151
|
Shafirstein G, Moros EG. Modelling millimetre wave propagation and absorption in a high resolution skin model: the effect of sweat glands. Phys Med Biol 2011; 56:1329-39. [DOI: 10.1088/0031-9155/56/5/007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
152
|
Sudbury JR, Ciura S, Sharif-Naeini R, Bourque CW. Osmotic and thermal control of magnocellular neurosecretory neurons - role of an N-terminal variant of trpv1. Eur J Neurosci 2010; 32:2022-30. [DOI: 10.1111/j.1460-9568.2010.07512.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
153
|
Charkoudian N. Optimizing heat dissipation for every environment: the cool ability of the skin to locally regulate sweating. J Appl Physiol (1985) 2010; 109:1288-9. [DOI: 10.1152/japplphysiol.01013.2010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- N. Charkoudian
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| |
Collapse
|
154
|
Sweat Rate and Electrolyte Concentration in Swimmers, Runners, and Nonathletes. Int J Sports Physiol Perform 2010; 5:359-66. [DOI: 10.1123/ijspp.5.3.359] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Because swimmers train in an aquatic environment, they probably do not need to sweat as much as runners who train on land and, therefore, should not develop the same magnitude of sweating adaptations.Purpose:To compare sweat rate and electrolyte concentration in swimmers, runners and nonathletes.Methods:Ten swimmers (22.9 ± 3.1 years old), 10 runners (25 ± 2.9 y) and 10 nonathletes (26.5 ± 2.2 y) cycled in the heat (32°C and 40% relative humidity) for 30 min at similar intensity relative to their maximal cycle test. Sweat volume was calculated from the difference of their body mass before and after cycling, since they were not allowed to drink. Sweat was collected from the scapula using absorbent patch placed on the skin that was cleaned with distilled water. After cycling, the patch was transferred to syringe and the sample was obtained when squeezing it to a tube. Concentration of sodium ([Na+]), chloride ([Cl–]) and potassium ([K+]) were analyzed using an ion selector analyzer.Results:The sweat volume, in liters, of swimmers (0.9 ± 0.3) was lower (P < .05) than that of runners (1.5 ± 0.2) and similar to that of nonathletes (0.6 ± 0.2). [Na+] and [Cl-], in mmolL-1, of swimmers (65.4 ± 5.5 and 61.2 ± 81), and nonathletes (67.3 ± 8.5 and 58.3 ± 9.6) were higher (P < .05) than those of runners (45.2 ± 7.5 and 38.9 ± 8.3). [K+] was similar among groups.Conclusions:The lower sweat volume and higher sweat [Na+] and [Cl-] of swimmers, as compared with runners, indicate that training in the water does not cause the same magnitude of sweating adaptations.
Collapse
|
155
|
Crandall CG, Wilson TE, Kregel KC. Mechanisms and modulators of temperature regulation. J Appl Physiol (1985) 2010; 109:1219-20. [PMID: 20724573 DOI: 10.1152/japplphysiol.00921.2010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
156
|
Wingo JE, Low DA, Keller DM, Brothers RM, Shibasaki M, Crandall CG. Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans. J Appl Physiol (1985) 2010; 109:1301-6. [PMID: 20705945 DOI: 10.1152/japplphysiol.00646.2010] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34°C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20°C (2 sites) or maintenance at 34°C (2 sites). In both protocols, individuals were then passively heated to increase core temperature ~1°C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 ± 1.2 vs. 1.0 ± 0.7 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased skin blood flow, P = 0.01; 1.2 ± 0.9 vs. 0.07 ± 0.05 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 ± 0.4 vs. 37.6 ± 0.4°C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature.
Collapse
Affiliation(s)
- Jonathan E Wingo
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX 75231, USA
| | | | | | | | | | | |
Collapse
|
157
|
Vanos JK, Warland JS, Gillespie TJ, Kenny NA. Review of the physiology of human thermal comfort while exercising in urban landscapes and implications for bioclimatic design. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2010; 54:319-34. [PMID: 20155515 DOI: 10.1007/s00484-010-0301-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 12/07/2009] [Accepted: 01/08/2010] [Indexed: 05/13/2023]
Abstract
This review comprehensively examines scientific literature pertaining to human physiology during exercise, including mechanisms of heat formation and dissipation, heat stress on the body, the importance of skin temperature monitoring, the effects of clothing, and microclimatic measurements. This provides a critical foundation for microclimatologists and biometeorologists in the understanding of experiments involving human physiology. The importance of the psychological aspects of how an individual perceives an outdoor environment are also reviewed, emphasizing many factors that can indirectly affect thermal comfort (TC). Past and current efforts to develop accurate human comfort models are described, as well as how these models can be used to develop resilient and comfortable outdoor spaces for physical activity. Lack of suitable spaces plays a large role in the deterioration of human health due to physical inactivity, leading to higher rates of illness, heart disease, obesity and heat-related casualties. This trend will continue if urban designers do not make use of current knowledge of bioclimatic urban design, which must be synthesized with physiology, psychology and microclimatology. Increased research is required for furthering our knowledge on the outdoor human energy balance concept and bioclimatic design for health and well-being in urban areas.
