SARS-CoV-2 control on a large urban college campus without mass testing.

OBJECTIVE: A small percentage of universities and colleges conducted mass SARS-CoV-2 testing. However, universal testing is resource-intensive, strains national testing capacity, and false negative tests can encourage unsafe behaviors. PARTICIPANTS: A large urban university campus. METHODS: Virus control centered on three pillars: mitigation, containment, and communication, with testing of symptomatic and a random subset of asymptomatic students. RESULTS: Random surveillance testing demonstrated a prevalence among asymptomatic students of 0.4% throughout the term. There were two surges in cases that were contained by enhanced mitigation and communication combined with targeted testing. Cumulative cases totaled 445 for the term, most resulting from unsafe undergraduate student behavior and among students living off-campus. A case rate of 232/10,000 undergraduates equaled or surpassed several peer institutions that conducted mass testing. CONCLUSIONS: An emphasis on behavioral mitigation and communication can control virus transmission on a large urban campus combined with a limited and targeted testing strategy.

Population-based hospitalization burden estimates for respiratory viruses, 2015-2019.

BACKGROUND: Acute respiratory infections (ARIs) result in millions of illnesses and hundreds of thousands of hospitalizations annually in the United States. The responsible viruses include influenza, parainfluenza, human metapneumovirus, coronaviruses, respiratory syncytial virus (RSV), and human rhinoviruses. This study estimated the population-based hospitalization burden of those respiratory viruses (RVs) over 4 years, from July 1, 2015 to June 30, 2019, among adults ≥18 years of age for Allegheny County (Pittsburgh), Pennsylvania. METHODS: We used population-based statewide hospital discharge data, health system electronic medical record (EMR) data for RV tests, census data, and a published method to calculate burden. RESULTS: Among 26,211 eligible RV tests, 67.6% were negative for any virus. The viruses detected were rhinovirus/enterovirus (2552; 30.1%), influenza A (2,299; 27.1%), RSV (1082; 12.7%), human metapneumovirus (832; 9.8%), parainfluenza (601; 7.1%), influenza B (565; 6.7%), non-SARS-CoV-2 coronavirus (420; 4.9% 1.5 years of data available), and adenovirus (136; 1.6%). Most tests were among female (58%) and White (71%) patients with 60% of patients ≥65 years, 24% 50-64 years, and 16% 18-49 years. The annual burden ranged from 137-174/100,000 population for rhinovirus/enterovirus; 99-182/100,000 for influenza A; and 56-81/100,000 for RSV. Among adults <65 years, rhinovirus/enterovirus hospitalization burden was higher than influenza A; whereas the reverse was true for adults ≥65 years. RV hospitalization burden increased with increasing age. CONCLUSIONS: These virus-specific ARI population-based hospital burden estimates showed significant non-influenza burden. These estimates can serve as the basis for several areas of research that are essential for setting funding priorities and guiding public health policy.

Emergency Department Communication in Persons Living With Dementia and Care Partners: A Scoping Review.

OBJECTIVES: To synthesize published research exploring emergency department (ED) communication strategies and decision-making with persons living with dementia (PLWD) and their care partners as the basis for a multistakeholder consensus conference to prioritize future research. DESIGN: Systematic scoping review. SETTINGS AND PARTICIPANTS: PLWD and their care partners in the ED setting. METHODS: Informed by 2 Patient-Intervention-Comparison-Outcome (PICO) questions, we conducted systematic electronic searches of medical research databases for relevant publications following standardized methodological guidelines. The results were presented to interdisciplinary stakeholders, including dementia researchers, clinicians, PLWD, care partners, and advocacy organizations. The PICO questions included: How does communication differ for PLWD compared with persons without dementia? Are there specific communication strategies that improve the outcomes of ED care? Future research areas were prioritized. RESULTS: From 5451 studies identified for PICO-1, 21 were abstracted. From 2687 studies identified for PICO-2, 3 were abstracted. None of the included studies directly evaluated communication differences between PLWD and other populations, nor the effectiveness of specific communication strategies. General themes emerging from the scoping review included perceptions by PLWD/care partners of rushed ED communication, often exacerbated by inconsistent messages between providers. Care partners consistently reported limited engagement in medical decision-making. In order, the research priorities identified included: (1) Barriers/facilitators of effective communication; (2) valid outcome measures of effective communication; (3) best practices for care partner engagement; (4) defining how individual-, provider-, and system-level factors influence communication; and (5) understanding how each member of ED team can ensure high-quality communication. CONCLUSIONS AND IMPLICATIONS: Research exploring ED communication with PLWD is sparse and does not directly evaluate specific communication strategies. Defining barriers and facilitators of effective communication was the highest-ranked research priority, followed by validating outcome measures associated with improved information exchange.

