scholarly journals Kajian Pengaruh Heat Stress terhadap Beban Kerja Fisik Berat pada Kegiatan Lapangan

2021 ◽  
Vol 1 (1) ◽  
pp. 167-174
Author(s):  
Caecilia Sri Wahyuning ◽  
Diah Budi Laksemi
Keyword(s):  
Heat Stress ◽  
Energy Expenditure ◽  
Sweat Rate

Penelitian ini merupakan studi pendahuluan terhadap pengaruh tekanan panas terhadap beban kerja berat pada kegiatan lapangan, mengingat Indonesia sebagai negara tropis memiliki suhu dan kelembaban udara tinggi. Cuaca panas, yang dapat menyebabkan heat stress, merupakan beban bagi tubuh dan semakin berat pada aktivitas fisik berat. Eksperimen dilakukan terhadap 20 partisipan (10 orang pria, 10 orang wanita) yang melakukan pekerjaan dengan intensitas kerja tinggi selama 30 menit di lapangan dengan iklim ekstrim. Beban kerja dilihat berdasarkan denyut jantung dan berat badan untuk melihat energy expenditure, intensitas kerja, dan sweat rate. Hasil pengukuran menunjukkan beban kerja pada eksperimen ini termasuk dalam kategori tinggi/berat. Iklim lapangan diukur berdasarkan indeks WBGT, dan hasil pengukuran menunjukkan bahwa indeks WBGT selama eksperimen adalah  31°C (87.9°F), termasuk dalam kategori berisiko tekanan panas sangat tinggi. Hasil penelitian menunjukkan bahwa iklim tidak berpengaruh terhadap energy expenditure, akan tetapi berpengaruh terhadap energy expenditure pada partisipan wanita (p<0.05). Iklim juga berpengaruh terhadap intensitas kerja (p<0.05), sedangkan sweat rate tidak dapat digunakan untuk menghitung beban kerja karena waktu eksprimen tidak cukup meningkatkan panas tubuh dan hanya berdasarkan berat badan. Penelusuran lebih seksama terhadap  model estimasi expenditure yang digunakan dalam sebuah eksperimen diperlukan agar sesuai dengan karakteristik pekerjaan.

scholarly journals Heat Stress Reduces Metabolic Rate While Increasing Respiratory Exchange Ratio in Growing Pigs

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 215
Author(s):  
Dane W. Fausnacht ◽  
Kellie A. Kroscher ◽  
Ryan P. McMillan ◽  
Luciane S. Martello ◽  
Lance H. Baumgard ◽  
...  
Keyword(s):  
Heat Stress ◽  
Energy Expenditure ◽  
Metabolic Rate ◽  
Respiratory Exchange Ratio ◽  
Muscle Growth ◽  
Growing Pigs ◽  
Metabolic Phenotype ◽  
Substrate Regulation ◽  
Enclosed Chamber ◽  
Muscle Biopsies

Heat stress (HS) diminishes animal production, reducing muscle growth and increasing adiposity, especially in swine. Excess heat creates a metabolic phenotype with limited lipid oxidation that relies on aerobic and anaerobic glycolysis as a predominant means of energy production, potentially reducing metabolic rate. To evaluate the effects of HS on substrate utilization and energy expenditure, crossbred barrows (15.2 ± 2.4 kg) were acclimatized for 5 days (22 °C), then treated with 5 days of TN (thermal neutral, 22 °C, n = 8) or HS (35 °C, n = 8). Pigs were fed ad libitum and monitored for respiratory rate (RR) and rectal temperature. Daily energy expenditure (DEE) and respiratory exchange ratio (RER, CO2:O2) were evaluated fasted in an enclosed chamber through indirect calorimetry. Muscle biopsies were obtained from the longissimus dorsi pre/post. HS increased temperature (39.2 ± 0.1 vs. 39.6 ± 0.1 °C, p < 0.01) and RER (0.91 ± 0.02 vs. 1.02 ± 0.02 VCO2:VO2, p < 0.01), but decreased DEE/BW (68.8 ± 1.7 vs. 49.7 ± 4.8 kcal/day/kg, p < 0.01) relative to TN. Weight gain (p = 0.80) and feed intake (p = 0.84) did not differ between HS and TN groups. HS decreased muscle metabolic flexibility (~33%, p = 0.01), but increased leucine oxidation (~35%, p = 0.02) compared to baseline values. These data demonstrate that HS disrupts substrate regulation and energy expenditure in growing pigs.