Collapse
Affiliation(s)
- Jennifer K Vanos
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada.
| | | | | | | |
Collapse
|
158
|
Kondo N, Nishiyasu T, Inoue Y, Koga S. Non-thermal modification of heat-loss responses during exercise in humans. Eur J Appl Physiol 2010; 110:447-58. [PMID: 20512585 DOI: 10.1007/s00421-010-1511-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2010] [Indexed: 10/19/2022]
Abstract
This review focuses on the characteristics of heat-loss responses during exercise with respect to non-thermal factors. In addition, the effects of physical training on non-thermal heat-loss responses are discussed. When a subject is already sweating the sweating rate increases at the onset of dynamic exercise without changes in core temperature, while cutaneous vascular conductance (skin blood flow) is temporarily decreased. Although exercise per se does not affect the threshold for the onset of sweating, it is possible that an increase in exercise intensity induces a higher sensitivity of the sweating response. Exercise increases the threshold for cutaneous vasodilation, and at higher exercise intensities, the sensitivity of the skin-blood-flow response decreases. Facilitation of the sweating response with increased exercise intensity may be due to central command, peripheral reflexes in the exercising muscle, and mental stimuli, whereas the attenuation of skin-blood-flow responses with decreased cutaneous vasodilation is related to many non-thermal factors. Most non-thermal factors have negative effects on magnitude of cutaneous vasodilation; however, several of these factors have positive effects on the sweating response. Moreover, thermal and non-thermal factors interact in controlling heat-loss responses, with non-thermal factors having a greater impact until core temperature elevations become significant, after which core temperature primarily would control heat loss. Finally, as with thermally induced sweating responses, physical training seems to also affect sweating responses governed by non-thermal factors.
Collapse
Affiliation(s)
- Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan.
| | | | | | | |
Collapse
|
159
|
Wilson TE, Monahan KD, Fogelman A, Kearney ML, Sauder CL, Ray CA. Aerobic training improves in vivo cholinergic responsiveness but not sensitivity of eccrine sweat glands. J Invest Dermatol 2010; 130:2328-30. [PMID: 20463689 DOI: 10.1038/jid.2010.125] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
160
|
Kounalakis SN, Botonis PG, Koskolou MD, Geladas ND. The effect of menthol application to the skin on sweating rate response during exercise in swimmers and controls. Eur J Appl Physiol 2010; 109:183-9. [DOI: 10.1007/s00421-009-1345-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2009] [Indexed: 10/20/2022]
|
161
|
Thermometry and calorimetry assessment of sweat response during exercise in the heat. Eur J Appl Physiol 2009; 108:905-11. [DOI: 10.1007/s00421-009-1302-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2009] [Indexed: 11/26/2022]
|
162
|
Saari A, Tolonen U, Pääkkö E, Suominen K, Jauhiainen J, Sotaniemi KA, Myllylä VV. Sweating impairment in patients with multiple sclerosis. Acta Neurol Scand 2009; 120:358-63. [PMID: 19456306 DOI: 10.1111/j.1600-0404.2009.01164.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To measure sweating in patients with multiple sclerosis (MS). MATERIALS AND METHODS Sweating was measured by an evaporimeter after a heating stimulus in 29 MS patients and in 15 healthy control subjects. RESULTS The MS patients sweated markedly less than the controls. After 10 min of heating the sweating was significantly lower in the forehead (P = 0.034), feet (right, P = 0.033; left, P = 0.037) and legs (right, P = 0.043; left, P = 0.029) of the MS patients than in those of the controls. After 15 min of heating the difference was statistically significant only in the feet (right, P = 0.043; left, P = 0.029). The Expanded Disability Status Scale score correlated inversely with sweating at 15 min of heating in the left hand (r = 0.42, P < 0.05), and in the left (r = 0.36, P < 0.05) and right foot (r = 0.37, P < 0.05). CONCLUSIONS MS is associated with an impairment in thermoregulatory sweating which seems to be related to the disease severity.
