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Rosales AM, Moler JL, Engellant AC, Held AL, Slivka DR. Impact of Topical Capsaicin Cream on Thermoregulation and Perception While Walking in the Cold. Wilderness Environ Med 2024; 35:36-43. [PMID: 38379484 DOI: 10.1177/10806032231223757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
INTRODUCTION Capsaicin, a chili pepper extract, can stimulate increased skin blood flow (SkBF) with a perceived warming sensation on application areas. Larger surface area application may exert a more systemic thermoregulatory response. Capsaicin could assist with maintaining heat transport to the distal extremities, minimizing cold weather injury risk. However, the thermoregulatory and perceptual impact of topical capsaicin cream application prior to exercise in the cold is unknown. METHODS Following application of either a 0.1% capsaicin or control cream to the upper and lower extremities (10 g total, ∼40-50% body surface area), 11 participants in shorts and a t-shirt were exposed to 30 min of cold (0 °C, 40% relative humidity). Exposures comprised of 5 min seated rest, 20 min walking (1.6 m·s-1, 5% grade), and 5 min seated rest. Temperature (skin, core), SkBF, skin conductivity, heart rate, thermal sensation, and thermal comfort were measured throughout. RESULTS The capsaicin treatment did not differ from the control treatment in skin temperature (treatment mean: 30.0 ± 2.5, 30.1 ± 2.4 °C, respectively, p = 0.655), core temperature (treatment mean: 37.3 ± 0.5, 37.4 ± 0.4 °C, respectively, p = 0.113), SkBF (treatment mean: -8.4 ± 10.0, -11.1 ± 10.7 A.U., respectively, p = 0.492), skin conductivity (treatment mean: -0.7 ± 5.1, 0.4 ± 6.4 µS, respectively, p = 0.651), or heart rate (treatment mean: 83 ± 29, 85 ± 28 beats·minute-1, respectively, p = 0.234). The capsaicin and control treatments also did not differ in thermal sensation (p = 0.521) and thermal comfort (p = 0.982), with perceptual outcomes corresponding with feeling "cool" and "just uncomfortable," respectively. CONCLUSIONS 0.1% topical capsaicin application to exposed limbs prior to walking in a cold environment does not alter whole-body thermoregulation or thermal perception.
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Affiliation(s)
- Alejandro M Rosales
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| | - Jessica L Moler
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| | - Andrew C Engellant
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| | - Alice L Held
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| | - Dustin R Slivka
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
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Rosales AM, Walters MJ, McGlynn ML, Collins CW, Slivka DR. Influence of topical menthol gel on thermoregulation and perception while walking in the heat. Eur J Appl Physiol 2024; 124:317-327. [PMID: 37505231 DOI: 10.1007/s00421-023-05279-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/18/2023] [Indexed: 07/29/2023]
Abstract
PURPOSE Menthol is known to elicit opposing thermoregulatory and perceptual alterations during intense exercise. The current purpose was to determine the thermoregulatory and perceptual effects of topical menthol application prior to walking in the heat. METHODS Twelve participants walked (1.6 m s-1, 5% grade) for 30 min in the heat (38 °C, 60% relative humidity) with either a 4% menthol or control gel on the upper (shoulder to wrist) and lower (mid-thigh to ankle) limbs. Skin blood flow (SkBF), sweat (rate, composition), skin conductivity, heart rate, temperature (skin, core), and thermal perception were measured prior to and during exercise. RESULTS Skin conductivity expressed as time to 10, 20, 30, and 40 µS was delayed due to menthol (559 ± 251, 770 ± 292, 1109 ± 301, 1299 ± 335 s, respectively) compared to the control (515 ± 260, 735 ± 256, 935 ± 300, 1148 ± 298 s, respectively, p = 0.048). Sweat rate relative to body surface area was lower due to menthol (0.55 ± 0.16 L h-1 m(2)-1) than the control (0.64 ± 0.16 L h-1 m(2)-1, p = 0.049). Core temperature did not differ at baseline between the menthol (37.4 ± 0.3 °C) and control (37.3 ± 0.4 °C, p = 0.298) but was higher at 10, 20, and 30 min due to menthol (37.5 ± 0.3, 37.7 ± 0.2, 38.1 ± 0.3 °C, respectively) compared to the control (37.3 ± 0.4, 37.4 ± 0.3, 37.7 ± 0.3 °C, respectively, p < 0.05). The largest rise in core temperature from baseline was at 30 min during menthol (0.7 ± 0.3 °C) compared to the control (0.4 ± 0.2 °C, p = 0.004). Overall, the menthol treatment was perceived cooler, reaching "slightly warm" whereas the control treatment reached "warm" (p < 0.001). CONCLUSION Menthol application to the limbs impairs whole-body thermoregulation while walking in the heat despite perceiving the environment as cooler.
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Affiliation(s)
- Alejandro M Rosales
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, 32 Campus Drive, Missoula, MT, 59812, USA
| | - Matthias J Walters
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA
| | - Mark L McGlynn
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA
| | - Christopher W Collins
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA
| | - Dustin R Slivka
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA.
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, 32 Campus Drive, Missoula, MT, 59812, USA.
