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Luetkemeier MJ, Allen DR, Huang M, Pizzey FK, Parupia IM, Wilson TE, Davis SL. Skin tattooing impairs sweating during passive whole body heating. J Appl Physiol (1985) 2020; 129:1033-1038. [PMID: 32881627 DOI: 10.1152/japplphysiol.00427.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Tattooing of the skin involves repeated needle insertions to deposit ink into the dermal layer of the skin, potentially damaging eccrine sweat glands and the cutaneous vasculature. This study tested the hypothesis that reflex increases in sweat rate (SR) and cutaneous vasodilation are blunted in tattooed skin (TAT) compared with adjacent healthy skin (CON) during a passive whole body heat stress (WBH). Ten individuals (5 males and 5 females) with a sufficient area of tattooed skin participated in the study. Intestinal temperature (Tint), skin temperature (Tskin), skin blood flow (laser Doppler flux; LDF), and SR were continuously measured during normothermic baseline (34°C water perfusing a tube-lined suit) and WBH (increased Tint 1.0°C via 48°C water perfusing suit). SR throughout WBH was lower for TAT compared with CON (P = 0.033). Accumulated sweating responses during WBH (area under curve) were attenuated in TAT relative to CON (23.1 ± 12.9, 26.9 ± 14.5 mg/cm2, P = 0.043). Sweating threshold, expressed as the onset of sweating in time or Tint from the initiation of WBH, was not different between TAT and CON. Tattooing impeded the ability to obtain LDF measurements. These data suggest that tattooing functionally damages secretion mechanisms, affecting the reflex capacity of the gland to produce sweat, but does not appear to affect neural signaling to initiate sweating. Decreased sweating could impact heat dissipation especially when tattooing covers a higher percentage of body surface area and could be considered a potential long-term clinical side effect of tattooing.NEW & NOTEWORTHY This study is the first to assess the reflex control of sweating in tattooed skin. The novel findings are twofold. First, attenuated increases in sweat rate were observed in tattooed skin compared with adjacent healthy non-tattooed skin in response to a moderate increase (1.0°C) in internal temperature during a passive whole body heat stress. Second, reduced sweating in tattooed skin is likely related to functional damage to the secretory mechanisms of eccrine sweat glands, rendering it less responsive to cholinergic stimulation.
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Affiliation(s)
| | - Dustin R Allen
- Applied Physiology and Wellness, Southern Methodist University, Dallas, Texas.,Health Sciences, Boston University, Boston, Massachusetts
| | - Mu Huang
- Applied Physiology and Wellness, Southern Methodist University, Dallas, Texas.,Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Faith K Pizzey
- Applied Physiology and Wellness, Southern Methodist University, Dallas, Texas
| | - Iqra M Parupia
- Applied Physiology and Wellness, Southern Methodist University, Dallas, Texas
| | - Thad E Wilson
- Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Scott L Davis
- Applied Physiology and Wellness, Southern Methodist University, Dallas, Texas.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas
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Smith CJ. Pediatric Thermoregulation: Considerations in the Face of Global Climate Change. Nutrients 2019; 11:E2010. [PMID: 31454933 PMCID: PMC6770410 DOI: 10.3390/nu11092010] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/10/2019] [Accepted: 08/16/2019] [Indexed: 12/16/2022] Open
Abstract
Predicted global climate change, including rising average temperatures, increasing airborne pollution, and ultraviolet radiation exposure, presents multiple environmental stressors contributing to increased morbidity and mortality. Extreme temperatures and more frequent and severe heat events will increase the risk of heat-related illness and associated complications in vulnerable populations, including infants and children. Historically, children have been viewed to possess inferior thermoregulatory capabilities, owing to lower sweat rates and higher core temperature responses compared to adults. Accumulating evidence counters this notion, with limited child-adult differences in thermoregulation evident during mild and moderate heat exposure, with increased risk of heat illness only at environmental extremes. In the context of predicted global climate change, extreme environmental temperatures will be encountered more frequently, placing children at increased risk. Thermoregulatory and overall physiological strain in high temperatures may be further exacerbated by exposure to/presence of physiological and environmental stressors including pollution, ultraviolet radiation, obesity, diabetes, associated comorbidities, and polypharmacy that are more commonly occurring at younger ages. The aim of this review is to revisit fundamental differences in child-adult thermoregulation in the face of these multifaceted climate challenges, address emerging concerns, and emphasize risk reduction strategies for the health and performance of children in the heat.
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Affiliation(s)
- Caroline J Smith
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA.
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Hydration Status and Cardiovascular Function. Nutrients 2019; 11:nu11081866. [PMID: 31405195 PMCID: PMC6723555 DOI: 10.3390/nu11081866] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/30/2019] [Accepted: 08/08/2019] [Indexed: 02/07/2023] Open
Abstract
Hypohydration, defined as a state of low body water, increases thirst sensations, arginine vasopressin release, and elicits renin–angiotensin–aldosterone system activation to replenish intra- and extra-cellular fluid stores. Hypohydration impairs mental and physical performance, but new evidence suggests hypohydration may also have deleterious effects on cardiovascular health. This is alarming because cardiovascular disease is the leading cause of death in the United States. Observational studies have linked habitual low water intake with increased future risk for adverse cardiovascular events. While it is currently unclear how chronic reductions in water intake may predispose individuals to greater future risk for adverse cardiovascular events, there is evidence that acute hypohydration impairs vascular function and blood pressure (BP) regulation. Specifically, acute hypohydration may reduce endothelial function, increase sympathetic nervous system activity, and worsen orthostatic tolerance. Therefore, the purpose of this review is to present the currently available evidence linking acute hypohydration with altered vascular function and BP regulation.
