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1.
J Occup Environ Hyg ; 20(9): 414-425, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37267511

RESUMO

The impact of water consumption bolus volume and frequency on hydration biomarkers during work in the heat is unknown. In a randomized, crossover fashion, eight males consumed either 500 mL of water every 40 min or 237 mL of water every 20 min during 2 hr of continuous walking at 6.4 kph, 1.0% grade in a 34 °C/30% relative humidity environment, followed by 2 hr of rest. Hydration biomarkers and variables were assessed pre-work, post-work, and after the 2 hr recovery. There were no differences in body mass between trials at any time point (all p > 0.05). Percent change in plasma volume during work was not different when 237 mL of water was repeatedly consumed (-1.6 ± 8.2%) compared to 500 mL of water (-1.3 ± 3.0%, p = 0.92). Plasma osmolality was maintained over time (p = 0.55) with no difference between treatments (p = 0.21). When consuming 500 mL of water repeatedly, urine osmolality was lower at recovery (205 ± 108 mOsmo/L) compared to pre-work (589 ± 95 mOsmo/L, p < 0.01), different from repeatedly consuming 237 mL of water which maintained urine osmolality from pre-work (548 ± 144 mOsmo/L) through recovery (364 ± 261 mOsmo/L, p = 0.14). Free water clearance at recovery was greater with repeated consumption of 500 mL of water (1.2 ± 1.0 mL/min) compared to 237 mL of water (0.4 ± 0.8 mL/min, p = 0.02). Urine volume was not different between treatments post-work (p = 0.62), but greater after 2 hr of recovery when repeatedly consuming 500 mL of water compared to 237 mL (p = 0.01), leading to greater hydration efficiency upon recovery with repeated consumption of 237 mL of water (68 ± 12%) compared to 500 mL (63 ± 14%, p = 0.01). Thirst and total gastrointestinal symptom scores were not different between treatments at any time point (all p > 0.05). Body temperatures and heart rate were not different between treatments at any time point (all p > 0.05). Drinking larger, less frequent water boluses or drinking smaller, more frequent water boluses are both reasonable strategies to promote adequate hydration and limit changes in body mass in males completing heavy-intensity work in the heat.


Assuntos
Desidratação , Ingestão de Líquidos , Humanos , Masculino , Desidratação/prevenção & controle , Ingestão de Líquidos/fisiologia , Exercício Físico/fisiologia , National Institute for Occupational Safety and Health, U.S. , Concentração Osmolar , Estados Unidos , Água , Equilíbrio Hidroeletrolítico/fisiologia
2.
Medicina (Kaunas) ; 56(10)2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-33066469

RESUMO

Background and objectives: Exertional heat stroke (EHS) is a potentially lethal, hyperthermic condition that warrants immediate cooling to optimize the patient outcome. The study aimed to examine if a portable cooling vest meets the established cooling criteria (0.15 °C·min-1 or greater) for EHS treatment. It was hypothesized that a cooling vest will not meet the established cooling criteria for EHS treatment. Materials and Methods: Fourteen recreationally active participants (mean ± SD; male, n = 8; age, 25 ± 4 years; body mass, 86.7 ± 10.5 kg; body fat, 16.5 ± 5.2%; body surface area, 2.06 ± 0.15 m2. female, n = 6; 22 ± 2 years; 61.3 ± 6.7 kg; 22.8 ± 4.4%; 1.66 ± 0.11 m2) exercised on a motorized treadmill in a hot climatic chamber (ambient temperature 39.8 ± 1.9 °C, relative humidity 37.4 ± 6.9%) until they reached rectal temperature (TRE) >39 °C (mean TRE, 39.59 ± 0.38 °C). Following exercise, participants were cooled using either a cooling vest (VEST) or passive rest (PASS) in the climatic chamber until TRE reached 38.25 °C. Trials were assigned using randomized, counter-balanced crossover design. Results: There was a main effect of cooling modality type on cooling rates (F[1, 24] = 10.46, p < 0.01, η2p = 0.30), with a greater cooling rate observed in VEST (0.06 ± 0.02 °C·min-1) than PASS (0.04 ± 0.01 °C·min-1) (MD = 0.02, 95% CI = [0.01, 0.03]). There were also main effects of sex (F[1, 24] = 5.97, p = 0.02, η2p = 0.20) and cooling modality type (F[1, 24] = 4.38, p = 0.047, η2p = 0.15) on cooling duration, with a faster cooling time in female (26.9 min) than male participants (42.2 min) (MD = 15.3 min, 95% CI = [2.4, 28.2]) and faster cooling duration in VEST than PASS (MD = 13.1 min, 95% CI = [0.2, 26.0]). An increased body mass was associated with a decreased cooling rate in PASS (r = -0.580, p = 0.03); however, this association was not significant in vest (r = -0.252, p = 0.39). Conclusions: Although VEST exhibited a greater cooling capacity than PASS, VEST was far below an acceptable cooling rate for EHS treatment. VEST should not replace immediate whole-body cold-water immersion when EHS is suspected.