Respiratory Viral Infections and Infection Prevention Practices Among Women With Acute Respiratory Illness During Delivery Hospitalizations During the 2019-2020 Influenza Season.

BACKGROUND: We conducted a cross-sectional study of pregnant women with acute respiratory illness during delivery hospitalizations during influenza season to describe clinical testing for respiratory viruses and infection prevention practices. METHODS: Women had nasal swabs tested for influenza and other respiratory viruses. Among 91 enrolled women, 22 (24%) had clinical testing for influenza. RESULTS: Based on clinical and study testing combined, 41 of 91 (45%) women had samples positive for respiratory viruses. The most common virus was influenza (17 of 91, 19%); 53% (9 of 17) of influenza virus infections were identified through study testing alone. Only 16% of women were on droplet precautions. CONCLUSIONS: Peripartum respiratory infections may be underrecognized.

Performance of SARS-CoV-2 antigen testing in symptomatic and asymptomatic adults: a single-center evaluation.

BACKGROUND: Antigen testing offers rapid and inexpensive testing for SARS-CoV-2 but concerns regarding performance, especially sensitivity, remain. Limited data exists for use of antigen testing in asymptomatic patients; thus, performance and reliability of antigen testing remains unclear. METHODS: 148 symptomatic and 144 asymptomatic adults were included. A nasal swab was collected for testing by Quidel Sofia SARS IFA (Sofia) as point of care. A nasopharyngeal swab was also collected and transported to the laboratory for testing by Cepheid Xpert Xpress SARS-CoV-2/Flu/RSV RT-PCR (Cepheid). RESULTS: Overall, Sofia had good agreement with Cepheid (> 95%) in adults, however was less sensitive. Sofia had a sensitivity of 87.8% and 33.3% for symptomatic and asymptomatic patients, respectively. Among symptomatic patients, testing > 5 days post symptom onset resulted in lower sensitivity (82%) when compared with testing within 5 days of symptom onset (90%). Of the four Sofia false-negative results in the asymptomatic cohort, 50% went on to develop COVID-19 disease within 5 days of testing. Specificity in both symptomatic and asymptomatic cohorts was 100%. CONCLUSIONS: Sofia has acceptable performance in symptomatic adults when tested < 5 days of symptom onset. Caution should be taken when testing patients with ≥ 5 days of symptoms. The combination of low prevalence and reduced sensitivity results in relatively poor performance of in asymptomatic patients. NAAT-based diagnostic assays should be considered in when antigen testing is unreliable, particularly in symptomatic patients with > 5 days of symptom onset and asymptomatic patients.

Care transitions and social needs: A Geriatric Emergency care Applied Research (GEAR) Network scoping review and consensus statement.

OBJECTIVES: Individual-level social needs have been shown to substantially impact emergency department (ED) care transitions of older adults. The Geriatric Emergency care Applied Research (GEAR) Network aimed to identify care transition interventions, particularly addressing social needs, and prioritize future research questions. METHODS: GEAR engaged 49 interdisciplinary stakeholders, derived clinical questions, and conducted searches of electronic databases to identify ED discharge care transition interventions in older adult populations. Informed by the Protocol for Responding to and Assessing Patients' Assets, Risks, and Experiences (PRAPARE) framework, data extraction and synthesis of included studies included the degree that intervention components addressed social needs and their association with patient outcomes. GEAR convened a consensus conference to identify topics of highest priority for future care transitions research. RESULTS: Our search identified 248 unique articles addressing care transition interventions in older adult populations. Of these, 17 individual care transition intervention studies were included in the current literature synthesis. Overall, common care transition interventions included coordination efforts, comprehensive geriatric assessments, discharge planning, and telephone or in-person follow-up. Fourteen of the 17 care transition intervention studies in older adults specifically addressed at least one social need within the PRAPARE framework, most commonly related to access to food, medicine, or health care. No care transition intervention addressing social needs in older adult populations consistently reduced subsequent health care utilization or other patient-centered outcomes. GEAR stakeholders identified that determining optimal outcome measures for ED-home transition interventions was the highest priority area for future care transitions research. CONCLUSIONS: ED care transition intervention studies in older adults frequently address at least one social need component and exhibit variation in the degree of success on a wide array of health care utilization outcomes.

