Development of Field Tests for Cardiovascular Fitness Assessment in Wheelchair.

It is essential to consider both physique and physical fitness factors to minimize the risk of injuries and optimize athletic performance among elite athletes. Athletes with disabilities face limitations in fitness assessments compared to their healthy counterparts. The aim of this study was to revalidate established cardiovascular fitness assessment methods and develop field tests for wheelchair athletes. As representatives registered at the Korea Paralympic Committee's Athletes Training Center in Icheon, athletes with physical disabilities participating in para ice hockey (n = 14), who were capable of wheelchair control, were volunteered. Prior to cardiovascular fitness assessments using an ergometer and a shuttle run, demographic characteristics were surveyed, and physical measurements and muscle strength (grip strength) were recorded. All the participants performed one ergometer test based on cardiovascular fitness criteria, and for shuttle run validation, two trials were conducted using existing audio cues (National Physical Fitness 100, 20 m shuttle run). For the development of the shuttle run, considering wheelchair turning, signal-to-sound intervals were increased by 1 s and 1.5 s, respectively, in two trials. An analysis of the correlation with the maximal oxygen consumption (VO2max) in comparison to the reference criterion, an ergometer, demonstrated high correlations in the first trial (r = 0.738) and the second trial (r = 0.780). Similarly, significant correlations were observed with the maximum heart rate (HRmax) in the first trial (r = 0.689) and the second trial (r = 0.896). Thus, the 15 m shuttle run is validated as a field test for assessing cardiovascular fitness in athletes with disabilities. Correlation analysis with maximal oxygen uptake (VO2max) compared to the reference criterion, an ergometer, revealed a correlation of 0.815 with a 1 s interval audio cue and 0.355 with a 1.5 s interval audio cue. A high correlation was observed with the 1 s interval audio cue. Regarding the maximum heart rate (HRmax), the correlations were 0.665 with a 1 s interval audio cue. Once again, a high correlation was noted with the 1 s interval audio cue. The field test selected for measuring cardiovascular fitness in wheelchair athletes involved performing a 15 m shuttle run while in the wheelchair. The test utilized an audio cue with a 1 s increased interval between the signal sounds.

Determination of moderate walking intensity using step rate and VO2 reserve in healthy men.

OBJECTIVE: This study investigated step rates (SR) during overground walking to estimate the relative aerobic capacity that corresponds to a moderate intensity. METHODS: The present study utilized a repeated measure, within-subjects design incorporating a counterbalanced order. A total of twenty-three healthy men walked on a 119-meter oval track with artificial turf at self-selected pace (FP), 100, 120, and 140 steps/min for 6 min each while oxygen uptake (VO2), speed (in km/h), distance (in m), and steps (in steps/min) were measured. RESULTS: During FP, participants walked an average cadence of 117 ± 9.3 steps/minclose to 120 steps/min, which corresponds to 4.7 metabolic equivalents (METs). The estimated VO2 reserve was 30.5% of VO2 reserve at the FP and was close to the 120 steps/min of 33.3%. At the 100 and 140 steps/min, the VO2 reserve were 24.1% and 45.2%, respectively. The regression analysis revealed that an SR of 88.2 elicited 3METs and 17.1% of VO2reserve. Additionally, an SR of 129 elicited 5.9METs and 40% of VO2 reserve. CONCLUSIONS: This study demonstrated that a moderate walking intensity for young, healthy men corresponded to 128.9 steps per minute. A range of 120 ~ 140 steps/min for walking could be recommended as a general guideline for moderate-intensity exercise. However, concerning providing public guidelines, caution should be taken regarding determining the moderate walking intensity due to the individual's fitness level.

Comparison of finger flexion strength and muscular recovery of male lead sport climbers across climbing classes.