Assuntos
Golpe de Calor , Hipertermia , Adulto , Temperatura Corporal , Temperatura Baixa , Estudos Cross-Over , Feminino , Febre , Temperatura Alta , Humanos , Masculino , Adulto Jovem
4.
Ann Emerg Med ; 69(3): 347-352, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27865532

RESUMO

STUDY OBJECTIVE: We investigated the efficacy of tarp-assisted cooling as a body cooling modality. METHODS: Participants exercised on a motorized treadmill in hot conditions (ambient temperature 39.5°C [103.1°F], SD 3.1°C [5.58°F]; relative humidity 38.1% [SD 6.7%]) until they reached exercise-induced hyperthermia. After exercise, participants were cooled with either partial immersion using a tarp-assisted cooling method (water temperature 9.20°C [48.56°F], SD 2.81°C [5.06°F]) or passive cooling in a climatic chamber. RESULTS: There were no differences in exercise duration (mean difference=0.10 minutes; 95% CI -5.98 to 6.17 minutes or end exercise rectal temperature (mean difference=0.10°C [0.18°F]; 95% CI -0.05°C to 0.25°C [-0.09°F to 0.45°F] between tarp-assisted cooling (48.47 minutes [SD 8.27 minutes]; rectal temperature 39.73°C [103.51°F], SD 0.27°C [0.49°F]) and passive cooling (48.37 minutes [SD 7.10 minutes]; 39.63°C [103.33°F], SD 0.40°C [0.72°F]). Cooling time to rectal temperature 38.25°C (100.85°F) was significantly faster in tarp-assisted cooling (10.30 minutes [SD 1.33 minutes]) than passive cooling (42.78 [SD 5.87 minutes]). Cooling rates for tarp-assisted cooling and passive cooling were 0.17°C/min (0.31°F/min), SD 0.07°C/min (0.13°F/min) and 0.04°C/min (0.07°F/min), SD 0.01°C/min (0.02°F/min), respectively (mean difference=0.13°C [0.23°F]; 95% CI 0.09°C to 0.17°C [0.16°F to 0.31°F]. No sex differences were observed in tarp-assisted cooling rates (men 0.17°C/min [0.31°F/min], SD 0.07°C/min [0.13°F/min]; women 0.16°C/min [0.29°F/min], SD 0.07°C/min [0.13°F/min]; mean difference=0.02°C/min [0.04°F/min]; 95% CI -0.06°C/min to 0.10°C/min [-0.11°F/min to 0.18°F/min]). Women (0.04°C/min [0.07°F/min], SD 0.01°C/min [0.02°F/min]) had greater cooling rates than men (0.03°C/min [0.05°F/min], SD 0.01°C/min [0.02°F/min]) in passive cooling, with negligible clinical effect (mean difference=0.01°C/min [0.02°F/min]; 95% CI 0.001°C/min to 0.024°C/min [0.002°F/min to 0.04°F/min]). Body mass was moderately negatively correlated with the cooling rate in passive cooling (r=-0.580) but not in tarp-assisted cooling (r=-0.206). CONCLUSION: In the absence of a stationary cooling method such as cold-water immersion, tarp-assisted cooling can serve as an alternative, field-expedient method to provide on-site cooling with a satisfactory cooling rate.


Assuntos
Crioterapia/métodos , Febre/terapia , Adulto , Temperatura Corporal , Estudos Cross-Over , Crioterapia/instrumentação , Feminino , Humanos , Masculino , Adulto Jovem
5.
J Sports Sci ; 35(9): 828-834, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27268072