Effect of season on thermoregulatory responses and energy expenditure of goats on semi-arid range in India

2002 ◽  
Vol 139 (1) ◽  
pp. 87-93 ◽  
Author(s):  
A. K. SHINDE ◽  
RAGHAVENDRA BHATTA ◽  
S. K. SANKHYAN ◽  
D. L. VERMA
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Solar Radiation ◽  
Energy Expenditure ◽  
Arid Regions ◽  
Physiological Responses ◽  
Face Mask ◽  
Mean Value ◽  
The Mean ◽  
Semi Arid

A study of the physiological responses and energy expenditure of goats was carried out from June 1999 to May 2000 by conducting two experiments: one on bucks maintained on stall feeding in autumn 1999 (Expt 1) followed by year-round grazing on native ranges over three seasons: monsoon, winter and summer (Expt 2). Physiological responses and energy expenditure (EE) measurements of housed and grazing goats were recorded at 06.00 h and 14.00 h for 5 consecutive days in each season. Goats were fixed with a face mask and meteorological balloon for collection of expired air and measurement of EE. Respiration rate (RR) at 06.00 h was similar in all seasons (14 respiration/min) except in the monsoon, where a significantly (P<0.05) higher value (26 respiration/min) was recorded. At 14.00 h, RR was higher in monsoon and summer (81 and 91 respiration/min) than in winter (52 respiration/min). Irrespective of the season, heart rate (HR) was higher at 14.00 h (86 beat/min) than at 06.00 h (64 beat/min). The rise of rectal temperature (RT) from morning (06.00 h) to peak daily temperature (14.00 h) was 0.9 °C in housed goats in autumn and 1.0, 2.1 and 2.0 °C in grazing goats during monsoon, winter and summer, respectively. The mean value was 1.7 °C. Skin temperature (ST) was lowest in winter (30.1 °C) and highest at 14.00 h in summer (40.3 °C). Energy expenditure of goats at 06.00 h was 32.7 W in winter and significantly (P<0.05) increased to 52.0 W in summer and 107.8 W in monsoon. At 14.00 h, EE was 140.2 W in winter and increased to 389.0 W and 391.3 W respectively in monsoon and summer. It is concluded that monsoon and summer are both stressful seasons in semi-arid regions. Animals should be protected from direct solar radiation during the hottest hours of the day to ameliorate the effect of heat stress.

Thermoregulatory, cardiovascular, and psychophysical response to alcohol in men in 40 degrees C water

1992 ◽  
Vol 72 (6) ◽  
pp. 2099-2107 ◽  
Author(s):  
T. G. Allison ◽  
W. E. Reger
Keyword(s):  
Heat Stress ◽  
Sweat Rate ◽  
Cardiovascular Response ◽  
Water Immersion ◽  
Rate Pressure Product ◽  
Esophageal Temperature ◽  
Healthy Men ◽  
Cardiovascular Stress ◽  
Rate Of Increase ◽  
Normal Relationship

The goals of the study were to test the hypotheses that ethyl alcohol (ETOH) in low-to-moderate doses would alter thermo-regulation and/or disrupt the normal relationship between physiological and psychophysical indexes of heat stress during 40 degrees C water immersion and to characterize the cardiovascular response to the combined stimuli of heat, water immersion, and ETOH. Six healthy men underwent three trials of 21 min of immersion in water at 40.0 +/- 0.1 degrees C after consuming 0, 0.27, or 0.54 g ETOH/kg. Esophageal temperature (Tes) rose by approximately 1.0 degrees C during immersion for each trial. Per unit of Tes rise, changes during immersion in skin temperature, sweat rate, heart rate, systolic and diastolic blood pressure, and psychophysical assessments of comfort and overheating did not differ significantly by trial. Across trials, there was an apparent threshold for activation of thermoregulatory responses at an approximately 0.5 degrees C increase in Tes occurring after approximately 9 min of immersion. This threshold was identified psychophysically by increased ratings of overheating and decreased comfort. Above the threshold, there was an attenuation of the rate of increase of Tes. Cardiovascular stress was mild (rate-pressure product approximately 12,000) and not significantly increased by ETOH. Hypotension and tachycardia when subjects stood to exit the tub were observed. The data suggest that ETOH at the doses administered does not affect thermoregulatory, cardiovascular, or psychophysical indexes of heat stress during 40 degrees C water immersion.

