Influence of environmental factors on sweating rate of sedentary subjects

Results of a comparative study on the influence of various thermal indices on the sweating rate of sedentary subjects have been reported in this paper. Superiority of dry-bulb temperature of air over other indices for rough assessment of water requirement in relatively dry heat has been demonstrated, and a simple prediction chart for the same has been worked out. The results have thus been found to lend support to the idea that sweating rate alone cannot serve as an index of comfort. Limitations of such field trials have also been discusse

Transient post-exercise hyper-perspiration of forehead area

Information about sweating responses during exercise recovery is insufficient and mostly controversial. In the present study, particular attention is given to sweating behavior at forehead area immediately after exercise. Simultaneous changes of some underlying factors are also addressed. Eight healthy young males (27.4±0.8 years old) volunteered for the study. They performed a constant work rate exercise (60 rpm at 50% of individual work load for VO2 peak) for 30 min. Sweating from the forehead area was measured by the weight gain of a covered filter paper disk. Simultaneous variations in tympanic temperature, heart rate and mean arterial pressure were obtained. Plasma concentrations for sodium, vasopressin, adrenalin and noradrenalin were also determined. Sweating rate increased up to the first sample taken immediately after exercise cessation (P < 0.05). All other variables measured increased during exercise and with exception of noradrenalin, which was maintained high. Other variables, on the whole, decreased during recovery period. At exercise, off-transient coincident with overshoot in sweating rate, tympanic temperature, noradrenalin and vasopressin were subject to a non significant elevation. These results suggest that, sweating from forehead area is still subject to increase at exercise off-transient. The effects of relevant factors studied here are contradictory and could not justify the increase seen in sweating at off-transient. More studies are required to elucidate the causative factor(s).Key words: Exercise off-transient, recovery, sweating rate, forehead

Development of mathematical models of environmental physiology

Selected articles concerned with mathematical or simulation models of human thermoregulation are presented. The articles presented include: (1) development and use of simulation models in medicine, (2) model of cardio-vascular adjustments during exercise, (3) effective temperature scale based on simple model of human physiological regulatory response, (4) behavioral approach to thermoregulatory set point during exercise, and (5) importance of skin temperature in sweat regulation

The Physiology of Thermoregulation in Exercise: A Brief Review

During physical exercise, the production of heat in the working skeletal muscles increases, imposing heat stress on the body. Thermoregulatory mechanisms induce adjustments of cutaneous vascular conductance and thus skin blood flow (SkBF), sweating rate, and increased cardiac output to achieve thermal homeostasis. The response depends on the intensity, type, duration of exercise, and environmental temperature: during extreme exercise in a hot environment SkBF can attain up to 7 L/min compared to 300 mL/min at rest whereas the sweating rate can reach as high as 4 L/h. Due to opposing non-thermal reflexes, the thermoregulatory response of SkBF during exercise differs from that at rest: the threshold to induce vasodilation in the skin is shifted to higher body core temperature and the sensitivity of the “SkBF to-core temperature” slope is altered. Regular training induces better adaptations to physical stress which enable sportsmen to eliminate additional heat more optimally. The review emphasizes physiological mechanisms involved in thermoregulation during exercise and exposes some thoughts regarding the estimation t of the core temperature in humans, as well as some new approaches for an up-to-date assessment of parameters important for appropriate heat dissipation thereby maintaining core temperature

Heat loss efficiency and thermoregulation responses of Nellore cows

Abstract: Nellore cattle is well adapted to tropical environmental conditions with good thermoregulatory characteristics. However, knowledge related to body temperature regulation and acclimatization mechanisms are still scarce. This investigation aimed to understand the heat loss efficiency and thermoregulation responses of Nellore cows in tropical climate conditions. In this study was used 16 healthy purebred Nellore cows classified by heat loss in efficient and non-efficient using the vaginal temperature continuously monitored by data-loggers. The rectal, tail and ocular temperatures, sweating rate and respiratory frequency were also measured to understand the thermoregulatory responses and correlate to previous classification. In our findings, were noticed that according to heat loss classification the nonefficient cows showed greater amplitude of temperature variation. The body temperature increased from 12:00 PM to 19:00 PM with gradual decreased from 19:00 PM to 07:00 AM, reaching the peak in both groups at around 16:00 PM. In addition, the efficient cows presented higher sweating rate than non-efficient that presented higher rectal temperature, therefore the reduction of body temperature by improving evaporative mechanisms is a good trait of acclimatization to heat. No statistical difference was observed for the other physiological variables between groups. In conclusion, the methodology to classify the cows by heat loss using vaginal data loggers allowed us to distinguish Nellore cows according to their body temperature regulation, being feasible and reproducible. Furthermore, the efficiency to heat loss of this bred was mainly associated with sweating capacity