Cardiovascular Effects of Compression Garments During Uncompensable Heat Stress.

ABSTRACT: Bautz, J, Hostler, D, Khorana, P, and Suyama, J. Cardiovascular effects of compression garments during uncompensable heat stress. J Strength Cond Res 35(4): 1058-1065, 2021-This study examined the potential hemodynamic benefits of wearing lower extremity compression garments (CGs) beneath thermal protective clothing (TPC) worn by wildland firefighters, while exercising in a heated environment. Using in a counterbalanced design, 10 male subjects ([mean ± SD] age 27 ± 6 years, height 1.78 ± 0.09 m, body mass 74.8 ± 7.0 kg, body fat 10.6 ± 4.2%, and V̇o2max 57.8 ± 9.3 ml·kg-1·min-1) completed control (no CG) and experimental (CG) conditions in randomly assigned order. Protocols were separated by a minimum of 3 days. Subjects exercised for 90 minutes (three, 30-minute segments) on a treadmill while wearing wilderness firefighter TPC and helmet in a heated room. Venous blood was drawn before and after exercise to measure hemoglobin (Hgb), hematocrit (Hct), serum osmolarity (OSM), and serum creatine phosphokinase (CPK). Vital signs and perceptual measures of exertion and thermal comfort were recorded during the protocol. Data were analyzed by the paired t-test. There were no differences in the change in heart rate (84 ± 27 vs. 85 ± 14 b·min-1, p = 0.9), core temperature rise (1.8 ± 0.6 vs. 1.9 ± 0.5° C, p = 0.39), or body mass lost (-1.72 ± 0.78 vs. -1.77 ± 0.58 kg, p = 0.7) between the conditions. There were no differences in the change in Hgb (0.49 ± 0.66 vs. 0.33 ± 1.11 g·dl-1, p = 0.7), Hct (1.22 ± 1.92 vs. 1.11 ± 3.62%, p = 0.9), OSM (1.67 ± 6.34 vs. 6.22 ± 11.39 mOsm·kg-1, p = 0.3), or CPK (22.2 ± 30.2 vs. 29.8 ± 19.4 IU·L-1, p = 0.5). Total distance walked (3.9 ± 0.5 vs. 4.0 ± 0.5 miles, p = 0.2), exercise interval (88.6 ± 3.5 vs. 88.4 ± 3.6 minutes, p = 0.8), and perceptual measures were similar between conditions. Compression garments worn beneath TPC did not acutely alter the physiologic response to exertion in TPC. With greater use in the general public related to endurance activities, the data neither encourage nor discourage CG use during uncompensable heat stress.

Influenza vaccine effectiveness among outpatients in the US Influenza Vaccine Effectiveness Network by study site 2011-2016.

BACKGROUND: Influenza vaccination is recommended for all US residents aged ≥6 months. Vaccine effectiveness (VE) varies by age, circulating influenza strains, and the presence of high-risk medical conditions. We examined site-specific VE in the US Influenza VE Network, which evaluates annual influenza VE at ambulatory clinics in geographically diverse sites. METHODS: Analyses were conducted on 27 180 outpatients ≥6 months old presenting with an acute respiratory infection (ARI) with cough of ≤7-day duration during the 2011-2016 influenza seasons. A test-negative design was used with vaccination status defined as receipt of ≥1 dose of any influenza vaccine according to medical records, registries, and/or self-report. Influenza infection was determined by reverse-transcription polymerase chain reaction. VE estimates were calculated using odds ratios from multivariable logistic regression models adjusted for age, sex, race/ethnicity, time from illness onset to enrollment, high-risk conditions, calendar time, and vaccination status-site interaction. RESULTS: For all sites combined, VE was statistically significant every season against all influenza and against the predominant circulating strains (VE = 19%-50%) Few differences among four sites in the US Flu VE Network were evident in five seasons. However, in 2015-16, overall VE in one site was 24% (95% CI = -4%-44%), while VE in two other sites was significantly higher (61%, 95% CI = 49%-71%; P = .002, and 53%, 95% CI = 33,67; P = .034). CONCLUSION: With few exceptions, site-specific VE estimates aligned with each other and overall VE estimates. Observed VE may reflect inherent differences in community characteristics of the sites and highlights the importance of diverse settings for studying influenza vaccine effectiveness.

Delirium and Dementia.