Heat acclimation, aerobic fitness, and hydration effects on tolerance during uncompensable heat stress

1998 ◽  
Vol 84 (5) ◽  
pp. 1731-1739 ◽  
Author(s):  
Stephen S. Cheung ◽  
Tom M. McLellan
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Aerobic Fitness ◽  
Protective Clothing ◽  
Sweat Rate ◽  
Heat Acclimation ◽  
Short Term ◽  
Chemical Protective Clothing ◽  
Uncompensable Heat Stress ◽  
C 30

—The purpose of the present study was to determine the separate and combined effects of aerobic fitness, short-term heat acclimation, and hypohydration on tolerance during light exercise while wearing nuclear, biological, and chemical protective clothing in the heat (40°C, 30% relative humidity). Men who were moderately fit [(MF); <50 ml ⋅ kg−1 ⋅ min−1maximal O2 consumption; n = 7] and highly fit [(HF); >55 ml ⋅ kg−1 ⋅ min−1maximal O2 consumption; n = 8] were tested while they were euhydrated or hypohydrated by ∼2.5% of body mass through exercise and fluid restriction the day preceding the trials. Tests were conducted before and after 2 wk of daily heat acclimation (1-h treadmill exercise at 40°C, 30% relative humidity, while wearing the nuclear, biological, and chemical protective clothing). Heat acclimation increased sweat rate and decreased skin temperature and rectal temperature (Tre) in HF subjects but had no effect on tolerance time (TT). MF subjects increased sweat rate but did not alter heart rate, Tre, or TT. In both MF and HF groups, hypohydration significantly increased Tre and heart rate and decreased the respiratory exchange ratio and the TT regardless of acclimation state. Overall, the rate of rise of skin temperature was less, while ΔTre, the rate of rise of Tre, and the TT were greater in HF than in MF subjects. It was concluded that exercise-heat tolerance in this uncompensable heat-stress environment is not influenced by short-term heat acclimation but is significantly improved by long-term aerobic fitness.

Forearm cutaneous vascular and sudomotor responses to whole body passive heat stress in young smokers

2015 ◽  
Vol 309 (1) ◽  
pp. R36-R42 ◽  
Author(s):  
Nicole E. Moyen ◽  
Hannah M. Anderson ◽  
Jenna M. Burchfield ◽  
Matthew A. Tucker ◽  
Melina A. Gonzalez ◽  
...  
Keyword(s):  
Heat Stress ◽  
Sweat Gland ◽  
Sweat Rate ◽  
Whole Body ◽  
Mean Body Temperature ◽  
Doppler Flowmetry ◽  
Cutaneous Vasodilation ◽  
Local Sweat Rate ◽  
Vasomotor Activity ◽  
Young Smokers

The purpose of this study was to compare smokers and nonsmokers' sudomotor and cutaneous vascular responses to whole body passive heat stress. Nine regularly smoking (SMK: 29 ± 9 yr; 10 ± 6 cigarettes/day) and 13 nonsmoking (N-SMK: 27 ± 8 yr) males were passively heated until core temperature (TC) increased 1.5°C from baseline. Forearm local sweat rate (LSR) via ventilated capsule, sweat gland activation (SGA), sweat gland output (SGO), and cutaneous vasomotor activity via laser-Doppler flowmetry (CVC) were measured as mean body temperature increased (ΔTb) during passive heating using a water-perfused suit. Compared with N-SMK, SMK had a smaller ΔTb at the onset of sweating (0.52 ± 0.19 vs. 0.35 ± 0.14°C, respectively; P = 0.03) and cutaneous vasodilation (0.61 ± 0.21 vs. 0.31 ± 0.12°C, respectively; P < 0.01). Increases in LSR and CVC per °C ΔTb (i.e., sensitivity) were similar in N-SMK and SMK (LSR: 0.63 ± 0.21 vs. 0.60 ± 0.40 Δmg/cm2/min/°C ΔTb, respectively, P = 0.81; CVC: 82.5 ± 46.2 vs. 58.9 ± 23.3 Δ%max/°C ΔTb, respectively; P = 0.19). However, the plateau in LSR during whole body heating was higher in N-SMK vs. SMK (1.00 ± 0.13 vs. 0.79 ± 0.26 mg·cm−2·min−1; P = 0.03), which was likely a result of higher SGO (8.94 ± 3.99 vs. 5.94 ± 3.49 μg·gland−1·min−1, respectively; P = 0.08) and not number of SGA (104 ± 7 vs. 121 ± 9 glands/cm2, respectively; P = 0.58). During whole body passive heat stress, smokers had an earlier onset for forearm sweating and cutaneous vasodilation, but a lower local sweat rate that was likely due to lower sweat output per gland. These data provide insight into local (i.e., forearm) thermoregulatory responses of young smokers during uncompensatory whole body passive heat stress.