Sweat Rate Monitoring During Maximal Exercise in Healthy Soccer Players: A Close Relationship with Anaerobic Threshold

Purpose: Sweating is a homeostatic phenomenon regulated by both thermal and non-thermal factors during exercise. There are no evidences whether anaerobic metabolism induced during isotonic maximal exercise can modify sweating rate. Aim of the study was to investigate the relationship between sweating and the anaerobic threshold (AT). Methods: The sweat rate in thirteen soccer players was measured by a sensor providing a continuous monitoring of sweating, whereas the anaerobic threshold was assessed with ergospirometry during maximal isotonic stress test. During stress test, cardio respiratory, metabolic and galvanic skin response (GSR) were also monitored. Results: At AT, stroke volume, heart rate and systolic blood pressure significantly increased (p<0.001), as well as GSR (p=0.04). Sweat rate abruptly increased at AT compared with rest (p<0.001). AT-to-rest changes in sweating rate were associated with concomitant changes in VO2 max (r=0.82, p<0.001), heart rate (r=0.73, p=0.04) and GSR (r=0.79, p=0.001). Conclusion: We suggest that aerobic-to-anaerobic switch is associated with a sudden increase in sweating likely induced by sympathetic activation. Considering the role of hydration in preserving the health status and optimizing the physical performance, we believe that this finding may have relevant practical implication in particular in soccer, which is characterized by an alternation of aerobic and anaerobic phases

Study of Sweating Rate and Microscopic Anatomy of Some Breeds Bulls Sweat Glands in Different Body Parts

The study aimed to analyze the sweating rate and the microscopic anatomy of sweat glands of many breed bulls in different parts of the body. Ten bulls of 5 breeds (Simmental, Limousin, Crossed Ongole breed (PO), SimPO (Crossed between Simmental and PO), and LimPO (Crossed between Limousine and PO) in Authorized Slaughterhouse of Malang and Surabaya city were used during the study. Two bulls of each breed were observed for the sweating rate using a Cobalt Chloride Disk (CCD). The skin samples of four places in the legs and back of the animal were taken to be observed under a light microscope in the laboratory of Biosains of Universitas Brawijaya.  The result showed that for all breeds, the sweating rates in the legs were higher (P<0.05) than in the back.  It was observed that the sweat glands of the legs had tubular, but the back part is in irregular shapes. Based on the study result it is suggested to measure the sweating rate in the back part of the animal body

Heat Tolerance Coefficient Dan Sweating Rate Pada Bangsa Sapi Peranakan Ongole (PO) Dan Persilangan Dengan Simmental (Simpo) Di RPH Gadang Kota Malang