RESUMO

This study examined the separate and combined effects of heat acclimation and hand cooling on post-exercise cooling rates following bouts of exercise in the heat. Seventeen non-heat acclimated (NHA) males (mean ± SE; age, 23 ± 1 y; mass, 75.30 ± 2.27 kg; maximal oxygen consumption [VO2 max], 54.1 ± 1.3 ml·kg-1·min-1) completed 2 heat stress tests (HST) when NHA, then 10 days of heat acclimation, then 2 HST once heat acclimated (HA) in an environmental chamber (40°C; 40%RH). HSTs were 2 60-min bouts of treadmill exercise (45% VO2 max; 2% grade) each followed by 10 min of hand cooling (C) or no cooling (NC). Heat acclimation sessions were 90-240 min of treadmill or stationary bike exercise (60-80% VO2 max). Repeated measures ANOVA with Fishers LSD post hoc (α < 0.05) identified differences. When NHA, C (0.020 ± 0.003°C·min-1) had a greater cooling rate than NC (0.013 ± 0.003°C·min-1) (mean difference [95%CI]; 0.007°C [0.001,0.013], P = 0.035). Once HA, C (0.021 ± 0.002°C·min-1) was similar to NC (0.025 ± 0.002°C·min-1) (0.004°C [-0.003,0.011], P = 0.216). Hand cooling when HA (0.021 ± 0.002°C·min-1) was similar to when NHA (0.020 ± 0.003°C·min-1) (P = 0.77). In conclusion, when NHA, C provided greater cooling rates than NC. Once HA, C and NC provided similar cooling rates.


Assuntos
Aclimatação , Temperatura Baixa , Exercício Físico/fisiologia , Mãos/fisiologia , Temperatura Alta , Regulação da Temperatura Corporal , Mãos/anatomia & histologia , Força da Mão , Humanos , Masculino , Adulto Jovem
6.
Artigo em Inglês | MEDLINE | ID: mdl-38541370

RESUMO

This study compared physiological responses to two work/rest cycles of a 2:1 work-to-rest ratio in a hot environment. In a randomized crossover design, fourteen participants completed 120 min of walking and rest in the heat (36.3 ± 0.6 °C, 30.2 ± 4.0% relative humidity). Work/rest cycles were (1) 40 min work/20 min rest [40/20], or (2) 20 min work/10 min rest [20/10], both completing identical work. Core temperature (Tc), skin temperature (Tsk), heart rate (HR), nude body mass, and perception of work were collected. Comparisons were made between trials at equal durations of work using three-way mixed model ANOVA. Tc plateaued in [20/10] during the second hour of work (p = 0.93), while Tc increased in [40/20] (p < 0.01). There was no difference in maximum Tc ([40/20]: 38.08 ± 0.35 °C, [20/10]: 37.99 ± 0.27 °C, p = 0.22) or end-of-work Tsk ([40/20]: 36.1 ± 0.8 °C, [20/10]: 36.0 ± 0.7 °C, p = 0.45). End-of-work HR was greater in [40/20] (145 ± 25 b·min-1) compared to [20/10] (141 ± 27 b·min-1, p = 0.04). Shorter work/rest cycles caused a plateau in Tc while longer work/rest cycles resulted in a continued increase in Tc throughout the work, indicating that either work structure could be used during shorter work tasks, while work greater than 2 h in duration may benefit from shorter work/rest cycles to mitigate hyperthermia.


Assuntos
Temperatura Corporal , Temperatura Alta , Humanos , Temperatura Corporal/fisiologia , Regulação da Temperatura Corporal/fisiologia , Frequência Cardíaca/fisiologia , Temperatura Cutânea , Temperatura
7.
J Am Coll Health ; 70(5): 1451-1456, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-32813619

RESUMO

Purpose: The purpose of this study was to extend research on napping and sleep behaviors in collegiate athletes, and to compare nappers and non-nappers on sleep quality and duration. Methods: Current varsity, club, and intramural athletes between 18-29 years completed the Short Napping Behavior Scale, Pittsburgh Quality Sleep Index, Generalized Anxiety Disorder-7, and the Patient Health Questionnaire-9. Results: Approximately 72% (129/179) reported napping. There were no significant differences in outcomes between nap frequency groups on sleep quality (Χ2(3)=4.97, p=.17) or duration (Χ2(3)=1.20, p=.75). Moreover, there was no significant differences for nap length groups on sleep quality (Χ2(3)=7.03, p=.07) or duration (Χ2(3)=1.32, p=.72). Furthermore, there were no significant differences for nap timing groups on sleep quality (Χ2(3)=1.54, p=.67) or duration (Χ2(3)=2.43, p=.49). Conclusion: In a sample of collegiate athletes, nap frequency, length, and timing were not associated with worse sleep quality or duration.