Approximately 35% to 37% of older emergency department (ED) patients will have delirium or dementia, which can negatively affect safe and appropriate clinical care. This article describes the epidemiology of delirium and dementia in the ED and how it affects clinical care and patient outcomes. Screening for delirium and dementia in the context of the busy ED environment, as well as their diagnostic evaluation and management, is discussed.

Scene Safety and Force Protection in the Era of Ultra-Potent Opioids.

Ultra-potent opioids (fentanyl, carfentanil) are now widely available and fueling an epidemic of overdose. First responders are increasingly exposed to these potent narcotics necessitating guidance for scene safety and force protection from medical directors. Reports in lay media have sensationalized accounts of exposure and harm that may lead providers to fear providing care to patients suspected of opioid overdose. The likelihood of prehospital providers suffering ill effects from opioid exposure during routine emergency medical services (EMS) operations is extremely low. We propose recommendation to assist medical directors in providing guidance and education to their providers minimizing the risk of provider exposure while allowing the delivery of prompt and appropriate care to patients with suspected overdose.

Delayed Detection of Spontaneous Bilateral Tubal Ectopic Pregnancies After Methotrexate Treatment.

BACKGROUND: Bilateral tubal ectopic pregnancies are a rare subset of ectopic pregnancy that can pose a diagnostic dilemma for clinicians. There is no distinct clinical presentation for bilateral tubal ectopic pregnancies, although they are typically associated with assistive reproductive techniques. In addition, there is no single diagnostic feature to help clinicians delineate bilateral tubal ectopic pregnancies from other types of ectopic pregnancy prior to passing the discriminatory zone (such as heterotopic pregnancy or twin ectopic [two gestational sacs in one tube]). Diagnosis is typically made via direct visualization intraoperatively and therefore treatment is usually surgical. CASE REPORT: We present a case of spontaneous bilateral tubal ectopic pregnancies diagnosed 7 days apart via transvaginal ultrasound. The patient presented to the emergency department with pelvic pain on the contralateral side of her previously diagnosed ectopic pregnancy and vaginal spotting. Bilateral adnexal masses were visualized on ultrasound and her serum beta-human chorionic gonadotropin level had a 5.9% decline from day 4 to day 7 after methotrexate administration 7 days prior; gynecology was consulted. The patient was successfully treated with an additional dose of intramuscular methotrexate without any complications. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The implications of this case suggest that diagnosis of bilateral tubal ectopic pregnancies requires clinicians to have a high level of suspicion in any pregnant female with a suspected or known ectopic pregnancy who presents with pelvic pain regardless of prior diagnosis or treatment.

Cardiorespiratory Fitness Is Associated with Gait Changes among Firefighters after a Live Burn Training Evolution.

BACKGROUND: Recommendations have been proposed for minimum aerobic fitness among firefighters but it is unclear if those criteria relate to performance on the fireground. Less fit individuals fatigue more quickly than fit individuals when working at comparable intensity and may have gait changes, increasing risk of falls. We evaluated the effect of fatigue during a live burn evolution on gait parameters and functional balance comparing them to aerobic fitness levels. METHODS: A total of 24 firefighters had gait and balance tested before and after a live burn evolution. Data were stratified by aerobic fitness of greater/less than 14 metabolic equivalents (METs). RESULTS: Analysis of gait cycles measurements before and after the live burn evolution revealed that single leg stance, cycle, and swing time decreased (p < 0.05) but there were no differences in the other measures. There were no differences in time to complete the functional balance test, or errors committed before or after a live burn evolution. When firefighters were sorted by fitness level of 14 METs, there were no differences for errors or time before or after the live burn evolution. Balance data were analyzed using a linear regression. Individuals with lower fitness levels required more time to complete the test. CONCLUSION: A 14-MET criterion failed to distinguish gait or balance characteristics in this group. However, less fit firefighters did require more time to complete the balance test (p = 0.003). Aerobic fitness alone does not predict gait changes among firefighters following a live burn evolution but does appear to influence functional balance.

Pilot Study Examining the Effects of Atropine on Performance during Uncompensable Heat Stress.