Persilangan bangsa sapi Bos indicus (Peranakan Ongole) dengan bangsa sapi Bos taurus (Simmental) bertujuan untuk menghasilkan sapi potong yang memiliki reproduksi dan pertumbuhan yang bagus. Persilangan diantara kedua bangsa sapi tersebut diharapkan dapat meningkatkan produktifitas sapi dengan menggabungkan sifat-sifat unggul dari kedua bangsa sapi. Peningkatan produksi sapi potong dapat dilakukan dengan dua cara yaitu pendekatan kuantitatif (peningkatan populasi) dan kualitatif (produksi per unit ternak) sebagai salah satu alternatif dalam pemecahan masalah kekurangan pasokan daging sapi di Indonesia. maka dari itu penelitian ini dilakukan untuk mengetahui pebedaan HTC dan Sweating rate antara bangsa sapi Peranakan Ongole (PO) dan Persilangan dengan Simmental (Simpo). HTC merupakan ketahanan ternak terhadap panas di sekitarnya sedangkan sweating rate merupakan tingkat keluarnya keringat atau laju perkeringatan pada ternak. Penelitian dilakukan di RPH Gadang, Kota Malang. Pelaksanaan penelitian dimulai pada bulan Mei - Juli 2018 dengan metode survei lapang. Pengamatan sweating rate (kecepatan perkeringatan) dilakukan pada 20 ekor sapi, yaitu 10 ekor (jantan) PO dan 10 ekor Simpo (jantan), sedang pengamatan HTC dilakukan pada 20 ekor sapi, yaitu 10 ekor sapi PO (jantan) dan 10 ekor sapi Simpo (jantan), dengan vi rataan umur masing masing kurang lebih 2 tahun dan bobot badan 300 kg. Variabel yang diamati berupa, suhu tubuh sapi yang diukur melalui suhu rektal dengan menggunakan thermometer klinis, frekuensi pernafasan dihitung menggunakan hand tally counter dan sweating rate dengan mengamati waktu perubahan CCD 10 % (Cobalt Chloride Disc) dari warna biru berubah ke warna semula (merah muda). Analisis data dilakukan dengan menggunakan uji student-t (uji t) tidak berpasangan. Berdasarkan hasil analisa statistik didapatkan bahwa perbedaan bangsa sapi tidak menghasilkan perbedaan yang nyata (P>0,05) terhadap suhu rektal (38,7oC dan 38,9oC) dan frekuensi pernafasan (27,8 dan 28,2 kali/menit), masing masing berurutan pada sapi PO dan Simpo. Perbedaan bangsa ternak tidak menghasilkan perbedaan yang nyata (P>0,05) terhadap nilai HTC ternak. Berdasarkan penelitian ini dihasilkan nilai HTC pada kedua bangsa sapi yaitu (2,22±0,02 dan 2,24±0,05) diketahui bahwa kedua bangsa sapi sama-sama mengalami cekaman panas, dilihat dari nilai HTC yang berada di atas dua. Hasil analisa statistik menunjukkan bahwa ada perbedaan yang nyata (P<0,05) pada sweating rate antara sapi PO dan Simpo-. Berdasarkan hasil penelitian dapat disimpulkan bahawa Sapi PO memliki suhu tubuh dan HTC yang sama dengan Persilangan Simmental (Simpo) yang ditunjukan dengan nilai Rataan HTC masing-masing 2,22 dan 2,24. PO dan Persilangan dengan Simmental (Simpo) memiliki Sweating rate yang berbeda dengan rataan masing - masing 86,83±5,11 dan 79,03±4,57 g/m²h. dari hasil ini dapat diketahui bahwa daya adaptasi dan tingkat keluarnya keringat dari sapi PO lebih baik dibandingkan dengan sapi Peranakan Bos Taurus (Simpo) yang berasal dari daerah yang beriklim sedang

Response of cow's milk composition to changes in environmental temperature : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University

The need for greater production of animal proteins in the developing countries stems from two factors. Protein deficiency among growing populations due to a wide gap between production and consumption and the continuing demand for the conventional proteins despite the availability of synthetic substitutes French 1970. Studies with regard to the nutritional properties of dairy products Henry 1957; McGillivray and Porter 1960. McGillivray and Gregory 1962 showed that the (protein) fraction of milk was well balanced in the essential amino acids enchancing their nutritive value. Milk production at the desired levels has not been possible in humid and arid regions of the world due to a variety of technical problems chief of which have been the choice of dairy breeds and the availability of good quality pasture, Payne 1957. Cattle breeds indigenous to these regions are poor milk producers. They are slow developing, late maturing animals with short lactatious, long dry periods and poor milk let down; factors which probably contribute to their higher heat tolerance, a character incompatible with high milk yields Mahadevan and Marples 1961. In the United States of America Red Sindhi and Brahman breeds were used in cross breeding programmes aimed at evolving a heat tolerant high producing dairy breed for the gulf coast areas. The first generation Jersey Sindhi and Jersey Brahman crosses not only produced less milk than their contemporary pure Jerseys, but also lacked persistency and a suitable dairy temperament; which were in fact heritable. Brandon McDowell and Brown 1966. These observations do not preclude however the advantages of cross breeding for higher milk production in the tropics Legates 1966; Salazar 1968. Although early ventures using temperate breeds of cattle for milk production in the tropics have shown results of a disappointing nature Payne 1957, given near temperate conditions found in tropical uplands these breeds could respond well. Trail 1968; Yung Chen Chia 1966