Assuntos
Qualidade do Sono , Estudantes , Atletas , Humanos , Sono , Universidades
8.
J Sci Med Sport ; 24(8): 837-842, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34020884

RESUMO

OBJECTIVES: The purpose of this study was to determine thermoregulatory and cardiovascular effects of wearing men's lacrosse protective equipment during simulated lacrosse activities in the heat. DESIGN: We conducted a randomized, controlled, crossover study. METHODS: Thirteen healthy men (22 ±â€¯3 y, 76.2 ±â€¯8.9 kg, 181 ±â€¯6 cm, 16.06 ±â€¯6.16% body fat) completed two matched exercise trials in the heat (WBGT: 25.5 ±â€¯0.8 °C). In randomized order, participants donned full men's lacrosse equipment (helmet, shoulder/elbow pads, and gloves) in one trial while the other included no equipment. Participants completed a topography body scan to determine specific body surface area covered with equipment. Rectal temperature (Tre), heart rate (HR), and mean weighted skin temperature (Tsk) were measured throughout trials. Whole body sweat rate was assessed for trial comparisons. RESULTS: The equipment covered 32.62 ±â€¯2.53% body surface area in our participants. Post-exercise Tre was significantly greater with equipment (39.36 ±â€¯0.04 °C) compared to control (38.98 ±â€¯0.49 °C; p = .007). The overall rate of rise of Tre was significantly greater with equipment (0.043 ±â€¯0.015 °C·min-1) compared to control (0.031 ±â€¯0.008 °Cmin-1; p = .041). Regardless of time point, HR and Tsk were significantly elevated with equipment compared to control trial (p ≤ .026). Sweat rates were elevated with equipment (1.76 ±â€¯0.74 L·h-1) compared to shorts and t-shirt (1.13 ±â€¯0.26 L·h-1), but this difference was not significant (p = .058). CONCLUSIONS: Our data indicate impairments in heat dissipation and increased cardiovascular strain imposed by men's lacrosse equipment.


Assuntos
Temperatura Alta , Roupa de Proteção , Esportes com Raquete/fisiologia , Equipamentos Esportivos , Adulto , Regulação da Temperatura Corporal , Estudos Cross-Over , Ingestão de Energia , Frequência Cardíaca , Resposta ao Choque Térmico , Humanos , Masculino , Temperatura Cutânea , Sudorese , Adulto Jovem
9.
J Athl Train ; 56(2): 203-210, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33449078

RESUMO

CONTEXT: Hypohydration has been shown to alter neuromuscular function. However, the longevity of these impairments remains unclear. OBJECTIVE: To examine the effects of graded exercise-induced dehydration on neuromuscular control 24 hours after exercise-induced hypohydration. DESIGN: Crossover study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 23 men (age = 21 ± 2 years, height = 179.8 ± 6.4 cm, mass = 75.24 ± 7.93 kg, maximal oxygen uptake [VO2max] = 51.7 ± 5.5 mL·kg-1·min-1, body fat = 14.2% ± 4.6%). INTERVENTION(S): Participants completed 3 randomized exercise trials: euhydrated arrival plus fluid replacement (EUR), euhydrated arrival plus no fluid (EUD), and hypohydrated arrival plus no fluid (HYD) in hot conditions (ambient temperature = 35.2°C ± 0.6°C, relative humidity = 31.3% ± 2.5%). Each trial consisted of 180 minutes of exercise (six 30-minute cycles: 8 minutes at 40% VO2max; 8 minutes, 60% VO2max; 8 minutes, 40% VO2max; 6 minutes, passive rest) followed by 60 minutes of passive recovery. MAIN OUTCOME MEASURE(S): We used the Landing Error Scoring System and Balance Error Scoring System (BESS) to measure movement technique and postural control at pre-exercise, postexercise and passive rest (POSTEX), and 24 hours postexercise (POST24). Differences were assessed using separate mixed-design (trial × time) repeated-measures analyses of variance. RESULTS: The magnitude of hypohydration at POSTEX was different among EUR, EUD, and HYD trials (0.2% ± 1%, 3.5% ± 1%, and 5% ± 0.9%, respectively; P < .05). We observed no differences in Landing Error Scoring System scores at pre-exercise (2.9 ± 1.6, 3.0 ± 2.1, 3.0 ± 2.0), POSTEX (3.3 ± 1.5, 3.0 ± 2.0, 3.1 ± 1.9), or POST24 (3.3 ± 1.9, 3.2 ± 1.4, 3.3 ± 1.6) among the EUD, EUR, and HYD trials, respectively (P = .90). Hydration status did not affect BESS scores (P = .11), but BESS scores at POSTEX (10.4 ± 1.1) were greater than at POST24 (7.7 ± 0.9; P = .03). CONCLUSIONS: Whereas exercise-induced dehydration up to 5% body mass did not impair movement technique or postural control 24 hours after a prolonged bout of exercise in a hot environment, postural control was impaired at 60 minutes after prolonged exercise in the heat. Consideration of the length of recovery time between bouts of exercise in hot environments is warranted.