UNLABELLED: In many operational scenarios, hypohydration can be corrected with oral rehydration following the work interval. Although rare, there are potential situations that require extended intervals of uncompensable heat stress exposure while working in personal protective equipment (PPE). Under these conditions, retention of body water may be valuable to preserve work capacity and reduce cardiovascular strain. We conducted a pilot study comparing intramuscular atropine sulfate versus saline placebo to establish the safety profile of the protocol and to provide pilot data for future investigations. Five, healthy, heat-acclimated subjects completed this crossover design laboratory study. Each subject performed up to one hour of exertion in a hot environment while wearing a chemical resistant coverall. Atropine sulfate (0.02 mg/kg) or an equivalent volume of sterile saline was administered by intramuscular injection. Core temperature, heart rate, perceptual measures, and changes in body mass were measured. All five subjects completed the acclimation period and both protocols. No adverse events occurred, and no pharmacologically induced delirium was identified. Change in body mass was less following exercise influenced by atropine sulfate (p = 0.002). Exertion time tended to be longer in the atropine sulfate arm (p = 0.08). Other measures appeared similar between groups. Intramuscular atropine sulfate reduced sweating and tended to increase the work interval under uncompensable heat stress when compared to saline placebo. Heart rate and temperature changes during exertion were similar in both conditions suggesting that the influence of an anticholinergic agent on thermoregulation may be minimal during uncompensable heat stress. KEY WORDS: thermoregulation; cholinolytic; anticholinergic; reaction time.

A Mobile Alert System for Preparing the Delivery of Radiation Mitigators.

BACKGROUND/AIM: A mobile system allowing hospital medical personnel to prepare for the administration of radiation mitigators prior to receiving casualties is desirable. MATERIALS AND METHODS: We evaluated a portable spectroscopic personal radiation detector for use as an ambulance-based unit for early detection and identification of gamma radiation. We tested the sensitivity, time-to-identification, and radionuclide identification accuracy rates, change in detector response to vehicle operation, interference from cardiac equipment, and internal versus external radiation source location. RESULTS: We detected radiation sources in each of 119 trials using a humanoid phantom in a moving ambulance with a primary radionuclide identification accuracy of 96%. Typical identification time was around two minutes (149±95 s). CONCLUSION: Our observations suggest this mobile system is a potential pre-hospital arrival tool allowing for rapid preparation of radiation mitigators.

Exertional heat illness: emerging concepts and advances in prehospital care.

Exertional heat illness is a classification of disease with clinical presentations that are not always diagnosed easily. Exertional heat stroke is a significant cause of death in competitive sports, and the increasing popularity of marathons races and ultra-endurance competitions will make treating many heat illnesses more common for Emergency Medical Services (EMS) providers. Although evidence is available primarily from case series and healthy volunteer studies, the consensus for treating exertional heat illness, coupled with altered mental status, is whole body rapid cooling. Cold or ice water immersion remains the most effective treatment to achieve this goal. External thermometry is unreliable in the context of heat stress and direct internal temperature measurement by rectal or esophageal probes must be used when diagnosing heat illness and during cooling. With rapid recognition and implementation of effective cooling, most patients suffering from exertional heat stroke will recover quickly and can be discharged home with instructions to rest and to avoid heat stress and exercise for a minimum of 48 hours; although, further research pertaining to return to activity is warranted.

The effects of ice slurry ingestion before exertion in Wildland firefighting gear.

PURPOSE: To investigate the effect of ice slurry ingestion precooling on body core temperature (Tc) during exertion in wildland firefighting garments in uncompensable heat stress. METHODS: On two separate trials, 10 males ingested 7.5 g·kg(-1) of either an ice slurry (0.1°C) or control beverage (20°C) during seated rest for 30 minutes prior to simulating the U.S. Forest Service Pack Test on a treadmill in wildland firefighting garments in a hot environment (38.8 ± 1.2°C, 17.5 ± 1.4% relative humidity). Deep gastric temperature, mean skin temperature (Tsk), and heart rate (HR) were recorded. Ratings of perceived exertion, thermal sensation, comfort, and sweating were assessed. RESULTS: Compared with ingestion of a temperate beverage, precooling with ice slurry before exertion in a hot environment reduced Tc during the first 30 minutes of the exercise bout. Exercise time and distance completed were not different between treatments. Skin temperature, heart rate, and perceptual responses rose in both conditions during exercise but did not differ by condition. CONCLUSION: Pretreatment with ice slurry prior to exertion in wildland firefighting garments results in a modest reduction in Tc during the first 30 minutes of exercise when compared to pretreatment with control beverage but the ice slurry precooling advantage did not persist throughout the 45-minute exercise protocol.

A randomized controlled trial of aspirin and exertional heat stress activation of platelets in firefighters during exertion in thermal protective clothing.