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Hillen B, Andrés López D, Marzano-Felisatti JM, Sanchez-Jimenez JL, Cibrián Ortiz de Anda RM, Nägele M, Salvador-Palmer MR, Pérez-Soriano P, Schömer E, Simon P, Priego-Quesada JI. Acute physiological responses to a pyramidal exercise protocol and the associations with skin temperature variation in different body areas. J Therm Biol 2023; 115:103605. [PMID: 37329763 DOI: 10.1016/j.jtherbio.2023.103605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/08/2023] [Accepted: 05/27/2023] [Indexed: 06/19/2023]
Abstract
This study aimed to examine the skin temperature (Tsk) variations in five regions of interest (ROI) to assess whether possible disparities between the ROI's Tsk could be associated with specific acute physiological responses during cycling. Seventeen participants performed a pyramidal load protocol on a cycling ergometer. We synchronously measured Tsk in five ROI with three infrared cameras. We assessed internal load, sweat rate, and core temperature. Reported perceived exertion and calves' Tsk showed the highest correlation (r = -0.588; p < 0.01). Mixed regression models revealed that the heart rate and reported perceived exertion were inversely related to calves' Tsk. The exercise duration was directly associated with the nose tip and calf Tsk but inversely related to the forehead and forearm Tsk. The sweat rate was directly related to forehead and forearm Tsk. The association of Tsk with thermoregulatory or exercise load parameters depends on the ROI. The parallel observation of the face and calf Tsk could indicate simultaneously the observation of acute thermoregulatory needs and individual internal load. The separate Tsk analyses of individual ROI appear more suitable to examine specific physiological response than a mean Tsk of several ROI during cycling.
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Affiliation(s)
- Barlo Hillen
- Department of Sports Medicine, Disease Prevention and Rehabilitation, Institute of Sports Science, Johannes Gutenberg University of Mainz, Germany.
| | - Daniel Andrés López
- Research Group of Computational Geometry, Institute of Computer Science, Johannes Gutenberg University of Mainz, Germany
| | - Joaquín Martín Marzano-Felisatti
- Department of Physical Education and Sports, Faculty of Physical Activity and Sports Sciences, GIBD (Research Group in Sports Biomechanics), University of Valencia, Spain
| | - José Luis Sanchez-Jimenez
- Department of Physical Education and Sports, Faculty of Physical Activity and Sports Sciences, GIBD (Research Group in Sports Biomechanics), University of Valencia, Spain
| | - Rosa Maria Cibrián Ortiz de Anda
- Department of Physiology. Faculty of Medicine and Odontology, GIFIME (Biophysics and Medical Physics Group), University of Valencia, Spain
| | | | - Maria Rosario Salvador-Palmer
- Department of Physiology. Faculty of Medicine and Odontology, GIFIME (Biophysics and Medical Physics Group), University of Valencia, Spain
| | - Pedro Pérez-Soriano
- Department of Physical Education and Sports, Faculty of Physical Activity and Sports Sciences, GIBD (Research Group in Sports Biomechanics), University of Valencia, Spain
| | - Elmar Schömer
- Research Group of Computational Geometry, Institute of Computer Science, Johannes Gutenberg University of Mainz, Germany
| | - Perikles Simon
- Department of Sports Medicine, Disease Prevention and Rehabilitation, Institute of Sports Science, Johannes Gutenberg University of Mainz, Germany
| | - Jose Ignacio Priego-Quesada
- Department of Physical Education and Sports, Faculty of Physical Activity and Sports Sciences, GIBD (Research Group in Sports Biomechanics), University of Valencia, Spain; Department of Physiology. Faculty of Medicine and Odontology, GIFIME (Biophysics and Medical Physics Group), University of Valencia, Spain.
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Martínez-Noguera FJ, Cabizosu A, Marín-Pagán C, Alcaraz PE. Body surface profile in ambient and hot temperatures during a rectangular test in race walker champions of the World Cup in Oman 2022. J Therm Biol 2023; 114:103548. [PMID: 37344022 DOI: 10.1016/j.jtherbio.2023.103548] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 06/23/2023]
Abstract
There is current interest in infrared thermography as a method to assess changes in body surface temperature to determine thermoregulatory mechanisms, especially in endurance sports. The aim of this study was to evaluate the effect of two environmental temperatures (17 and 28°C) on body surface temperature in different anterior and posterior aspects of the body during a rectangular test in international walkers of the Spanish National Team. Three international walkers performed a rectangular test, where body temperature was measured at rest, and after the 5th, 10th and 15th run using an infrared thermographic camera in room temperatures at 17 and 28°C. In addition, oxygen consumption was measured simultaneously. ANOVA detected a group × time interaction in the chest and abdomen (right and left), left back and right calf (p = < 0.05), with a trend in the right hamstring (p = 0.053) when comparing 17°C and 28°C. ANOVA detected no significant group × time interaction (p = 0.853) but there was a significant group effect (p = 0.022). The eleven degrees increase in ambient temperature (17 to 28°C) produces changes in almost all anatomical zones, but not homogeneously in international walkers during a rectangular test. This indicates that metabolic and blood flow changes are different depending on the anatomical zone measured.
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Affiliation(s)
- Francisco Javier Martínez-Noguera
- Research Center for High Performance Sport, Catholic University of Murcia, Campus de los Jerónimos, N° 135 UCAM, 30107, Murcia, Spain.
| | - Alessio Cabizosu
- THERMHESC Group, Ribera Hospital de Molina San Antonio Catholic University of Murcia (UCAM), Spain.
| | - Cristian Marín-Pagán
- Research Center for High Performance Sport, Catholic University of Murcia, Campus de los Jerónimos, N° 135 UCAM, 30107, Murcia, Spain.
| | - Pedro E Alcaraz
- Research Center for High Performance Sport, Catholic University of Murcia, Campus de los Jerónimos, N° 135 UCAM, 30107, Murcia, Spain.