BACKGROUND/OBJECTIVE: The purpose of this study was to compare finger flexor strength (FS), finger flexor muscle recovery (FR), and forearm circumference (FC) across three different climbing classes in male lead sport climbers. METHODS: A total of 37 male lead sport climbers were classified into low (LC), intermediate (IC), and advanced classes (AC) categories according to the International Rock Climbing Research Association (IRCRA) Scale. All participants measured FS three times for both open grip (OG) and crimp grip (CG). Following FS measurement, the FR was observed immediately after the all-out training. The FC was measured twice using an inelastic tape. RESULTS: The FS differed significantly across climbing classes for both grip styles and hands, regardless of dominant hand, with the higher classes showing greater FS (all, p ≤ 0.001). FR was significantly higher in AC compared to IC and LC at 5 min (all, p ≤ 0.001), 10 min (all, p ≤ 0.005) and 15 min (all, p ≤ 0.005). The FC showed significant differences with climbing classes for both forearms. CONCLUSION: Climbing classes are associated with differences in FS, with higher class corresponding to greater FS. Similarly, climbing classes are linked to FR and FC, with higher classes being associated with faster recovery and larger FC.

Comparison of Korean School Students' Safety Accident Rates before and after COVID-19.

The COVID-19 pandemic has significantly affected various aspects of education, including the occurrence of injuries among Korean students. This study aims to analyze and compare injury rates in elementary, middle, and high schools before and after the pandemic and identify the associated factors. A non-experimental quantitative dataset compiled from the Korea School Safety Association's annual reports (2018-2022) was utilized. The data included information on school safety accidents among Korean children and adolescents during the COVID-19 pandemic. The dataset was analyzed based on factors such as time, location, type of accident, and injured body part. The findings revealed a decline in accidents during the early phase of the pandemic, followed by an increase after schools reopened. There were notable variations in the accidents in specific locations, types, and body parts affected during the pandemic, compared with the pre-pandemic period. This study highlights the importance of continuous monitoring, implementation of safety measures, and prioritization of physical activity programs and safety education to ensure a safe learning environment. Further research is recommended to track and address evolving school accidents in response to the pandemic and its aftermath.

Added Inspiratory Resistance Does Not Impair Cognitive Function and Mood State.

This study evaluated cognitive function and mood state with inspiratory resistance before and after maximal exercise in hypoxia. Nine healthy men (age = 25 ± 2 years) performed the Automated Neuropsychological Assessment Metrics-4th Edition (ANAM4) of the Stroop color-word test (SCWT) and total mood disturbance (TMD) before and after an incremental cycling exercise until volitional fatigue with four different inspiratory resistances (0, 1.5, 4.5, 7.5 cm H2O·L-1·s-1). There was no significant difference in the interference score of SCWT and TMD at normobaric, hypoxic conditions at four different inspiratory resistances. However, the interference score of SCWT was improved following maximal cycling exercise, whereas TMD was not improved. Inspiratory resistance did not have a deleterious effect on cognitive function and mood state in normobaric hypoxia after maximal cycling exercise. However, following maximal cycling exercise, cognitive function was improved.

Wellness Perception of South Korean Elementary School Students during the COVID-19 Endemic.

This study aimed to analyze health management awareness among South Korean elementary school students in COVID-19 endemic areas. METHODS: Using convenience sampling, 675 South Korean elementary school students (age 11-12 years old) were selected as participants in July 2023. Data for the study were collected via online and offline surveys between July and August 2023. The collected data were subjected to frequency, reliability, and multicollinearity analyses, independent sample t-tests, and importance-performance analysis (IPA). RESULTS: The findings indicated the following: (1) There was no significant difference in health management performance between male and female children. (2) Children who had not experienced COVID-19 infection, had a higher level of "hygiene management" performance. (3) Among children who did not wear masks during physical activity, "mental health management" and "physical activity management" performance were higher, while "hygiene management" performance was lower. (4) The IPA matrix analysis revealed that, compared to the COVID-19 pandemic period, "physical activity management", "dietary habit management", and "sleep management" still required improvement, while "hygiene management" and "disease management" appeared to have decreased due to the relaxation of epidemic control efforts. CONCLUSION: As per the study's findings, schools, local communities, and families should make efforts to develop and implement preventive and individualized health management programs that consider the individual characteristics of their children.

An Analysis of Health Perceptions and Performance in Elementary Students in Korea during the ongoing COVID-19 Pandemic.