PURPOSE: Platelet aggregation is enhanced in firefighters following short bouts of work in thermal protective clothing (TPC). We sought to determine if aspirin therapy before and/or following exertion in TPC prevents platelet activation. METHODS: In a double-blind, placebo-controlled study, 102 firefighters were randomized to receive daily therapy (81 mg aspirin or placebo) for 14 days before and a single dose (325 mg aspirin or placebo) following exercise in TPC resulting in four potential assignments: aspirin before and after exercise (AA), placebo before and after exercise (PP), aspirin before and placebo after exercise (AP), and placebo before and aspirin after exercise (PA). Platelet closure time (PCT) was measured with a platelet function analyzer before the 2-week treatment, after the 2 week treatment period, immediately after exercise, and 30, 60, and 90 minutes later. RESULTS: Baseline PCT did not differ between groups. PCT changed over time in all four groups (p < 0.001) rising to a median of >300 seconds [IQR 99, 300] in AA and >300 [92, 300] in AP prior to exercise. Following exercise, median PCT decreased to in all groups. Median PCT returned to >300 seconds 30 minutes later in AA and AP and rose to 300 seconds in PA 60 minutes after exercise. CONCLUSIONS: Daily aspirin therapy blunts platelet activation during exertional heat stress and single-dose aspirin therapy following exertional heat stress reduces platelet activation within 60 minutes.

Validation of the OMNI Scale of Thermal Sensations.

Concurrent and construct validation of the OMNI Scale of Thermal Sensations was examined in a sample of 16 adult men and 5 adult women. Concurrent validity was established by regressing OMNI ratings of thermal sensation against core and skin temperatures obtained during treadmill walking while wearing firefighter thermal-protective clothing in temperatures between 33 and 35 degrees C. Construct validity was established by regressing the OMNI scale against a construct-specific visual analogue scale. OMNI scale responses accounted for statistically significant variance in both skin temperature and core temperature (48% and 51%, respectively) and visual analogue scale responses (84%). Concurrent and construct validity were established for the OMNI Scale of Thermal Sensations in healthy adults performing treadmill walking while wearing fire fighter thermal protective clothing.

Interceptor and Phantom Trials of EDNS at UPMC.

University of Pittsburgh Medical Center (UPMC) installed an Emergency Department Notification System (EDNS) in one of its hospitals. The system, manufactured by Thermo Fisher Scientific (Thermo Fisher Scientific, Inc., 81 Wyman Street, Waltham, MA 02454), consists of four NaI(Tl) scintillation detectors, a 2.5 L PVT gamma counter, a 512 channels multi-channel analyzer, a system controller, and a database-monitoring server. We evaluated a portable Interceptor Interceptor™ hand-held detector (Thermo Fisher Scientific, Inc., 81 Wyman Street, Waltham, MA 02454) as part of the system for potential ambulancebased early detection and warning unit. We present the minimum detectable activity, distance, and isotope identification success rates along with the change in detector response to various radioisotope sources placed in a Rando® humanoid phantom. (The Phantom Laboratory. P.O. Box 511, Salem, NY 12865-0511 USA). The present paper reports these results.

The effect of prolonged light intensity exercise in the heat on executive function.

OBJECTIVE: When people are involved in outdoor activities, it is important to be able to assess a situation and make rational decisions. The goal of this study is to determine the effects of 90 minutes of light-intensity exercise in a hot environment on executive functioning capabilities of healthy individuals. METHODS: In this prospective laboratory study, 40 healthy male and female subjects 18 to 45 years of age performed treadmill exercise while wearing athletic clothing and a backpack in either a hot or temperate environment. Vital signs, core and skin temperature, and perceptual measures (thermal sensation, sweating, comfort, and perceived exertion) were measured before, during, and after the treadmill test. Cognitive function was measured before and after the treadmill test using the Wisconsin Card Sorting Test (WCST) and a Psychomotor Vigilance Test (PVT). RESULTS: Subjects in the hot condition reached a similar core temp of 38.2° ± 0.5°C vs 37.7° ± 0.3°C (P = .325) in the temperate group but had a higher heart rate (P < .001) and skin temperature (P < .001). Hot and normal temperature groups did not differ in their PVT performance. There were more correct responses (P < .001), fewer errors (P < .001), and more conceptual responses (P = .001) on the WCST after exertion in both the hot room and normal temperature room conditions. Perseverations and perseverative errors (P = .002) decreased in both groups after exertion. CONCLUSIONS: Conditions of mild heat stress coupled with modest rehydration and short hiking treks do not appear to negatively affect executive function or vigilance.