Collapse
Affiliation(s)
- A Saari
- Department of Neurology, Oulu University Hospital, Oulu, Finland.
| | | | | | | | | | | | | |
Collapse
|
163
|
McKinley MJ, Weissenborn F, Mathai ML. Drinking-induced thermoregulatory panting in rehydrated sheep: influences of oropharyngeal/esophageal signals, core temperature, and thirst satiety. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1881-8. [DOI: 10.1152/ajpregu.90890.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dehydrated mammals conserve body water by reducing thermoregulatory evaporative cooling responses e.g., panting and sweating. Increased core temperature (Tc) may result. Following rehydration and correction of fluid deficits, panting and sweating commence. We investigated the role of oropharyngeal/esophageal, postabsorptive and thermal signals in the panting response, and reduced Tc that occurs when unshorn sheep drink water following water deprivation for 2 days (ambient temperature 20°C). Ingestion of water (at body temperature) resulted in increased respiratory rate (panting) and reduced Tc within 4 min that persisted for at least 90 min. Initially, a similar panting response and reduced Tc occurred following rehydration by drinking isotonic saline solution, but panting was not sustained after 20 min, and Tc began to rise again. Rehydration by intraruminal administration of water, without any drinking, resulted in delayed panting and fall in Tc. Intraruminal infusion of saline was ineffective. Rehydration by drinking cool water (20°C) resulted in a rapid fall in Tc without increased panting. Shorn sheep had lower basal Tc that did not increase during 2 days of water deprivation, and they did not pant on rehydration by drinking water. Our results indicate that signals from the oropharyngeal and/or esophageal region associated with the act of drinking play a crucial role in the initial 20–30 min of the panting response to rehydration. Postabsorptive factors most likely reduced plasma tonicity and cause continued panting and further reduction in Tc. Tc also influences rehydration-induced panting. It occurs only if sheep incur a heat load during bodily dehydration.
Collapse
|
164
|
Cheuvront SN, Bearden SE, Kenefick RW, Ely BR, Degroot DW, Sawka MN, Montain SJ. A simple and valid method to determine thermoregulatory sweating threshold and sensitivity. J Appl Physiol (1985) 2009; 107:69-75. [PMID: 19423839 DOI: 10.1152/japplphysiol.00250.2009] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sweating threshold temperature and sweating sensitivity responses are measured to evaluate thermoregulatory control. However, analytic approaches vary, and no standardized methodology has been validated. This study validated a simple and standardized method, segmented linear regression (SReg), for determination of sweating threshold temperature and sensitivity. Archived data were extracted for analysis from studies in which local arm sweat rate (m(sw); ventilated dew-point temperature sensor) and esophageal temperature (T(es)) were measured under a variety of conditions. The relationship m(sw)/T(es) from 16 experiments was analyzed by seven experienced raters (Rater), using a variety of empirical methods, and compared against SReg for the determination of sweating threshold temperature and sweating sensitivity values. Individual interrater differences (n = 324 comparisons) and differences between Rater and SReg (n = 110 comparisons) were evaluated within the context of biologically important limits of magnitude (LOM) via a modified Bland-Altman approach. The average Rater and SReg outputs for threshold temperature and sensitivity were compared (n = 16) using inferential statistics. Rater employed a very diverse set of criteria to determine the sweating threshold temperature and sweating sensitivity for the 16 data sets, but interrater differences were within the LOM for 95% (threshold) and 73% (sensitivity) of observations, respectively. Differences between mean Rater and SReg were within the LOM 90% (threshold) and 83% (sensitivity) of the time, respectively. Rater and SReg were not different by conventional t-test (P > 0.05). SReg provides a simple, valid, and standardized way to determine sweating threshold temperature and sweating sensitivity values for thermoregulatory studies.