10.
J Sci Med Sport ; 24(8): 768-773, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33846088

RESUMO

OBJECTIVES: Determine whether five days of heat acclimation reduces cardiovascular and thermoregulatory strain during consecutive exercise-heat exposures on the sixth day in the heat. DESIGN: Pair-matched randomized control trial. METHODS: Twenty-four males completed two, 120min exercise sessions (Session 1, Session 2) in a single day before (Day 1) and after (Day 6) four additional days of exercise in either hot (HOT: 40°C, 40% relative humidity, n=16) or temperate (CON: 23°C, 25% relative humidity, n=8) environments. A mixed-methods heat acclimation approach was implemented. Day 2 consisted of 120min of moderate-high intensity treadmill exercise. Days 3-5 consisted of 90min of moderate-high intensity exercise, with HOT completing this in a hyperthermia clamped manner at rectal temperature ≥38.5°C, and CON<38.5°C. RESULTS: Session 1 end of exercise rectal temperature and heart rate were lower on Day 6 compared to Day 1 for HOT (p=0.012, p=0.003) but not CON (p=0.152, p=0.437). Session 2 end of exercise rectal temperature was not different between days for HOT (p=0.104) or CON (p=0.275). Session 2 end of exercise heart rate was lower on Day 6 compared to Day 1 for HOT (p=0.004) and CON (p=0.039). Session 1 sweat sensitivity was greater on Day 6 compared to Day 1 for HOT (p=0.039) but not CON (p=0.257). Sweat rate was unchanged for HOT and CON between days during Session 1 (p=0.184, p=0.962) and Session 2 (p=0.051, p=0.793), respectively. CONCLUSIONS: Five days of heat acclimation reduced cardiovascular strain but not thermoregulatory strain during the second, consecutive exercise-heat exposure. CLINICALTRIALS. GOV IDENTIFIER: NCT04053465.


Assuntos
Aclimatação , Exercício Físico/fisiologia , Resposta ao Choque Térmico , Temperatura Alta , Temperatura Corporal , Frequência Cardíaca , Humanos , Umidade , Masculino , Temperatura Cutânea , Sudorese , Fatores de Tempo , Adulto Jovem
11.
Artigo em Inglês | MEDLINE | ID: mdl-32092895

RESUMO

The combination of hyperthermia, dehydration, and strenuous exercise can result in severe reductions in kidney function, potentially leading to acute kidney injury (AKI). We sought to determine whether six days of heat acclimation (HA) mitigates the rise in clinical biomarkers of AKI during strenuous exercise in the heat. Twenty men completed two consecutive 2 h bouts of high-intensity exercise in either hot (n = 12, 40 °C, 40% relative humidity) or mild (n = 8, 24 °C, 21% relative humidity) environments before (PreHA) and after (PostHA) 4 days of 90-120 min of exercise per day in a hot or mild environment. Increased clinical biomarkers of AKI (CLINICAL) was defined as a serum creatinine increase ≥0.3 mg·dL-1 or estimated glomerular filtration rate (eGFR) reduction >25%. Creatinine similarly increased in the hot environment PreHA (0.35 ± 0.23 mg·dL-1) and PostHA (0.39 ± 0.20 mg·dL-1), with greater increases than the mild environment at both time points (0.11 ± 0.07 mg·dL-1, 0.08 ± 0.06 mg·dL-1, p ≤ 0.001), respectively. CLINICAL occurred in the hot environment PreHA (n = 9, 75%), with fewer participants with CLINICAL PostHA (n = 7, 58%, p = 0.007), and no participants in the mild environment with CLINICAL at either time point. Percent change in plasma volume was predictive of changes in serum creatinine PostHA and percent changes in eGFR both PreHA and PostHA. HA did not mitigate reductions in eGFR nor increases in serum creatinine during high-intensity exercise in the heat, although the number of participants with CLINICAL was reduced PostHA.