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Rosales AM, Powers M, Walters MJ, McGlynn ML, Collins CW, Slivka DR. Influence of topical capsaicin cream on thermoregulation and perception during acute exercise in the heat. J Therm Biol 2023; 113:103535. [PMID: 37055138 DOI: 10.1016/j.jtherbio.2023.103535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/01/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023]
Abstract
PURPOSE Determine if topical capsaicin, a transient receptor potential vanilloid heat thermoreceptor activator, alters thermoregulation and perception when applied topically prior to thermal exercise. METHODS Twelve subjects completed 2 treatments. Subjects walked (1.6 m s-1, 5% grade) for 30 min in the heat (38 °C, 60% relative humidity) with either a capsaicin (0.025% capsaicin) or control cream applied to the upper (shoulder to wrist) and lower (mid-thigh to ankle) limbs covering ∼50% body surface area. Skin blood flow (SkBF), sweat (rate, composition), heart rate, temperature (skin, core), and perceived thermal sensation were measured prior to and during exercise. RESULTS The relative change in SkBF was not different between treatments at any time point (p = 0.284). There were no differences in sweat rate between the capsaicin (1.23 ± 0.37 L h-1) and control (1.43 ± 0.43 L h-1, p = 0.122). There were no differences in heart rate between the capsaicin (122 ± 38 beats·min-1) and control (125 ± 39 beats·min-1, p = 0.431). There were also no differences in weighted surface (p = 0.976) or body temperatures (p = 0.855) between the capsaicin (36.0 ± 1.7 °C, 37.0 ± 0.8 °C, respectively) and control (36.0 ± 1.6 °C, 36.9 ± 0.8 °C, respectively). The capsaicin treatment was not perceived as hotter than the control treatment until minute 30 of exercise (2.8 ± 0.4, 2.5 ± 0.5, respectively, p = 0.038) CONCLUSIONS: Topical capsaicin application does not alter whole-body thermoregulation during acute exercise in the heat despite perceiving the treatment as hotter late in exercise.
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Affiliation(s)
- Alejandro M Rosales
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA; School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, 32 Campus Drive, Missoula, MT, 59812, USA
| | - Marie Powers
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA
| | - Matthias J Walters
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA
| | - Mark L McGlynn
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA
| | - Christopher W Collins
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA
| | - Dustin R Slivka
- School of Health and Kinesiology, University of Nebraska at Omaha, 6001 Dodge Street, Omaha, NE, 68182, USA; School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, 32 Campus Drive, Missoula, MT, 59812, USA.
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6
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Swaney MH, Nelsen A, Sandstrom S, Kalan LR. Sweat and Sebum Preferences of the Human Skin Microbiota. Microbiol Spectr 2023; 11:e0418022. [PMID: 36602383 PMCID: PMC9927561 DOI: 10.1128/spectrum.04180-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/06/2022] [Indexed: 01/06/2023] Open
Abstract
The microorganisms inhabiting human skin must overcome numerous challenges that typically impede microbial growth, including low pH, osmotic pressure, and low nutrient availability. Yet the skin microbiota thrive on the skin and have adapted to these stressful conditions. The limited nutrients available for microbial use in this unique niche include those from host-derived sweat, sebum, and corneocytes. Here, we have developed physiologically relevant, synthetic skin-like growth media composed of compounds present in sweat and sebum. We find that skin-associated bacterial species exhibit unique growth profiles at different concentrations of artificial sweat and sebum. Most strains evaluated demonstrate a preference for high sweat concentrations, while the sebum preference is highly variable, suggesting that the capacity for sebum utilization may be a driver of the skin microbial community structure. In particular, the prominent skin commensal Staphylococcus epidermidis exhibits the strongest preference for sweat while growing equally well across sebum concentrations. Conversely, the growth of Corynebacterium kefirresidentii, another dominant skin microbiome member, is dependent on increasing concentrations of both sweat and sebum but only when sebum is available, suggesting a lipid requirement of this species. Furthermore, we observe that strains with similar growth profiles in the artificial media cluster by phylum, suggesting that phylogeny is a key factor in sweat and sebum use. Importantly, these findings provide an experimental rationale for why different skin microenvironments harbor distinct microbiome communities. In all, our study further emphasizes the importance of studying microorganisms in an ecologically relevant context, which is critical for our understanding of their physiology, ecology, and function on the skin. IMPORTANCE The human skin microbiome is adapted to survive and thrive in the harsh environment of the skin, which is low in nutrient availability. To study skin microorganisms in a system that mimics the natural skin environment, we developed and tested a physiologically relevant, synthetic skin-like growth medium that is composed of compounds found in the human skin secretions sweat and sebum. We find that most skin-associated bacterial species tested prefer high concentrations of artificial sweat but that artificial sebum concentration preference varies from species to species, suggesting that sebum utilization may be an important contributor to skin microbiome composition. This study demonstrates the utility of a skin-like growth medium, which can be applied to diverse microbiological systems, and underscores the importance of studying microorganisms in an ecologically relevant context.