During the coronavirus disease 2019 (COVID-19) pandemic, social distancing guidelines changed lifestyles, including increased sedentary time, physical inactivity, and disrupted sleep patterns among children. The purpose of the present study is to analyze the health awareness (mental health, disease, physical activity, sleep, eating habit, and hygiene health management) of elementary school students during the COVID-19 pandemic, and use the importance-performance analysis (IPA) technique to identify gender differences in health perceptions. We collected data on 1006 students, which was analyzed using frequency analysis, reliability testing, independent sample t-tests, and importance-performance analysis (IPA). A median importance value of 0.163 and a median performance value of 4.048 were selected as cross points to distribute the IPA matrix into four quadrants. The highest performance was given for wearing a mask and sanitary practice; the IPA matrix indicated that the sense of belonging, happiness, trust, and movement activity were located in quadrant I. Children's regular physical activity and level of physical activity were low, especially that of girls. Children's sleep management was poor. Their physical activity and sleep-related factors must be improved under the facilitation of the national government, public education institutions, and families.

Differential Cutaneous Thermal Sensitivity in Humans: Method of Limit vs. Method of Sensation Magnitude.

INTRODUCTION: The method of limits (MLI) and method of level (MLE) are commonly employed for the quantitative assessment of cutaneous thermal sensitivity. Thermal sensation and thermal comfort are closely related and thermal sensations evoked from the peripheral thermoreceptors play an important role in thermoregulatory response to maintain normal body temperature. The purpose of this study was to compare the regional distribution of cutaneous warm and cold sensitivity between MLI and the method of sensation magnitude (MSM). METHOD: Twenty healthy men completed MLI and MSM to compare the regional distribution of cutaneous warm and cold sensitivity in the thermal neutral condition. The subjects rested on a bed in a supine position for 20 min. Next, the cutaneous thermal sensitivity of ten body sites was assessed by the means of MLI and MSM for both warmth and cold stimuli. RESULTS: The absolute mean heat flux in MLI and thermal sensation magnitude in MSM showed significantly greater sensitivity to cold than to warm stimulation (p < 0.01), together with a similar pattern of regional differences across ten body sites. Both sensory modalities indicated acceptable reliability (SRD%: 6.29-8.66) and excellent reproducibility (ICC: 0.826-0.906; p < 0.01). However, the Z-sore distribution in MSM was much narrower than in MLI, which may limit the test sensitivity for the detection of sensory disorders and/or comparison between individuals. CONCLUSION: The present results showed that both MLI and MSM are effective means for evaluating regional cutaneous thermal sensitivity to innocuous warm and cold stimulations to a strong degree of reliability and reproducibility.

The Associations between Physical Fitness, Complex vs Simple Movement, and Academic Achievement in a Cohort of Fourth Graders.

This study analyzed the correlation between elementary school students' body composition, physical activity, physical fitness, movement ability, and academic achievement. Movements ranged from simple actions to complex movements requiring executive functioning. In total, 110 fourth graders (60 boys, 50 girls) participated in this experiment. Body composition (BMI, % of body fat), physical activity (pedometer), physical fitness (muscular strength, endurance, power, flexibility, and VO2max), and complex movement abilities (Illinois Agility test, soda pop hand test, and soda pop foot test) were measured. Regression modeling of body composition and fitness/activity variables was able to account for 30.5% of the variation of total academic scores in females, but only 4.3% in males. No individual tests were reliably correlated with multiple academic outcomes in males. However, hand and foot soda pop times, as well as Illinois Agility scores, were repeatedly correlated with academic outcomes in females, each correlating with 4 of the 6 academic scores. Body composition and physical activity level did not correlate with academic achievement, and simple physical fitness showed a low correlation with academic achievement in both boys and girls. On the other hand, complex, cognitively demanding movements such as the Illinois Agility, soda pop hand, and soda pop foot tests had consistent correlations with academic achievement in girls, but not in boys.

Occupational physical activity and cardiovascular disease in the United States.