Assuntos
Aclimatação , Injúria Renal Aguda , Exercício Físico , Temperatura Alta , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/metabolismo , Adulto , Biomarcadores , Creatinina , Desidratação , Febre , Resposta ao Choque Térmico , Humanos , Masculino
12.
Nutrients ; 11(11)2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31703247

RESUMO

The purpose of this study was to examine the perception of thirst as a marker of hydration status following prolonged exercise in the heat. Twelve men (mean ± SD; age, 23 ± 4 y; body mass, 81.4 ± 9.9 kg; height, 182 ± 9 cm; body fat, 14.3% ± 4.7%) completed two 180 min bouts of exercise on a motorized treadmill in a hot environment (35.2 ± 0.6 °C; RH, 30.0 ± 5.4%), followed by a 60 min recovery period. Participants completed a euhydrated (EUH) and hypohydrated (HYPO) trial. During recovery, participants were randomly assigned to either fluid replacement (EUHFL and HYPOFL; 10 min ad libitum consumption) or no fluid replacement (EUHNF and HYPONF). Thirst was measured using both a nine-point scale and separate visual analog scales. The percent of body mass loss (%BML) was significantly greater immediately post exercise in HYPO (HYPOFL, 3.0% ± 1.2%; HYPONF, 2.6% ± 0.6%) compared to EUH (EUHFL, 0.2% ± 0.7%; EUHNF, 0.6% ± 0.5%) trials (p < 0.001). Following recovery, there were no differences in %BML between HYPOFL and HYPONF (p > 0.05) or between EUHFL and EUHNF (p > 0.05). Beginning at minute 5 during the recovery period, thirst perception was significantly greater in HYPONF than EUHFL, EUHNF, and HYPOFL (p < 0.05). A 10 min, ad libitum consumption of fluid post exercise when hypohydrated (%BML > 2%), negated differences in perception of thirst between euhydrated and hypohydrated trials. These results represent a limitation in the utility of thirst in guiding hydration practices.


Assuntos
Desidratação , Exercício Físico/fisiologia , Sede/fisiologia , Adulto , Biomarcadores , Desidratação/diagnóstico , Desidratação/fisiopatologia , Hidratação , Temperatura Alta , Humanos , Adulto Jovem
13.
J Sci Med Sport ; 22(10): 1084-1089, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31235386

RESUMO

OBJECTIVES: An exercise session in a hot environment may increase thermal strain during subsequent exercise sessions on the same and consecutive days. Therefore, this study was conducted to determine lasting physiological strain from moderate-high intensity, intermittent exercise in heat on subsequent exercise. DESIGN: Repeated measures laboratory study. METHODS: Seventeen healthy, recreationally active men (age: 22±3 y, maximal oxygen consumption: 54.6±5.3mLkg-1min-1) underwent two intermittent moderate-high intensity aerobic exercise sessions separated by 2h of rest one day, followed by one session 24h later in a 40°C, 40% relative humidity environment. Heart rate, rectal temperature, heat stress perception, and environmental symptoms were assessed. RESULTS: 100%, 35%, and 71% of participants completed the full exercise protocol during the first exercise session, second exercise session, and the following day, respectively. Exercising heart rate and rectal temperature were greater during the second exercise session (189±11bpm, 38.80±0.47°C) than the first identical exercise session (180±17bpm, p=0.004; 38.41±0.52°C, p=0.001), respectively. Immediate post-exercise heart rate, rectal temperature, thirst, thermal sensation, fatigue, and perceived exertion were similar among exercise sessions despite a shorter exercise duration during the second exercise session (93±27min, p=0.001) and the following day (113±12min, p=0.032) than the first exercise session (120±0min). CONCLUSIONS: Moderate-high-intensity intermittent exercise in the heat resulted in greater heat strain during a second exercise session the same day, and exercise the subsequent day.


Assuntos
Exercício Físico , Resposta ao Choque Térmico , Temperatura Alta , Adulto , Temperatura Corporal , Frequência Cardíaca , Humanos , Masculino , Consumo de Oxigênio , Fatores de Tempo , Adulto Jovem
14.
J Sci Med Sport ; 22(1): 117-122, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30554611

RESUMO

OBJECTIVES: To determine if intermittent exercise-heat exposures (IHE) every fifth day sustain heat acclimation (HA) adaptations 25 days after initial HA. DESIGN: Randomized control trial. METHODS: Sixteen non-heat acclimatized men heat acclimated during 10-11 days of exercise in the heat (40°C, 40% RH). A heat stress test (120min, 45% V˙O2peak) before (Pre HA) and after HA (Post HA) in similar hot conditions assessed HA status. Pair-matched participants were randomized into a control group (CON; n=7) that exercised in a temperate environment (24°C, 21%RH) or IHE group (n=9) that exercised in a hot environment (40°C, 40%RH) every fifth day for 25 days following HA (+25d) with out-of-laboratory exercise intensity and duration recorded. Both groups completed +25d in the hot condition. RESULTS: Both groups heat acclimated similarly (p>0.05) evidenced by lower heart rate (HR), thermoregulatory, physiological, and perceptual responses (perceived exertion, fatigue, thermal sensation) Pre HA vs. Post HA (p≤0.05). At +25d, post-exercise HR (p=0.01) and physiological strain index (p<0.05) but neither Tre (p=0.18) nor sweat rate (p=0.44) were lower in IHE vs. CON. In IHE only, post-exercise Tre and perceptual responses at Post HA and +25d were lower than Pre HA (p≤0.01). +25d post-exercise epinephrine was higher in CON vs. IHE (p=0.04). Exercise intensity during out-of-lab exercise and +25d post-exercise HR were correlated (r=-0.89, p=0.02) in IHE. CONCLUSIONS: Exercise-heat exposures every fifth day for 25 days and regular intense physical activity after HA sustained HR and Tre adaptations and reduced perceptual and physiological strain during exercise-heat stress ∼1 month later.