Collapse
Affiliation(s)
- Samuel N Cheuvront
- US Army Research Institute of Environmental Medicine, Thermal and Mountain Medicine Division, Kansas St., Natick, MA 01760-5007, USA.
| | | | | | | | | | | | | |
Collapse
|
165
|
Shibasaki M, Davis SL, Cui J, Low DA, Keller DM, Crandall CG. Botulinum toxin abolishes sweating via impaired sweat gland responsiveness to exogenous acetylcholine. Br J Dermatol 2009; 161:757-61. [PMID: 19538183 DOI: 10.1111/j.1365-2133.2009.09248.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Botulinum toxin A (BTX) disrupts neurotransmitter release from cholinergic nerves. The effective duration of impaired sweat secretion with BTX is longer relative to that of impaired muscle contraction, suggesting different mechanisms in these tissues. OBJECTIVES The aim of this study was to test the hypothesis that BTX is capable of altering sweating by reducing the responsiveness of the sweat gland to acetylcholine. METHODS BTX was injected into the dorsal forearm skin of healthy subjects at least 3 days before subsequent assessment. On the day of the experiment, intradermal microdialysis probes were placed within the BTX-treated area and in an adjacent untreated area. Incremental doses of acetylcholine were administered through the microdialysis membranes while the sweat rate (protocol 1; n = 8) or a combination of sweat rate and skin blood flow (protocol 2; n = 8) were assessed. RESULTS A relative absence of sweating was observed at the BTX site for both protocols (protocol 1: 0.05 +/- 0.09 mg cm(-2) min(-1); protocol 2: 0.03 +/- 0.04 mg cm(-2) min(-1), both at the highest dose of acetylcholine), while the sweat rate increased appropriately at the control sites (protocol 1: 0.90 +/- 0.46 mg cm(-2) min(-1); protocol 2: 1.07 +/- 0.67 mg cm(-2) min(-1)). Cutaneous vascular conductance increased to a similar level at both the BTX and control sites. CONCLUSIONS These results demonstrate that BTX is capable of inhibiting sweat secretion by reducing the responsiveness of the sweat gland to acetylcholine, while not altering acetylcholine-mediated cutaneous vasodilatation.
Collapse
Affiliation(s)
- M Shibasaki
- Department of Environmental Health, Nara Women's University, Nara, Japan
| | | | | | | | | | | |
Collapse
|
166
|
Kawada M, Tamada Y, Simizu H, Yanagishita T, Yamashita N, Ishida N, Watanabe D, Yoshida M, Ibi T, Sahashi K, Hashizume Y, Matsumoto Y. Reduction in QSART and vasoactive intestinal polypeptide expression in the skin of Parkinson's disease patients and its relation to dyshidrosis. J Cutan Pathol 2009; 36:517-21. [PMID: 19476518 DOI: 10.1111/j.1600-0560.2008.01086.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND With regards to dyshidrosis in Parkinson's disease (PD), there is no established and consistent view on the occurrence sites, frequency and etiology, although there have been several reports on hypohidrosis of the limbs and sudoresis on the face/cervical region. METHODS Hydrosis in the forearms of PD patients and healthy individuals were compared by quantitative sudomotor axon reflex test (QSART). The expression of various neuropeptides and alpha-synuclein was examined with immunohistochemical staining. RESULTS There was a significant reduction in QSART of PD patients but not of healthy controls. Reduced expression of vasoactive intestinal polypeptide (VIP) was also detected in the sweat glands of PD patients. CONCLUSION Reduction in QSART and VIP expression in the sweat glands might be involved in the dyshidrosis of PD patients.
Collapse
Affiliation(s)
- Morihiro Kawada
- Department of Dermatology, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
167
|
KENNY GLENP, DORMAN LUCYE, WEBB PAUL, DUCHARME MICHELB, GAGNON DANIEL, REARDON FRANCISD, HARDCASTLE STEPHENG, JAY OLLIE. Heat Balance and Cumulative Heat Storage during Intermittent Bouts of Exercise. Med Sci Sports Exerc 2009; 41:588-96. [DOI: 10.1249/mss.0b013e31818c97a9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
168
|
Abstract
BACKGROUND The proliferating abilities of sweat glands are very limited, so researches on the repair and regeneration of sweat glands are important. First of all, we must find out reliable and specific antigen markers of sweat glands. OBJECTIVE To investigate the antigen expression of human eccrine sweat glands. METHODS The development of eccrine sweat glands was investigated by hematoxylin and eosin staining, and the antigen expression was detected by immunohistochemical techniques. RESULTS Human eccrine sweat glands expressed cytokeratin (CK) 7, CK8, CK14, CK18, CK19 and epithelial membrane antigen (EMA). Carcinoembryonic antigen (CEA) was only expressed in sweat glands in the adult skin. Developing and developed sweat glands all had some cells expressing Ki67 and p63 antigens. Epidermal growth factor (EGF) was mainly localized in the secretory cells and ductal cells. Some myoepithelial cells were also labeled with anti-EGF antibody. In the older fetus, positive staining for EGF was seen in the lumen of the secretory portion. EGF receptor (EGFR) was expressed in the ducts. CONCLUSIONS Human eccrine sweat glands express CK7, CK8, CK14, CK18, CK19, CEA, EMA, Ki67, p63, EGF and EGFR. In skin, CEA can be used as a specific immunological marker of sweat glands.