BACKGROUND: Emerging evidence, predominately from European and Asian countries, describes opposing effects of occupational physical activity (OPA) and leisure-time physical activity (LTPA) on cardiovascular health. This analysis examined cardiovascular disease (CVD) prevalence associated with OPA and LTPA. METHODS: This cross-sectional analysis of 2015 National Health Interview Survey data (n=16 974) employed logistic regression to estimate odds (OR) of self-reported CVD (coronary heart disease, heart attack, stroke or angina) with self-reported total occupational activity (TOA), occupational exertion (OE), occupational standing and walking (OSW) and LTPA. OPA was measured using two questions: 'How often does your job involve…' (1) 'repeated lifting, pushing, pulling or bending?' (OE) and (2) 'standing or walking around?' (OSW) with responses on a 5-item Likert scale (0=never, 4=always). TOA was categorised similarly after summing OE and OSW scores. LTPA was defined as 0, 1-149 or ≥150 min/week of moderate-to-vigorous activity. All models adjusted for common socioeconomic variables and additional analyses were stratified by sex, smoking status and LTPA. RESULTS: Odds for CVD were higher when 'always' performing TOA (OR 1.99 95% CI 1.12 to 3.53), OE (OR 2.15, 95% CI 1.45 to 3.19) or OSW (OR 1.84, 95% CI 1.07 to 3.17) compared with 'never'. When restricting to never-smokers, odds for CVD were higher when 'always' performing TOA (OR 3.00, 95% CI 1.38 to 6.51) and OE (OR 3.00, 95% CI 1.80 to 5.02) versus 'never'. CONCLUSION: Associations of high OPA with CVD were equally apparent across sexes, stronger in lower LTPA levels and stronger in never-smokers. While uncontrolled confounding is still possible, even after extensive adjustment, the seemingly paradoxical adverse associations with OPA and CVD should be investigated further.

Psychophysiological Responses in Emergency Medical Technician Students during Simulated Work Activities in a Hot Environment.

This study compared physiological responses and cognitive performance during simulated work activities in heat to a thermoneutral condition. First responders perform physically demanding activities in a hot environment which may impose additional burdens on tactical personnel during daily tasks. Ten healthy (8 men and 2 women) participants performed two consecutive simulated work activities with two repetitions of each activity (10 min walking on treadmill and 15 sandbag lifts) under heat and thermoneutral conditions. A Stroop color word test (SCWT) and total mood disturbance (TMD) were obtained at first and second baseline (B1, B2), after a 30-min resting period (B3), and recovery (R1). At the end of the trial, core temperature (Tc), skin temperature (tsk), and mean body temperature (Tb) were higher in the heat condition compared to neutral condition (all p ≤ 0.05), whereas oxygen uptake, heart rate, and mean arterial pressure were not significantly different between conditions. There were no differences in scores of SCWT and TMD between conditions. However, TMD was significantly improved after two successive bouts of exercise compared to B3 (all p ≤ 0.05). This investigation shows that two successive simulated work activities did not induce the detrimental influence on thermoregulatory and cognitive responses. Extended work activities in a hot and humid environment may impose a psychophysiological burden and need to be investigated.

The effects of a loaded rucksack and weighted vest on metabolic cost and stride frequency in female adults.

This study evaluated the metabolic cost and stride frequency during exercise while wearing an evenly distributed weight vest in recreationally fit women. Nine healthy women performed a modified Balke treadmill test until volitional fatigue in one of three conditions; (1) unloaded (2) rucksack and (3) weighted vest. Wearing a weighted vest did not show improvement of V̇O2peak, HRpeak, peak stride frequency or average stride frequency (all p ≥ 0.05). However, total time of exercise was significantly longer in the evenly distributed weight vest condition compared to the rucksack condition (p = 0.024) despite similar V̇O2peak and HRpeak. These results may provide practical information when females in tactical populations are preparing for missions in which heavy loads must be carried. Practitioner summary: This study compared the effects of load carriage mode on metabolic cost and stride frequency during graded exercise in females. The weighted vest showed significantly longer exercise time despite similar V̇O2peak and HRpeak. Development of standardised weight distribution mode may serve as an advantageous strategy for females in tactical settings. Abbreviations: HR: heart rate; V̇O2: oxygen uptake; RPE: rating of perceived exertion; V̇O2peak: peak oxygen uptake; HRpeak: peak heart rate.

Investigating Effects of Cold Water Hand Immersion on Selective Attention in Normobaric Hypoxia.

