes in students' backgrounds are related to their successful completion of an undergraduate human physiology course. Demographic, general academic performance, and science achievement data were obtained from student records for students enrolled during the 1995-1996 academic year, and additional demographic data were obtained from students enrolled during the 1996-1998 academic years. A hierarchical logistic regression analysis explored the relationship fo these variables to the percentage of students passing the human physiology course. Predicted passing versus failing showed a sensitivity of 85.5% and specificity of 69.7%. Two independent validations of the logistical regression equation correctly predicted the performance of subsequent groups of students 75.9% and 77.6% of the time. (+info
Undergraduate students' misconceptions about respiratory physiology.
Approximately 700 undergraduates studying physiology at community colleges, a liberal arts college, and universities were surveyed to determine the prevalence of our misconceptions about respiratory phenomena. A misconception about the changes in breathing frequency and tidal volume (physiological variables whose changes can be directly sensed) that result in increased minute ventilation was found to be present in this population with comparable prevalence (approximately 60%) to that seen in a previous study. Three other misconceptions involving phenomena that cannot be experienced directly and therefore were most likely learned in some educational setting were found to be of varying prevalence. Nearly 90% of the students exhibited a misconception about the relationship between arterial oxygen partial pressure and hemoglobin saturation. Sixty-six percent of the students believed that increasing alveolar oxygen partial pressure leads to a decrease in alveolar carbon dioxide partial pressure. Nearly 33% of the population misunderstood the relationship between metabolism and ventilation. The possible origins of these respiratory misconceptions are discussed and suggestions for how to prevent and/or remediate them are proposed. (+info
Basis for presentation of acid-base in two dimensions.
Buffering of "metabolic" acid in tissues other than blood correlates closely with a change in extracellular bicarbonate concentration rather than with a change in extracellular pH. Of particular importance is the evidence for an absence of relation to change in pH. Questions are raised with respect to buffering mechanism, but simplification is offered for diagnosis. A clearer focus can be given to the guidepost changes in PCO2 and bicarbonate concentration. Basic relationships of buffering in the whole body are reviewed, and a modified diagnostic rationale is offered, based on a two-rather than a three-dimensional analysis. (+info
Challenges of teaching physiology in a PBL school.
A problem-based learning (PBL) curriculum was introduced at McMaster University more than three decades ago. Not many schools have adopted the system despite its distinct advantages. The present paper examines the challenges of teaching physiology in a PBL curriculum and gleans through the literature supporting PBL. It appears that one of the reasons why PBL is not becoming readily acceptable is the lack of concrete reports evaluating the curricular outcomes. The suggestion (R.E. Thomas. Med Educ. 31:320-329, 1997) to standardize and internationalize all components of validated PBL curricula is quite valid. A database needs to be generated that can be easily accessed by traditional institutions to see the rationality and easy implementation of the PBL curriculum. (+info
Refresher course for teaching cardiovascular physiology.
This report presents highlights of a refresher course presented at Experimental Biology '99 on Saturday, April 17, 1999, in Washington, District of Columbia. (+info