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Affiliation(s)
- Mary Hannah Swaney
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin, Madison, Wisconsin, USA
| | - Amanda Nelsen
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
| | - Shelby Sandstrom
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
| | - Lindsay R. Kalan
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medicine, Division of Infectious Disease, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
- M. G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
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Cramer MN, Gagnon D, Laitano O, Crandall CG. Human temperature regulation under heat stress in health, disease, and injury. Physiol Rev 2022; 102:1907-1989. [PMID: 35679471 PMCID: PMC9394784 DOI: 10.1152/physrev.00047.2021] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/10/2022] [Accepted: 05/28/2022] [Indexed: 12/30/2022] Open
Abstract
The human body constantly exchanges heat with the environment. Temperature regulation is a homeostatic feedback control system that ensures deep body temperature is maintained within narrow limits despite wide variations in environmental conditions and activity-related elevations in metabolic heat production. Extensive research has been performed to study the physiological regulation of deep body temperature. This review focuses on healthy and disordered human temperature regulation during heat stress. Central to this discussion is the notion that various morphological features, intrinsic factors, diseases, and injuries independently and interactively influence deep body temperature during exercise and/or exposure to hot ambient temperatures. The first sections review fundamental aspects of the human heat stress response, including the biophysical principles governing heat balance and the autonomic control of heat loss thermoeffectors. Next, we discuss the effects of different intrinsic factors (morphology, heat adaptation, biological sex, and age), diseases (neurological, cardiovascular, metabolic, and genetic), and injuries (spinal cord injury, deep burns, and heat stroke), with emphasis on the mechanisms by which these factors enhance or disturb the regulation of deep body temperature during heat stress. We conclude with key unanswered questions in this field of research.
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Affiliation(s)
- Matthew N Cramer
- Defence Research and Development Canada-Toronto Research Centre, Toronto, Ontario, Canada
| | - Daniel Gagnon
- Montreal Heart Institute and School of Kinesiology and Exercise Science, Université de Montréal, Montréal, Quebec, Canada
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
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Amin R, Faghih RT. Physiological characterization of electrodermal activity enables scalable near real-time autonomic nervous system activation inference. PLoS Comput Biol 2022; 18:e1010275. [PMID: 35900988 PMCID: PMC9333288 DOI: 10.1371/journal.pcbi.1010275] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 06/02/2022] [Indexed: 12/01/2022] Open
Abstract
Electrodermal activities (EDA) are any electrical phxenomena observed on the skin. Skin conductance (SC), a measure of EDA, shows fluctuations due to autonomic nervous system (ANS) activation induced sweat secretion. Since it can capture psychophysiological information, there is a significant rise in the research work for tracking mental and physiological health with EDA. However, the current state-of-the-art lacks a physiologically motivated approach for real-time inference of ANS activation from EDA. Therefore, firstly, we propose a comprehensive model for the SC dynamics. The proposed model is a 3D state-space representation of the direct secretion of sweat via pore opening and diffusion followed by corresponding evaporation and reabsorption. As the input to the model, we consider a sparse signal representing the ANS activation that causes the sweat glands to produce sweat. Secondly, we derive a scalable fixed-interval smoother-based sparse recovery approach utilizing the proposed comprehensive model to infer the ANS activation enabling edge computation. We incorporate a generalized-cross-validation to tune the sparsity level. Finally, we propose an Expectation-Maximization based deconvolution approach for learning the model parameters during the ANS activation inference. For evaluation, we utilize a dataset with 26 participants, and the results show that our comprehensive state-space model can successfully describe the SC variations with high scalability, showing the feasibility of real-time applications. Results validate that our physiology-motivated state-space model can comprehensively explain the EDA and outperforms all previous approaches. Our findings introduce a whole new perspective and have a broader impact on the standard practices of EDA analysis. The current state-of-the-art lacks physiology-motivated models for electrodermal activities (EDA) that have the power to comprehensively describe the variations in skin conductance (SC)–a measure of EDA. In this study, we propose a physiology-motivated state-space model to address previous challenges. On the other hand, there is also an absence of a scalable autonomic nervous system (ANS) activation inference method that simultaneously solve for the physiological system parameters. Furthermore, we develop a scalable ANS activation inference approach based on the proposed model with a goal for real-time edge computation. We utilize a dataset with 26 participants to validate the new model and the scalable method. Results demonstrate that our physiology-motivated state-space model can comprehensively explain the EDA. Our findings introduce a whole new perspective and have a broader impact on standard practices of EDA analysis.
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Affiliation(s)
- Rafiul Amin
- Department of Electrical and Computer Engineering, University of Houston, Houston, Texas, United States of America
| | - Rose T. Faghih
- Department of Electrical and Computer Engineering, University of Houston, Houston, Texas, United States of America
- Department of Biomedical Engineering, New York University, New York City, New York, United States of America
- * E-mail:
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Abstract
In recent years, wearable sensors have enabled the unique mode of real-time and noninvasive monitoring to develop rapidly in medical care, sports, and other fields. Sweat contains a wide range of biomarkers such as metabolites, electrolytes, and various hormones. Combined with wearable technology, sweat can reflect human fatigue, disease, mental stress, dehydration, and so on. This paper comprehensively describes the analysis of sweat components such as glucose, lactic acid, electrolytes, pH, cortisol, vitamins, ethanol, and drugs by wearable sensing technology, and the application of sweat wearable devices in glasses, patches, fabrics, tattoos, and paper. The development trend of sweat wearable devices is prospected. It is believed that if the sweat collection, air permeability, biocompatibility, sensing array construction, continuous monitoring, self-healing technology, power consumption, real-time data transmission, specific recognition, and other problems of the wearable sweat sensor are solved, we can provide the wearer with important information about their health level in the true sense.