Collapse
Affiliation(s)
- Hai-Hong Li
- Mental Health Center, ShanTou University Medical College, ShanTou, GuangDong Province, China
| | | | | | | |
Collapse
|
169
|
Buono MJ, Claros R, Deboer T, Wong J. Na+ secretion rate increases proportionally more than the Na+ reabsorption rate with increases in sweat rate. J Appl Physiol (1985) 2008; 105:1044-8. [PMID: 18653750 DOI: 10.1152/japplphysiol.90503.2008] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to measure the in vivo Na(+) secretion and Na(+) reabsorption rates of the human eccrine sweat gland with increases in sweat rate. Such data should help to elucidate the physiological mechanism responsible for the previously reported linear relationship between increases in sweat rate and Na(+) concentration in sweat. On 5 days, each subject (n = 10) completed a 30-min exercise bout in an environmental chamber set at 35 degrees C and 40% relative humidity. The intensity for the five exercise bouts in the heat was set to approximate 50, 60, 70, 80, and 90% of age-predicted maximum heart rate. Forearm sweat samples and capillary blood samples were collected during each of the five 30-min exercise bouts. The sweat and blood samples were analyzed for Na(+) concentration in sweat and serum, which were used to calculate the rate of Na(+) secretion and Na(+) reabsorption. The mean correlation between sweat rate and Na(+) concentration in sweat was found to be r = 0.73. Within the sweat rate range of the present study, both Na(+) secretion rate and Na(+) reabsorption rate increased linearly; however, the Na(+) secretion rate increased almost twice as fast (slope = 141 vs. 80). Thus the rate at which Na(+) escaped reabsorption increased with increases in sweat rate and was significantly (P < 0.05) correlated to the Na(+) concentration in sweat (mean r = 0.90). Such results strongly suggest that the physiological mechanism responsible for the previously reported linear increase in Na(+) concentration in sweat seen with increases in sweat rate is that the Na(+) secretion rate increases proportionally more than the Na(+) reabsorption rate.
Collapse
|
170
|
Shamsuddin AKM, Reddy MM, Quinton PM. Iontophoretic β-adrenergic stimulation of human sweat glands: possible assay for cystic fibrosis transmembrane conductance regulator activityin vivo. Exp Physiol 2008; 93:969-81. [DOI: 10.1113/expphysiol.2008.042283] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
171
|
Sharif-Naeini R, Ciura S, Bourque CW. TRPV1 gene required for thermosensory transduction and anticipatory secretion from vasopressin neurons during hyperthermia. Neuron 2008; 58:179-85. [PMID: 18439403 DOI: 10.1016/j.neuron.2008.02.013] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 12/22/2007] [Accepted: 02/13/2008] [Indexed: 11/27/2022]
Abstract
Increases in core body temperature promote thermoregulatory cooling by stimulating sweat production and preemptive renal water reabsorption through the release of vasopressin (VP, antidiuretic hormone). The mechanism by which the hypothalamus orchestrates this anticipatory VP release during hyperthermia is unknown but has been linked to a central thermosensory mechanism. Here, we report that thermal stimuli spanning core body temperatures activate a calcium-permeable, ruthenium red- and SB366791-sensitive nonselective cation conductance in hypothalamic VP neurons. This response is associated with a depolarizing receptor potential and an increase in action potential firing rate, indicating that these neurons are intrinsically thermosensitive. The thermosensitivity of VP neurons isolated from trpv1 knockout (Trpv1(-/-)) mice was significantly lower than that of wild-type counterparts. Moreover, Trpv1(-/-) mice showed an impaired VP response to hyperthermia in vivo. Channels encoded by the trpv1 gene thus confer thermosensitivity in central VP neurons and contribute to the thermal control of VP release in vivo.