This study investigated the effect of cold-water hand immersion on selective attention as measured by the Stroop Color Word Test in nomorbaric normoxia and hypoxia. Ten healthy men rested for 60 min, after which they immersed their non-dominant hand into 5 °C water for 15 min. The interference score of the Stroop Color Word Test and thermal sensation were measured at baseline in the final 5 min of resting and in the final 5 min of cold water hand immersion. The interference score was not influenced by hypoxia but was found to be significantly improved compared to resting in both conditions during cold water hand immersion. Selective attention improved during 15 min of cold-water hand immersion, with increased thermal sensations rated as "very cool" of the immersed arm. Cold-water hand immersion may be helpful in improving cognitive function in normoxia and normobaric hypoxia.

Intersegmental differences in facial warmth sensitivity during rest, passive heat and exercise.

Background: Increased facial warmth sensations could lead to thermal discomfort, and different facial regions may demonstrate concurrent temperature differences. The study aim was examining facial warmth sensitivity differences by facial region under differing environmental conditions. Methods: Twelve men had heat flux measurements of six facial regions during 30 min each of rest in thermoneutral conditions (25 °C, 30% relative humidity (RH)), rest in warm conditions (40 °C, 30% RH), and cycling at 400 W of metabolic heat production (40 °C, 30% RH). Results: The forehead demonstrated highest temperatures at termination of all study conditions; lowest temperatures were noted for the nose under thermoneutral conditions and chin during warmth and exercise conditions. Five of six facial regions demonstrated significant differences in warmth sensitivity, decreasing to two of six regions during warm conditions and one of six regions during exercise, with the upper lip most sensitive in all conditions. Body thermal comfort (TC) perceptions, regressed individually on mean facial temperature (Tface) vs. core temperature (Tco), indicated that Tface was significantly more related than Tco to perceived TC (p = .001). Perceived TC, regressed individually on perceived overall body thermal sensation (TS) vs. facial TS, demonstrated that Tface was significantly more related to perceived TC (p = .004). Conclusion: There were regional differences in facial warmth sensitivity together with different facial temperatures moving toward equilibration when the body is subjected to heat-producing activities. Perceptions of TC were more strongly related to Tface than to Tco or overall body TS.

Heat stress assessment during intermittent work under different environmental conditions and clothing combinations of effective wet bulb globe temperature (WBGT).

This study examined whether different combinations of ambient temperature and relative humidity for the effective wet bulb globe temperature, in conjunction with two different levels of clothing adjustment factors, elicit a similar level of heat strain consistent with the current threshold limit value guidelines. Twelve healthy, physically active men performed four 15-min sessions of cycling at a fixed rate of metabolic heat production of 350 watts. Each trial was separated by a 15-min recovery period under four conditions: (1) Cotton coveralls + dry condition (WD: 45.5 °C dry-bulb, 15% relative humidity); (2) Cotton coveralls + humid condition (WH: 31 °C dry-bulb, 84% relative humidity); (3) Protective clothing + dry condition (PD: 30 °C dry-bulb, 15% relative humidity); and (4) Protective clothing + humid condition (PH: 20 °C dry-bulb, 80% relative humidity). Gloves (mining or chemical) and headgear (helmet or powered air-purifying respirator) were removed during recovery with hydration ad libitum. Rectal temperature (Tre), skin temperature (Tsk), physiological heat strain (PSI), perceptual heat strain (PeSI), and body heat content were calculated. At the end of the 2-hr trials, Tre remained below 38 °C and the magnitude of Tre elevation was not greater than 1 °C in all conditions (WD: 0.9, WH: 0.8, WH: 0.7, and PD: 0.6 °C). However, Tsk was significantly increased by approximately 2.1 ± 0.8 °C across all conditions (all p ≤ 0.001). The increase in Tsk was the highest in WD followed by PD, WH, and PH conditions (all p ≤ 0.001). Although PSI and PeSI did not indicate severe heat strain during the 2-hr intermittent work period, PSI and PeSI were significantly increased over time (p ≤ 0.001). This study showed that core temperature and heat strain indices (PSI and PeSI) increased similarly across the four conditions. However, given that core temperature increased continuously during the work session, it is likely that the American Conference of Governmental Industrial Hygienist's TLV® upper limit core temperature of 38.0 °C may be surpassed during extended work periods under all conditions.