Assuntos
Aclimatação/fisiologia , Exercício Físico/fisiologia , Temperatura Alta , Frequência Cardíaca , Humanos , Masculino , Sudorese
15.
J Athl Train ; 52(1): 5-11, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28157403

RESUMO

CONTEXT: The presence of athletic trainers (ATs) in secondary schools to provide medical care is crucial, especially with the rise in sports participation and resulting high volume of injuries. Previous authors have investigated the level of AT services offered, but the differences in medical care offered between the public and private sectors have not been explored. OBJECTIVE: To compare the level of AT services in public and private secondary schools. DESIGN: Concurrent mixed-methods study. SETTING: Public and private secondary schools in the United States. PATIENTS OR OTHER PARTICIPANTS: A total of 10 553 secondary schools responded to the survey (8509 public, 2044 private). MAIN OUTCOME MEASURE(S): School administrators responded to the survey via telephone or e-mail. Descriptive statistics depict national data. Open-ended questions were evaluated through content analysis. RESULTS: A greater percentage of public secondary schools than private secondary schools hired ATs. Public secondary schools provided a higher percentage of full-time, part-time, and clinic AT services than private secondary schools. Only per diem AT services were more frequent in the private sector. Regardless of the extent of services, reasons for not employing an AT were similar between sectors. Common barriers were budget, school size, and lack of awareness of the role of an AT. Unique to the public sector, remote location was identified as a challenge faced by some administrators. CONCLUSIONS: Both public and private secondary schools lacked ATs, but higher percentages of total AT services and full-time services were available in the public sector. Despite differences in AT services, both settings provided a similar number of student-athletes with access to medical care. Barriers to hiring ATs were comparable between public and private secondary schools; however, remote location was a unique challenge for the public sector.


Assuntos
Serviços de Saúde Escolar/estatística & dados numéricos , Instituições Acadêmicas/estatística & dados numéricos , Medicina Esportiva/estatística & dados numéricos , Pessoal Administrativo , Atletas/estatística & dados numéricos , Orçamentos , Emprego/estatística & dados numéricos , Acessibilidade aos Serviços de Saúde/economia , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Humanos , Setor Privado/economia , Setor Privado/estatística & dados numéricos , Setor Público/economia , Setor Público/estatística & dados numéricos , Serviços de Saúde Escolar/economia , Instituições Acadêmicas/economia , Esportes/economia , Esportes/estatística & dados numéricos , Medicina Esportiva/economia , Estudantes/estatística & dados numéricos , Inquéritos e Questionários , Estados Unidos
16.
J Sci Med Sport ; 20(9): 861-866, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28162913

RESUMO

Long-term implementation of preventive training programs (PTP) in youth sport requires coach involvement. However, the optimal training of coaches to effectively implement a PTP remains unknown. It is also unknown if the benefits of PTP can be enhanced with multiple sport seasons of exposure. OBJECTIVES: To evaluate the influence of prior PTP exposure on movement technique in youth soccer players after completing a coach-led PTP. DESIGN: Cluster-randomized controlled trial. METHODS: Twelve youth soccer teams (n=89; age range 8-14 years) were divided into groups with (Experience (EXP); 6 teams [n=18 females, n=25 males]) and without (Novice (NOV); 6 teams [n=30 females, n=16 males]) previous professional-led PTP experience. The coaches and players of the EXP teams were exposed to an eight-week professional-led PTP before the coach-led PTP. EXP and NOV coaches attended the educational workshop prior to implementing the coach-led PTP. The Landing Error Scoring System (LESS) was used to evaluate movement technique. RESULTS: Both groups improved LESS scores over time (mean difference±SD [post-pre]=-0.8±0.2, 95%CI [-1.2, -0.4], p=0.0001). Of the 64 participants classified as high risk for injury (LESS ≥5) prior to PTP implementation, a greater proportion of EXP (n=14) compared to NOV (n=7) participants changed risk classification from high to low (LESSΔ≥1 and LESS <5; p=0.03). CONCLUSIONS: Our PTP enhanced movement technique regardless of PTP experience, but the benefits of the PTP impacted a proportionally greater number of players with previous PTP experience supporting continued PTP implementation. Coaches effectively implemented an exercise-based PTP after attending a training workshop regardless of previous PTP experience.