Collapse
Affiliation(s)
- Reza Sharif-Naeini
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montreal, QC, Canada
| | | | | |
Collapse
|
172
|
McKinley MJ, McAllen RM, Whyte D, Mathai ML. Central osmoregulatory influences on thermoregulation. Clin Exp Pharmacol Physiol 2007; 35:701-5. [PMID: 18067594 DOI: 10.1111/j.1440-1681.2007.04833.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. Many mammals maintain a constant core body temperature in the face of a heat load by using evaporative cooling responses, such as sweating, panting and spreading of saliva. These cooling mechanisms incur a body fluid deficit if the fluid lost as sweat, saliva or respiratory moisture is not replaced by the ingestion of water; body fluid hypertonicity and hypovolaemia result. 2. Evidence in several mammals shows that, as they become dehydrated, evaporative cooling mechanisms such as sweating and panting are inhibited so that further fluid loss from the body is reduced. As a result, core temperature in the dehydrated animal is maintained at a higher than normal level. 3. Increasing the osmotic pressure of plasma has an inhibitory effect on panting and sweating in mammals. It has been proposed that osmoreceptors mediate these inhibitory influences of plasma hypertonicity on sweating and panting. 4. The suppression of panting in dehydrated sheep is mediated by cerebral osmoreceptors that are probably located in the lamina terminalis. We speculate that osmoreceptors in the lamina terminalis may also influence thermoregulatory sweating. 5. When dehydrated animals drink water, sweating and panting resume rapidly before water has been absorbed from the gut. It is likely that the act of drinking initiates a reflex that can override the osmoreceptor inhibition of panting, resulting in core temperature falling back quickly to a normal level.
Collapse
Affiliation(s)
- M J McKinley
- Howard Florey Institute, University of Melbourne, Melbourne, Victoria Australia.
| | | | | | | |
Collapse
|
173
|
Buono MJ, Ball KD, Kolkhorst FW. Sodium ion concentration vs. sweat rate relationship in humans. J Appl Physiol (1985) 2007; 103:990-4. [PMID: 17600161 DOI: 10.1152/japplphysiol.00015.2007] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to determine the effect of active heat acclimation on the sweat osmolality and sweat sodium ion concentration vs. sweat rate relationship in humans. Eight healthy male volunteers completed 10 days of exercise in the heat. The mean exercising heart rate and core temperature were significantly decreased ( P < 0.05) by 18 beats/min and 0.6°C, respectively, following heat acclimation. Furthermore, sweat osmolality and the sweat sodium ion concentration vs. sweat rate relationships were shifted to the right. Specifically, the slopes of the relationships were not affected by heat acclimation. Rather, heat acclimation significantly reduced the y-intercepts of the sweat osmolality and sweat sodium relationships with sweat rate by 28 mosmol/kgH2O and 15 mmol/l, respectively. Thus there was a significantly lower sweat sodium ion concentration for a given sweat rate following heat acclimation. These results suggest that heat acclimation increases the sodium ion reabsorption capacity of the human eccrine sweat gland.
Collapse
Affiliation(s)
- Michael J Buono
- School of Exercise and Nutritional Sciences, San Diego State University, San Diego, California 92182, USA.
| | | | | |
Collapse
|
174
|
Sievert LL. Variation in sweating patterns: implications for studies of hot flashes through skin conductance. Menopause 2007; 14:742-51. [PMID: 17519802 DOI: 10.1097/gme.0b013e3180577841] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The literature of sweat physiology and population variation in response to heat stress suggests that variation in sweating patterns may affect the measurement of hot flashes. This study examined variation in sweating patterns in Puebla, Mexico, and Amherst, MA, and compared the levels of concordance between subjective and objective measures of hot flashes. DESIGN Thirteen women in Puebla, Mexico, and 15 women in Amherst, MA, aged 45 to 61, completed surveys, body diagrams of heat flow during a hot flash, anthropometric measures, and the measurement of hot flashes through skin conductance monitoring. Hot flashes were measured through sternal (Mexico and Massachusetts) and nuchal (Mexico only) skin conductance. RESULTS Mexican women were significantly more likely to describe the heat of hot flashes on the back of their neck (100% vs 40%) and on their arms and/or hands (85% vs 40%) compared with women in Massachusetts. Hot flashes in the midback were associated with concordance between nuchal, but not sternal, measures of skin conductance and subjective report in Mexico. In comparing average scores for concordance between subjective and sternal measures of hot flashes, there was a higher mean score for true positives in Mexico (61% vs 29%, P=0.06) and a significantly higher mean score for false-negative measures in Massachusetts (57% vs 21%, P=0.04). CONCLUSIONS Variation in rates of concordance between subjective and objective measures were not adequately explained by sweating patterns. Future studies should consider population variation in acclimatization and assess variation in the amount of sweat produced during a hot flash.
Collapse
Affiliation(s)
- Lynnette Leidy Sievert
- Department of Anthropology, University of Massachusetts Amherst, Amherst, MA 01003-9278, USA.
| |
Collapse
|