Cold-induced vasodilation responses before and after exercise in normobaric normoxia and hypoxia.

PURPOSE: Cold-induced vasodilation (CIVD) is known to protect humans against local cold injuries and improve manual dexterity. The current study examined the effects of metabolic heat production on cold-induced vasodilation responses in normobaric hypoxia and normoxia. METHODS: Ten participants immersed their non-dominant hand into 5 °C water for 15 min. Minimum finger temperature (Tmin), maximum finger temperature (Tmax), onset time, amplitude, and peak time were measured before and after exercise under normoxia (21% O2) and two levels of normobaric hypoxia (17% O2 and 13% O2). RESULTS: Neither Tmin nor amplitude was affected by hypoxia. However, Tmax was significantly decreased by hypoxia while reduction in onset time and peak time trended towards significance. Tmin, Tmax, and amplitude were significantly higher during post-exercise CIVD than pre-exercise CIVD. CONCLUSION: The CIVD response may be negatively affected by the introduction of hypoxia whereas metabolic heat production via exercise may counteract adverse effects of hypoxia and improve CIVD responses.

Using trunk posture to monitor heat strain at work.

This study aimed to determine if trunk posture during walking is related to increases in rectal temperature (Tre). 24 males treadmill walked in one of four conditions (1): 30 min at 3.0 mph and 0% grade, 20 °C and 50% relative humidity (RH), wearing healthcare worker (HCW) PPE; (2): 30 min at 3.0 mph and 0% grade, 27.5 °C and 60% RH, HCW PPE; (3): 30 min at 3.0 mph and 0% grade, 32.5 °C and 70% RH, HCW PPE; and (4): 40 min at 40% VO2max, 30 °C and 70% RH, wearing firefighter PPE. Trunk posture (Zephyr BioHarness 3) and Tre were measured continuously. Tre was positively related to trunk posture, controlling for covariates (B = 3.49, p < .001). BMI and age moderated this relationship (Tre×age, B = 0.76, p < .001; Tre*BMI, B = -1.85, p < .001). Trunk posture measurement may be useful in monitoring fall potential and magnitude of heat stress of workers in hot environments. Practitioner Summary: Occupational hyperthermia increases worker risk for heat illness and injury but is difficult to monitor in the field. This investigation shows that trunk posture is independently and positively related to core temperature. Non-invasive measurement or visual inspection of trunk posture could provide novel insight on individual heat strain level.

Comparison of Thermal Manikin Modeling and Human Subjects' Response During Use of Cooling Devices Under Personal Protective Ensembles in the Heat.

IntroductionPersonal protective equipment (PPE) recommended for use in West Africa during the Ebola outbreak increased risk for heat illness, and countermeasures addressing this issue would be valuable.Hypothesis/ProblemThe purpose of this study was to examine the physiological impact and heat perception of four different personal cooling devices (PCDs) under impermeable PPE during low-intensity exercise in a hot and humid environment using thermal manikin modeling and human testing. METHODS: Six healthy male subjects walked on a treadmill in a hot/humid environment (32°C/92% relative humidity [RH]) at three metabolic equivalents (METs) for 60 minutes wearing PPE recommended for use in West Africa and one of four different personal cooling devices (PCDs; PCD1, PCD2, PCD3, and PCD4) or no PCD for control (CON). The same ensembles were tested with thermal manikin modeling software in the same conditions to compare the results. RESULTS: All PCDs seemed to reduce physiological heat stress characteristics when worn under PPE compared to CON. Both the manikin and human testing provided similar results in core temperature (Tc) and heat sensation (HS) in both magnitude and relationship. While the manikin and human data provided similar skin temperature (Tsk) characterization, Tsk estimation by the manikin seemed to be slightly over-estimated. Weight loss, as estimated by the manikin, was under-estimated compared to the human measurement. CONCLUSION: Personal cooling device use in conjunction with impermeable PPE may be advantageous in mitigating physiological and perceptual burdens of heat stress. Evaluation of PCDs worn under PPE can be done effectively via human or manikin testing; however, Tsk may be over-estimated and weight loss may be under-estimated. Thermal manikin testing of PCDs may provide fast and accurate information to persons recommending or using PCDs with PPE. QuinnT, KimJH, SeoY, CocaA. Comparison of thermal manikin modeling and human subjects' response during use of cooling devices under personal protective ensembles in the heat. Prehosp Disaster Med. 2018;33(3):279-287.