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Wang X, Liu Y, Cheng H, Ouyang X. Surface Wettability for Skin-Interfaced Sensors and Devices. ADVANCED FUNCTIONAL MATERIALS 2022; 32:2200260. [PMID: 36176721 PMCID: PMC9514151 DOI: 10.1002/adfm.202200260] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Indexed: 05/05/2023]
Abstract
The practical applications of skin-interfaced sensors and devices in daily life hinge on the rational design of surface wettability to maintain device integrity and achieve improved sensing performance under complex hydrated conditions. Various bio-inspired strategies have been implemented to engineer desired surface wettability for varying hydrated conditions. Although the bodily fluids can negatively affect the device performance, they also provide a rich reservoir of health-relevant information and sustained energy for next-generation stretchable self-powered devices. As a result, the design and manipulation of the surface wettability are critical to effectively control the liquid behavior on the device surface for enhanced performance. The sensors and devices with engineered surface wettability can collect and analyze health biomarkers while being minimally affected by bodily fluids or ambient humid environments. The energy harvesters also benefit from surface wettability design to achieve enhanced performance for powering on-body electronics. In this review, we first summarize the commonly used approaches to tune the surface wettability for target applications toward stretchable self-powered devices. By considering the existing challenges, we also discuss the opportunities as a small fraction of potential future developments, which can lead to a new class of skin-interfaced devices for use in digital health and personalized medicine.
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Affiliation(s)
- Xiufeng Wang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Yangchengyi Liu
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Huanyu Cheng
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Xiaoping Ouyang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105, China
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11
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Tronstad C, Amini M, Bach DR, Martinsen OG. Current trends and opportunities in the methodology of electrodermal activity measurement. Physiol Meas 2022; 43. [PMID: 35090148 DOI: 10.1088/1361-6579/ac5007] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/28/2022] [Indexed: 11/12/2022]
Abstract
Electrodermal activity (EDA) has been measured in the laboratory since the late 1800s. Although the influence of sudomotor nerve activity and the sympathetic nervous system on EDA is well established, the mechanisms underlying EDA signal generation are not completely understood. Owing to simplicity of instrumentation and modern electronics, these measurements have recently seen a transfer from the laboratory to wearable devices, sparking numerous novel applications while bringing along both challenges and new opportunities. In addition to developments in electronics and miniaturization, current trends in material technology and manufacturing have sparked innovations in electrode technologies, and trends in data science such as machine learning and sensor fusion are expanding the ways that measurement data can be processed and utilized. Although challenges remain for the quality of wearable EDA measurement, ongoing research and developments may shorten the quality gap between wearable EDA and standardized recordings in the laboratory. In this topical review, we provide an overview of the basics of EDA measurement, discuss the challenges and opportunities of wearable EDA, and review recent developments in instrumentation, material technology, signal processing, modeling and data science tools that may advance the field of EDA research and applications over the coming years.
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Affiliation(s)
- Christian Tronstad
- Department of Clinical and Biomedical Engineering, Oslo University Hospital, Sognsvannsveien 20, Oslo, 0372, NORWAY
| | - Maryam Amini
- Physics, University of Oslo Faculty of Mathematics and Natural Sciences, Sem Sælands vei 24, Oslo, 0371, NORWAY
| | - Dominik R Bach
- Wellcome Centre for Human Neuroimaging, University College London, 12 Queen Square, London, London, WC1N 3AZ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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Seehafer L, Morrison S, Severin R, Ness BM. A Multi-Systems Approach to Human Movement after ACL Reconstruction: The Cardiopulmonary System. Int J Sports Phys Ther 2021; 17:60-73. [PMID: 35024206 PMCID: PMC8720251 DOI: 10.26603/001c.29451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/01/2021] [Indexed: 11/23/2022] Open
Abstract
The cardiopulmonary system plays a pivotal role in athletic and rehabilitative activities following anterior cruciate ligament reconstruction, along with serving as an important support for the functioning of other physiologic systems including the integumentary, musculoskeletal, and nervous systems. Many competitive sports impose high demands upon the cardiorespiratory system, which requires careful attention and planning from rehabilitation specialists to ensure athletes are adequately prepared to return to sport. Cardiopulmonary function following anterior cruciate ligament reconstruction (ACLR) can be assessed using a variety of methods, depending on stage of healing, training of the clinician, and equipment availability. Reductions in cardiovascular function may influence the selection and dosage of interventions that are not only aimed to address cardiopulmonary impairments, but also deficits experienced in other systems that ultimately work together to achieve goal-directed movement. The purpose of this clinical commentary is to present cardiopulmonary system considerations within a multi-physiologic systems approach to human movement after ACLR, including a clinically relevant review of the cardiopulmonary system, assessment strategies, and modes of cardiopulmonary training to promote effective, efficient movement. LEVEL OF EVIDENCE 5.
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Affiliation(s)
| | - Scot Morrison
- PhysioPraxis PLLC; Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona
| | - Rich Severin
- Doctor of Physical Therapy Program, Baylor University; Department of Physical Therapy, College of Applied Health Sciences, University of Illinois
| | - Brandon M Ness
- Doctor of Physical Therapy Program, Tufts University School of Medicine
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13
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Lucas K, Todd P, Ness BM. A Multi-Systems Approach to Human Movement after ACL Reconstruction: The Integumentary System. Int J Sports Phys Ther 2021; 17:74-80. [PMID: 35024207 PMCID: PMC8720252 DOI: 10.26603/001c.29454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/01/2021] [Indexed: 11/18/2022] Open
Abstract
Postoperative management of anterior cruciate ligament (ACL) reconstruction has traditionally focused on the evaluation and intervention of musculoskeletal components such as range of motion and patients' reports of function. The integumentary system can provide early indications that rehabilitation may be prolonged due to protracted or poor healing of the incision sites. Full evaluation of the reconstruction over time, including direction of the incisions, appearance of surgical sites, level of residual innervation, and health of the individual should be considered when determining time-based goals and plans for returning an athlete to activity. Skin care techniques should be used to minimize strain and promote wound healing at the surgical sites, which in turn allows for implementation of other interventions that target other body systems such as locomotion, strength training, and cardiopulmonary conditioning. The integration of the integumentary system with cardiovascular, neurological, and muscular systems is required for a successful return to activity. A multi-physiologic systems approach may provide a unique viewpoint when aiming to attain a greater appreciation of the integumentary system and its integration with other body systems following ACL reconstruction. The purpose of this clinical commentary is to discuss integumentary considerations within a multi-physiologic systems approach to human movement after ACL reconstruction, including an anatomical review, key elements of assessment, and integrated intervention strategies. LEVEL OF EVIDENCE 5.