Active cutaneous vasodilation in resting humans during mild heat stress

2005 ◽  
Vol 98 (3) ◽  
pp. 829-837 ◽  
Author(s):  
Yoshi-Ichiro Kamijo ◽  
Kichang Lee ◽  
Gary W. Mack
Keyword(s):  
Blood Flow ◽  
Heat Stress ◽  
Skin Temperature ◽  
Skin Blood Flow ◽  
Sweat Rate ◽  
Mean Skin Temperature ◽  
Local Skin ◽  
Mild Heat ◽  
Normal Core ◽  
Local Sweat Rate

The role of skin temperature in reflex control of the active cutaneous vasodilator system was examined in six subjects during mild graded heat stress imposed by perfusing water at 34, 36, 38, and 40°C through a tube-lined garment. Skin sympathetic nerve activity (SSNA) was recorded from the peroneal nerve with microneurography. While monitoring esophageal, mean skin, and local skin temperatures, we recorded skin blood flow at bretylium-treated and untreated skin sites by using laser-Doppler velocimetry and local sweat rate by using capacitance hygrometry on the dorsal foot. Cutaneous vascular conductance (CVC) was calculated by dividing skin blood flow by mean arterial pressure. Mild heat stress increased mean skin temperature by 0.2 or 0.3°C every stage, but esophageal and local skin temperature did not change during the first three stages. CVC at the bretylium tosylate-treated site (CVCBT) and sweat expulsion number increased at 38 and 40°C compared with 34°C ( P < 0.05); however, CVC at the untreated site did not change. SSNA increased at 40°C ( P < 0.05, different from 34°C). However, SSNA burst amplitude increased ( P < 0.05), whereas SSNA burst duration decreased ( P < 0.05), at the same time as we observed the increase in CVCBT and sweat expulsion number. These data support the hypothesis that the active vasodilator system is activated by changes in mean skin temperature, even at normal core temperature, and illustrate the intricate competition between active vasodilator and the vasoconstrictor system for control of skin blood flow during mild heat stress.

Consistency Assessment of Heat Stress Monitoring of Outdoor Workers Using Sweat Rate Measurement and Wet Bulb Globe Temperature WBGT in Arid and Semi-Arid Climates

Health Scope ◽  
2018 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Hamidreza Heidari ◽  
Farideh Golbabaei ◽  
Aliakbar Shamsipour ◽  
Abbas Rahimi Forushani ◽  
Abbasali Gaeini
Keyword(s):  
Heat Stress ◽  
Sweat Rate ◽  
Rate Measurement ◽  
Stress Monitoring ◽  
Wet Bulb Globe Temperature ◽  
Outdoor Workers ◽  
Globe Temperature ◽  
Semi Arid

Effect of vapor pressure on physiologic strain and body heat storage

1963 ◽  
Vol 18 (4) ◽  
pp. 808-811 ◽  
Author(s):  
John F. Hall
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Vapor Pressure ◽  
Heat Storage ◽  
Sweat Rate ◽  
Human Subjects ◽  
Vapor Pressures ◽  
Physiologic Responses ◽  
Male Subjects ◽  
Body Heat