Effects of 5-Day Heat Acclimation on Workers Wearing Personal Protective Clothing.

Introduction: Elevated ambient temperature and personal protective clothing (PPC) induce physiological strain which may be counteracted by heat acclimation. The purpose of this study was to determine if 5-day heat acclimation training (HAT) improves thermal and perceptual responses while wearing chemical, biological, radiological, and nuclear (CBRN) PPC. Methods: Nine healthy men completed a heat stress test (walking for one hour with CBRN PPC) in 35°C and 50% relative humidity (RH) before and after 5-day HAT. The HAT consisted of five consecutive days of two 45-minute cycling sessions (50% VO2max) wearing athletic clothing separated by a 15 min rest in 45°C and 20% RH. Results of the pre- and post-HAT heat stress tests were compared. Results: Heat acclimation was seen through 5-day HAT; however, thermoregulatory responses did not improve while wearing CBRN PPC. Improvement (p<0.05, day 1 vs. day 5 HAT) in skin temperature (38.0±0.5°C vs. 37.6±0.5°C), body temperature (38.6±0.4°C vs. 38.3±0.4°C), sweat rate (2.26±0.3kg vs. 2.64±0.3kg), RPE (15.8±2.4 vs. 13.9±3.1), and heat perception (5.7±0.6 vs. 4.9±1.0) were noted. However, no physiological or perceptual improvements (p>0.05) were found in the post-HAT heat stress test. Conclusions: Heat acclimation adaptations may be blunted by CBRN PPC, thus requiring differing or extended HAT.

The Effect of Inspiratory Resistance on Exercise Performance and Perception in Moderate Normobaric Hypoxia.

Seo, Yongsuk, Jeremiah Vaughan, Tyler D. Quinn, Brittany Followay, Raymond Roberge, Ellen L. Glickman, and Jung-Hyun Kim. The effect of inspiratory resistance on exercise performance and perception in moderate normobaric hypoxia. High Alt Med Biol. 18:417-424, 2017. PURPOSE: Respirators are simple and efficient in protecting workers against toxic airborne substances; however, their use may limit the physical performance of workers. The purpose of this study was to determine the effect of inspiratory resistance on physical performance and breathing perception in normobaric hypoxia. METHOD: Nine healthy men wore a tight-fitting respiratory mask outfitted with one of four different inspiratory resistors (R) (0, 1.5, 4.5, 7.5 cm H2O/L/Sec) while exercising at normobaric hypoxia (17% O2) at submaximal exercise workloads of 50, 100, and 150 W on a cycle ergometer for 10 minutes each, followed by a maximal oxygen uptake (VO2max) test to exhaustion. RESULTS: Maximal power output at R7.5 was significantly lower than R0 (p = 0.016) and R1.5 (p = 0.035). Respiration rate was significantly reduced at R4.5 (p = 0.011) and R7.5 (p ≤ 0.001) compared with R0. Minute ventilation was significantly decreased in R7.5 compared with R0 (p = 0.003), R1.5 (p = 0.010), and R4.5 (p = 0.016), whereas VO2 was not significantly changed. Breathing comfort (BC) and breathing effort (BE) were significantly impaired in R7.5 (BC: p = 0.025, BE: p = 0.001) and R4.5 (BC: p = 0.007, BE: p = 0.001) compared with R0, but rating of perceived exertion (RPE) remained unchanged. CONCLUSIONS: Added inspiratory resistance limited maximal power output and increased perceptions of BC and BE in normobaric hypoxia. However, low-to-moderate inspiratory resistance did not have a deleterious effect on VO2 or RPE at submaximal or maximal exercise. Perceptual and physiological characteristics of respirators of varying inspiratory resistances should be considered by manufacturers and end users during design and respirator selection processes.