Assuntos
Traumatismos em Atletas/prevenção & controle , Movimento/fisiologia , Condicionamento Físico Humano/métodos , Futebol/lesões , Adolescente , Atletas , Criança , Feminino , Humanos , Masculino , Tutoria , Futebol/fisiologia
17.
J Athl Train ; 52(4): 377-383, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28430550

RESUMO

CONTEXT: Recent case reports on malignant hyperthermia (MH)-like syndrome in physically active populations indicate potential associations among MH, exertional heat stroke (EHS), and exertional rhabdomyolysis (ER). However, an expert consensus for clinicians working with these populations is lacking. OBJECTIVE: To provide current expert consensus on the (1) definition of MH; (2) history, etiology, and pathophysiology of MH; (3) epidemiology of MH; (4) association of MH with EHS and ER; (5) identification of an MH-like syndrome; (6) recommendations for acute management of an MH-like syndrome; (7) special considerations for physically active populations; and (8) future directions for research. SETTING: An interassociation task force was formed by experts in athletic training, exercise science, anesthesiology, and emergency medicine. The "Round Table on Malignant Hyperthermia in Physically Active Populations" was convened at the University of Connecticut, Storrs, September 17-18, 2015. CONCLUSIONS: Clinicians should consider an MH-like syndrome when a diagnosis of EHS or ER cannot be fully explained by clinical signs and symptoms presented by a patient or when recurrent episodes of EHS or ER (or both) are unexplained. Further research is required to elucidate the genetic and pathophysiological links among MH, EHS, and ER.


Assuntos
Exercício Físico/fisiologia , Hipertermia Maligna/diagnóstico , Rabdomiólise/diagnóstico , Consenso , Diagnóstico Diferencial , Golpe de Calor/diagnóstico , Golpe de Calor/etiologia , Golpe de Calor/terapia , Humanos , Hipertermia Maligna/etiologia , Hipertermia Maligna/terapia , Recidiva , Rabdomiólise/etiologia , Rabdomiólise/terapia , Síndrome
18.
J Athl Train ; 50(2): 156-62, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25689559

RESUMO

CONTEXT: Authors of the most recent study of athletic training (AT) services have suggested that only 42% of secondary schools have access to athletic trainers. However, this study was limited by a small sample size and was conducted more than 10 years ago. OBJECTIVE: To determine current AT services in public secondary schools. DESIGN: Cross-sectional study. SETTING: Public secondary schools in the United States. PATIENTS OR OTHER PARTICIPANTS: A total of 8509 (57%) of 14,951 secondary schools from all 50 states and Washington, DC, responded to the survey. MAIN OUTCOME MEASURE(S): Data on AT services were collected for individual states, National Athletic Trainers' Association districts, and the nation. RESULTS: Of the 8509 schools that responded, 70% (n = 5930) had AT services, including full-time (n = 3145, 37%), part-time (n = 2619, 31%), and per diem (n = 199, 2%) AT services, and 27% (n = 2299) had AT services from a hospital or physical therapy clinic. A total of 4075 of 8509 schools (48%) provided coverage at all sports practices. Eighty-six percent (2,394,284/2,787,595) of athletes had access to AT services. CONCLUSIONS: Since the last national survey, access to AT services increased such that 70% of respondent public secondary schools provided athletic trainers at sports games or practices. Approximately one-third of all public secondary schools had full-time athletic trainers. This number must increase further to provide appropriate medical coverage at athletic practices and games for secondary school athletes.


Assuntos
Exercício Físico , Serviços de Saúde Escolar , Esportes , Adulto , Benchmarking , Estudos Transversais , Educação Profissionalizante/estatística & dados numéricos , Feminino , Humanos , Masculino , Avaliação de Resultados em Cuidados de Saúde , Setor Público , Serviços de Saúde Escolar/organização & administração , Serviços de Saúde Escolar/estatística & dados numéricos , Instituições Acadêmicas/estatística & dados numéricos , Esportes/educação , Esportes/normas , Esportes/estatística & dados numéricos , Estados Unidos , Recursos Humanos
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