Physiologic strain, in terms of body heat storage, and other physiologic responses were measured and compared in two series of heat stress experiments performed on human subjects exposed to different ambient vapor pressures. One group of 75 experiments conducted on 5 healthy nonacclimatized male subjects exposed 5 times each to 38, 54, and 71 C at 10 mm Hg vapor pressure was compared with a series of 81 experiments performed on 10 similar subjects exposed 1–6 times each to 38, 41, and 54 C at 20 mm Hg vapor pressure. Subjects were sitting and wore 1.0 clo insulation. The data show relation between body heat storage and a) the modified Craig index of physiologic strain; b) over-all sweat rate; c) evaporative rate; d) sweat-evaporative ratio; e) mean skin and rectal temperatures; and f) change of heart rate at the respective vapor pressure levels. Statistically significant correlation between sweat-evaporative ratio and over-all sweat rate with body heat storage is shown. Use of the over-all sweat response as a physiologic strain index is suggested. Submitted on August 14, 1962

Can gender differences during exercise-heat stress be assessed by the physiological strain index?

1999 ◽  
Vol 276 (6) ◽  
pp. R1798-R1804 ◽  
Author(s):  
Daniel S. Moran ◽  
Yair Shapiro ◽  
Arie Laor ◽  
Sharona Izraeli ◽  
Kent B. Pandolf
Keyword(s):  
Gender Differences ◽  
Heat Stress ◽  
Sweat Rate ◽  
Physiological Strain ◽  
Strain Index ◽  
Wide Acceptance ◽  
Physiological Strain Index ◽  
Lower Strain ◽  
And Gender ◽  
C 50

A physiological strain index (PSI) based on rectal temperature (Tre) and heart rate (HR) was recently suggested to evaluate exercise-heat stress. The purpose of this study was to evaluate PSI for gender differences under various combinations of exercise intensity and climate. Two groups of eight men each were formed according to maximal rate of O2 consumption (V˙o 2 max). The first group of men (M) was matched to a group of nine women (W) with similar ( P > 0.001)V˙o 2 max (46.1 ± 2.0 and 43.6 ± 2.9 ml ⋅ kg−1 ⋅ min−1, respectively). The second group of men (MF) was significantly ( P < 0.001) more fit than M or W with V˙o 2 max of 59.1 ± 1.8 ml ⋅ kg−1 ⋅ min−1. Subjects completed a matrix of nine experimental combinations consisting of three different exercise intensities for 60 min [low, moderate, and high (300, 500, and 650 W, respectively)] each at three climates {comfortable, hot wet, and hot dry [20°C 50% relative humidity (RH), 35°C 70% RH, and 40°C 35% RH, respectively]}. No significant differences ( P > 0.05) were found between matched genders (M and W) at the same exposure for sweat rate, relativeV˙o 2 max(%V˙o 2 max), and PSI. However, MF had significantly ( P < 0.05) lower strain than M and W as reflected by %V˙o 2 max and PSI. In summary, PSI applicability was extended for exercise-heat stress and gender. This index continues to show potential for wide acceptance and application.

Sweating sensitivity and capacity of women in relation to age

1982 ◽  
Vol 53 (3) ◽  
pp. 671-676 ◽  
Author(s):  
B. L. Drinkwater ◽  
J. F. Bedi ◽  
A. B. Loucks ◽  
S. Roche ◽  
S. M. Horvath
Keyword(s):  
Heat Stress ◽  
Older Women ◽  
Forearm Blood Flow ◽  
Thermal Environment ◽  
Sweat Rate ◽  
Age Groups ◽  
Whole Body ◽  
Volume Changes ◽  
Younger Women ◽  
Significant Difference

Ten postmenopausal and ten younger women rested for 2 h in a 40 degrees C, 22.2-Torr vapor pressure environment. Sweating response was monitored by resistance hygrometry for onset, a platform balance for whole-body sweat rate, and five individual capsules for regional sweat rate. Other variables measured included forearm blood flow, heart rate (HR), mean skin (Tsk) and rectal (Tre) temperatures, sweat electrolytes (Na+ and K+), oxygen uptake, and plasma volume changes. Preliminary tests included maximal aerobic power (VO2max) and percent body fat. Heat stress did not elicit any significant differences in sweating response between age groups. Indices of heat strain, Tre and HR, were also similar for both groups. The only significant difference between younger and older women was a higher Na+ concentration in the forearm sweat of postmenopausal women. No thermoregulatory responses were related to age, but both sweat rate (r = 0.48) and peak Tsk (r = -0.43) were related to VO2max. For healthy, active, older women aging did not diminish the functional capacity of the sweating mechanism to cope with heat stress while resting in this specific thermal environment.

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