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Affiliation(s)
- Kathryn Lucas
- Kosair Charities Center for Pediatric NeuroRecovery, University of Louisville; Kentucky Spinal Cord Injury Research Center; Department of Neurological Surgery, University of Louisville
| | - Patricia Todd
- Department of Pediatrics, University of Louisville School of Medicine, Norton Children's Pediatric Dermatology
| | - Brandon M Ness
- Doctor of Physical Therapy Program, Tufts University School of Medicine
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14
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Wongsanao T, Leemingsawat W, Panapisal V, Kritpet T. Thermoregulatory effects of guava leaf extract-menthol toner application for post-exercise use. PHARMACEUTICAL BIOLOGY 2021; 59:854-859. [PMID: 34196588 PMCID: PMC8253185 DOI: 10.1080/13880209.2021.1942925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/07/2021] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
CONTEXT Psidium guajava L. (Myrtaceae) leaf contains a wide variety of bioactive compounds that contribute valuable effects on human well-being. OBJECTIVE This study investigates the influence of guava leaf extract-menthol toner on thermoregulation, including perspiration, skin temperature, and recovery heart rate. MATERIALS AND METHODS This randomised, placebo-controlled clinical trial assessed the effects of the guava leaf extract-menthol toner and placebo with a 1-week washout period. Sixty-four participants were enrolled. The participants exercised on a treadmill until a 75% heart rate reserve was achieved for 5 min, followed by a 5 min post-exercise rest period. The skin temperature and heart rate were then measured before 5 mL of the testing product was sprayed to specific areas of the body, left it for 30 sec before wiped off. Post-exercise perspiration and skin temperatures were collected by sweat patches and measured by the Skin-thermometer ST500, respectively. A 20 min heart rate monitoring period started 10 min after the exercise and measured every 2 min intervals. RESULTS Use of the toner significantly reduced post-exercise perspiration to approximately half of the baseline and placebo use values (p < 0.05). Furthermore, relative heart rate changes showed no significant differences among the tests (p > 0.05). Skin temperature was also unaffected (p > 0.05). DISCUSSION AND CONCLUSION Guava leaf extract-menthol toner reduced perspiration by astringent effects but did not influence heat dissipation and did not affect cardiovascular mechanism compared to the controls. Additional cleaning with guava leaf extract-menthol toner could offer better hygiene after a workout.
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Affiliation(s)
- Titeyut Wongsanao
- Faculty of Sports Science, Chulalongkorn University, Bangkok, Thailand
| | | | - Vipaporn Panapisal
- Department of Pharmaceutics and Industrial Pharmacy and Cosmetics Strategic Research Unit, Chulalongkorn University Drug and Health Products Innovation & Promotion Center, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
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15
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Gerrett N, Amano T, Inoue Y, Kondo N. Eccrine sweat glands' maximum ion reabsorption rates during passive heating in older adults (50-84 years). Eur J Appl Physiol 2021; 121:3145-3159. [PMID: 34370049 DOI: 10.1007/s00421-021-04766-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/05/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE We examined whether eccrine sweat glands ion reabsorption rate declined with age in 35 adults aged 50-84 years. Aerobic fitness (VO2max) and salivary aldosterone were measured to see if they modulated ion reabsorption rates. METHODS During a passive heating protocol (lower leg 42 °C water submersion) the maximum ion reabsorption rates from the chest, forearm and thigh were measured, alongside other thermophysiological responses. The maximum ion reabsorption rate was defined as the inflection point in the slope of the relation between galvanic skin conductance and sweat rate. RESULTS The maximum ion reabsorption rate at the forearm, chest and thigh (0.29 ± 0.16, 0.33 ± 0.15, 0.18 ± 0.16 mg/cm2/min, respectively) were weakly correlated with age (r ≤ - 0.232, P ≥ 0.05) and salivary aldosterone concentrations (r ≤ - 0.180, P ≥ 0.179). A moderate positive correlation was observed between maximum ion reabsorption rate at the thigh and VO2max (r = 0.384, P = 0.015). Salivary aldosterone concentration moderately declined with age (r = - 0.342, P = 0.021). Whole body sweat rate and pilocarpine-induced sudomotor responses to iontophoresis increased with VO2max (r ≥ 0.323, P ≤ 0.027) but only moderate (r = - 0.326, P = 0.032) or no relations (r ≤ - 0.113, P ≥ 0.256) were observed with age. CONCLUSION The eccrine sweat glands' maximum ion reabsorption rate is not affected by age, spanning 50-84 years. Aldosterone concentration in an aged cohort does not appear to modulate the ion reabsorption rate. We provide further support for maintaining cardiorespiratory fitness to attenuate any decline in sudomotor function.
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Affiliation(s)
- N Gerrett
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-Ku, Kobe, 657-8501, Japan.,Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - T Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Y Inoue
- Laboratory for Human Performance Research, Osaka International University, Osaka, Japan
| | - 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.
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Yin S, Liu X, Kaji T, Nishina Y, Miyake T. Fiber-crafted biofuel cell bracelet for wearable electronics. Biosens Bioelectron 2021; 179:113107. [PMID: 33640657 DOI: 10.1016/j.bios.2021.113107] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/19/2022]
Abstract
Wearable devices that generate power using sweat have garnered much attention in the field of skin electronics. These devices require high performance with a small volume and low production rate of sweat by living organisms. Here we demonstrate a high-power biofuel cell bracelet based on the lactate in human sweat. The biofuel cell was developed by using a lactate oxidase/osmium-based mediator/carbon nanotube fiber for lactate oxidation and a bilirubin oxidase/carbon nanotube fiber for oxygen reduction; the fibers were woven into a hydrophilic supportive textile for sweat storage. The storage textile was sandwiched between a hydrophobic textile for sweat absorption from the skin and a hydrophilic textile for water evaporation to improve sweat collection. The performance of the layered cell was 74 μW at 0.39 V in 20 mM artificial sweat lactate, and its performance was maintained at over 80% for 12 h. Furthermore, we demonstrated a series-connection between anode/cathode fibers by tying them up to wrap the bracelet-type biofuel cell on the wrist. The booster six-cell bracelet generated power at 2.0 V that is sufficient for operating digital wrist watches.
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Affiliation(s)
- Sijie Yin
- Graduate School of Information, Production and Systems, Waseda University, 2-7 Hibikino, Wakamatsu, Kitakyushu, Fukuoka, 808-0135, Japan
| | - Xiaohan Liu
- Graduate School of Information, Production and Systems, Waseda University, 2-7 Hibikino, Wakamatsu, Kitakyushu, Fukuoka, 808-0135, Japan
| | - Tatsuya Kaji
- Graduate School of Natural Science and Technology, Okayama University, Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan
| | - Yuta Nishina
- Graduate School of Natural Science and Technology, Okayama University, Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan
| | - Takeo Miyake
- Graduate School of Information, Production and Systems, Waseda University, 2-7 Hibikino, Wakamatsu, Kitakyushu, Fukuoka, 808-0135, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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Ohashi T, Gerrett N, Shinkawa S, Sato T, Miyake R, Kondo N, Mitsuzawa S. Fluidic Patch Device to Sample Sweat for Accurate Measurement of Sweat Rate and Chemical Composition: A Proof-of-Concept Study. Anal Chem 2020; 92:15534-15541. [PMID: 33169984 DOI: 10.1021/acs.analchem.0c03466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Sweat sensors that can continuously sample sweat are critical for determining the time-dependent physiological responses occurring in normal daily life. Here, a new device, termed fluidic patch, for collecting human sweat samples at defined time intervals is developed, and the proof-of-concept is demonstrated. The device comprises micropumps and a disposable microfluidic patch attached to the human skin. The fluidic patch continuously collects aliquots of freshly secreted sweat accumulated in the fluidic pathway at accurately defined time windows (typically 5 min). By measuring the weight of the collected samples, the local sweat rate is calculated. The sweat sample collected can be directly subjected to a wide range of chemical analyses. For the proof-of-concept, we compared the sweat rates during passive heating in human trials using the fluidic patch and the conventional ventilated sweat capsule system. Although the sweat rate obtained using the fluidic patch highly correlated with that of the ventilated sweat capsule (R2 = 0.96, y = 1.4x - 0.05), the fluidic patch overestimated the sweat rate compared with the ventilated capsule system when the sweat rate exceeded 0.5 mg/(cm2·min). The sampled sweat was analyzed for sodium, potassium, chloride, lactate, pyruvate, and cortisol. The device could obtain the time courses of the concentrations of the abovementioned three ions; the concentrations of sodium and chloride increased linearly with the sweat rate during passive heating (R2 = 0.76 and 0.66, respectively). The device can reliably measure the sweat rate and collect sweat samples for chemical analysis. It can be utilized for real-time physiological investigations toward wider applications.
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Affiliation(s)
- Tomoaki Ohashi
- Honda Research Institute Japan Co., Ltd., 8-1 Honcho, Wako 351-0188, Japan
| | - Nicola Gerrett
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan.,Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7-9, 1081 BT Amsterdam, The Netherlands
| | - Satoru Shinkawa
- Honda Research Institute Japan Co., Ltd., 8-1 Honcho, Wako 351-0188, Japan
| | - Tomomi Sato
- Microfluidic Integrated Circuits Research Laboratory, Graduate School of Engineering, The University of Tokyo, 7-7 Shinkawasaki, Saiwai-ku, Kawasaki 212-0032, Japan
| | - Ryo Miyake
- Microfluidic Integrated Circuits Research Laboratory, Graduate School of Engineering, The University of Tokyo, 7-7 Shinkawasaki, Saiwai-ku, Kawasaki 212-0032, Japan
| | - 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
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Amin MR, Faghih RT. Identification of Sympathetic Nervous System Activation From Skin Conductance: A Sparse Decomposition Approach With Physiological Priors. IEEE Trans Biomed Eng 2020; 68:1726-1736. [PMID: 33119508 DOI: 10.1109/tbme.2020.3034632] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Sweat secretions lead to variations in skin conductance (SC) signal. The relatively fast variation of SC, called the phasic component, reflects sympathetic nervous system activity. The slow variation related to thermoregulation and general arousal is known as the tonic component. It is challenging to decompose the SC signal into its constituents to decipher the encoded neural information related to emotional arousal. METHODS We model the phasic component using a second-order differential equation representing the diffusion and evaporation processes of sweating. We include a sparse impulsive neural signal that stimulates the sweat glands for sweat production. We model the tonic component with several cubic B-spline functions. We formulate an optimization problem with physiological priors on system parameters, a sparsity prior on the neural stimuli, and a smoothness prior on the tonic component. Finally, we employ a generalized-cross-validation-based coordinate descent approach to balance among the smoothness of the tonic component, the sparsity of the neural stimuli, and the residual. RESULTS We illustrate that we can successfully recover the unknowns separating both tonic and phasic components from both experimental and simulated data (with ). Further, we successfully demonstrate our ability to automatically identify the sparsity level for the neural stimuli and the smoothness level for the tonic component. CONCLUSION Our generalized-cross-validation-based novel method for SC signal decomposition successfully addresses previous challenges and retrieves a physiologically plausible solution. SIGNIFICANCE Accurate decomposition of SC could potentially improve cognitive stress tracking in patients with mental disorders.
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Gerrett N, Amano T, Inoue Y, Kondo N. The sweat glands' maximum ion reabsorption rates following heat acclimation in healthy older adults. Exp Physiol 2020; 106:302-315. [PMID: 33006218 DOI: 10.1113/ep088486] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 09/11/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question to this study? Do the sweat glands' maximum ion reabsorption rates increase following heat acclimation in healthy older individuals and is this associated with elevated aldosterone concentrations? What is the main finding and its importance? Sweat gland maximum ion reabsorption rates improved heterogeneously across body sites, which occurred without any changes in aldosterone concentration following a controlled hyperthermic heat acclimation protocol in healthy older individuals. ABSTRACT We examined whether the eccrine sweat glands' ion reabsorption rates improved following heat acclimation (HA) in older individuals. Ten healthy older adults (>65 years) completed a controlled hyperthermic (+0.9°C rectal temperature, Tre ) HA protocol for nine non-consecutive days. Participants completed a passive heat stress test (lower leg 42°C water submersion) pre-HA and post-HA to assess physiological regulation of sweat gland ion reabsorption at the chest, forearm and thigh. The maximum ion reabsorption rate was defined as the inflection point in the slope of the relation between galvanic skin conductance and sweat rate (SR). We explored the responses again after a 7-day decay. During passive heating, the Tb thresholds for sweat onset on the chest and forearm were lowered after HA (P < 0.05). However, sweat sensitivity (i.e. the slope), the SR at a given Tre and gross sweat loss did not improve after HA (P > 0.05). Any changes observed were lost during the decay. Pilocarpine-induced sudomotor responses to iontophoresis did not change after HA (P ≥ 0.801). Maximum ion reabsorption rate was only enhanced at the chest (P = 0.001) despite unaltered aldosterone concentration after HA. The data suggest that this adaptation is lost after 7 days' decay. The HA protocol employed in the present study induced partial adaptive sudomotor responses. Eccrine sweat gland ion reabsorption rates improved heterogeneously across the skin sites. It is likely that aldosterone secretion did not alter the chest sweat ion reabsorption rates observed in the older adults.
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Affiliation(s)
- Nicola Gerrett
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan.,Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Tatsuro Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Yoshimitsu Inoue
- Laboratory for Human Performance Research, Osaka International University, Osaka, Japan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan
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Klous L, De Ruiter C, Alkemade P, Daanen H, Gerrett N. Sweat rate and sweat composition during heat acclimation. J Therm Biol 2020; 93:102697. [DOI: 10.1016/j.jtherbio.2020.102697] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/14/2022]
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Baker LB. Physiology of sweat gland function: The roles of sweating and sweat composition in human health. Temperature (Austin) 2019; 6:211-259. [PMID: 31608304 PMCID: PMC6773238 DOI: 10.1080/23328940.2019.1632145] [Citation(s) in RCA: 242] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/06/2019] [Accepted: 06/08/2019] [Indexed: 12/21/2022] Open
Abstract
The purpose of this comprehensive review is to: 1) review the physiology of sweat gland function and mechanisms determining the amount and composition of sweat excreted onto the skin surface; 2) provide an overview of the well-established thermoregulatory functions and adaptive responses of the sweat gland; and 3) discuss the state of evidence for potential non-thermoregulatory roles of sweat in the maintenance and/or perturbation of human health. The role of sweating to eliminate waste products and toxicants seems to be minor compared with other avenues of excretion via the kidneys and gastrointestinal tract; as eccrine glands do not adapt to increase excretion rates either via concentrating sweat or increasing overall sweating rate. Studies suggesting a larger role of sweat glands in clearing waste products or toxicants from the body may be an artifact of methodological issues rather than evidence for selective transport. Furthermore, unlike the renal system, it seems that sweat glands do not conserve water loss or concentrate sweat fluid through vasopressin-mediated water reabsorption. Individuals with high NaCl concentrations in sweat (e.g. cystic fibrosis) have an increased risk of NaCl imbalances during prolonged periods of heavy sweating; however, sweat-induced deficiencies appear to be of minimal risk for trace minerals and vitamins. Additional research is needed to elucidate the potential role of eccrine sweating in skin hydration and microbial defense. Finally, the utility of sweat composition as a biomarker for human physiology is currently limited; as more research is needed to determine potential relations between sweat and blood solute concentrations.
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Affiliation(s)
- Lindsay B Baker
- Gatorade Sports Science Institute, PepsiCo R&D Physiology and Life Sciences, Barrington, IL, USA
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22
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The influence of local skin temperature on the sweat glands maximum ion reabsorption rate. Eur J Appl Physiol 2019; 119:685-695. [DOI: 10.1007/s00421-018-04059-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/18/2018] [Indexed: 10/27/2022]
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