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Hosokawa Y, Casa DJ, Trtanj JM, Belval LN, Deuster PA, Giltz SM, Grundstein AJ, Hawkins MD, Huggins RA, Jacklitsch B, Jardine JF, Jones H, Kazman JB, Reynolds ME, Stearns RL, Vanos JK, Williams AL, Williams WJ. Activity modification in heat: critical assessment of guidelines across athletic, occupational, and military settings in the USA. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2019; 63:405-427. [PMID: 30710251 PMCID: PMC10041407 DOI: 10.1007/s00484-019-01673-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 01/13/2019] [Accepted: 01/15/2019] [Indexed: 05/04/2023]
Abstract
Exertional heat illness (EHI) risk is a serious concern among athletes, laborers, and warfighters. US Governing organizations have established various activity modification guidelines (AMGs) and other risk mitigation plans to help ensure the health and safety of their workers. The extent of metabolic heat production and heat gain that ensue from their work are the core reasons for EHI in the aforementioned population. Therefore, the major focus of AMGs in all settings is to modulate the work intensity and duration with additional modification in adjustable extrinsic risk factors (e.g., clothing, equipment) and intrinsic risk factors (e.g., heat acclimatization, fitness, hydration status). Future studies should continue to integrate more physiological (e.g., valid body fluid balance, internal body temperature) and biometeorological factors (e.g., cumulative heat stress) to the existing heat risk assessment models to reduce the assumptions and limitations in them. Future interagency collaboration to advance heat mitigation plans among physically active population is desired to maximize the existing resources and data to facilitate advancement in AMGs for environmental heat.
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Affiliation(s)
- Yuri Hosokawa
- Korey Stringer Institute, University of Connecticut, Storrs, CT, USA.
- College of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
| | - Douglas J Casa
- Korey Stringer Institute, University of Connecticut, Storrs, CT, USA
| | - Juli M Trtanj
- National Oceanic and Atmospheric Administration, Washington DC, USA
| | - Luke N Belval
- Korey Stringer Institute, University of Connecticut, Storrs, CT, USA
| | - Patricia A Deuster
- Consortium for Health and Military Performance, Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Sarah M Giltz
- National Oceanic and Atmospheric Administration, Washington DC, USA
- Louisiana Sea Grant, Louisiana State University, Baton Rouge, LA, USA
| | | | | | - Robert A Huggins
- Korey Stringer Institute, University of Connecticut, Storrs, CT, USA
| | - Brenda Jacklitsch
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - John F Jardine
- Korey Stringer Institute, University of Connecticut, Storrs, CT, USA
| | - Hunter Jones
- National Oceanic and Atmospheric Administration, Washington DC, USA
- University Corporation for Atmospheric Research, Boulder, CO, USA
| | - Josh B Kazman
- Consortium for Health and Military Performance, Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Mark E Reynolds
- U.S. Army Public Health Center, Aberdeen Proving Ground, Aberdeen, MD, USA
| | - Rebecca L Stearns
- Korey Stringer Institute, University of Connecticut, Storrs, CT, USA
| | - Jennifer K Vanos
- Scripps Institution of Oceanography Department, University of California San Diego, La Jolla, CA, USA
| | - Alan L Williams
- Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - W Jon Williams
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
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Caldwell AR, Burchfield J, Moyen NE, Tucker MA, Butts CL, Elbin RJ, Ganio MS. Obesity, but not hypohydration, mediates changes in mental task load during passive heating in females. PeerJ 2018; 6:e5394. [PMID: 30128190 PMCID: PMC6098944 DOI: 10.7717/peerj.5394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/16/2018] [Indexed: 12/18/2022] Open
Abstract
Background The independent effects of hypohydration and hyperthermia on cognition and mood is unclear since the two stresses often confound each other. Further, it is unknown if obese individuals have the same impairments during hyperthermia and hypohydration that is often observed in non-obese individuals. Methods The current study was designed to assess the independent and combined effects of mild hypohydration and hyperthermia on cognition, mood, and mental task load in obese and non-obese females. Twenty-one healthy females participated in two passive heating trials, wherein they were either euhydrated or hypohydrated prior to and throughout passive heating. Cognition (ImPACT), mental task load (NASA-TLX), and mood (Brunel Mood Scale; BRUMS) were measured before and after a 1.0 °C increase in core temperature (TC). Results After a 1.0 °C TC elevation, hypohydration resulted in greater (p < 0.05) body mass loss (-1.14 ± 0.48 vs -0.58 ± 0.48 kg; hypohydrated and euhydrated, respectively) and elevation in serum osmolality (292 ± 4 vs 282 ± 3 mOsm; p < 0.05) versus euhydration. Hypohydration, independent of hyperthermia, did not affect mental task load or mood (p > 0.05). Hyperthermia, regardless of hydration status, impaired (∼5 A.U) measures of memory-based cognition (verbal and visual memory), and increased mental task load, while worsening mood (p < 0.05). Interestingly, obese individuals had increased mental task load while hyperthermic compared to the non-obese individuals (p < 0.05) even while euhydrated. Hypohydration did not exacerbate any heat-related effects on cognition between obese and non-obese females (p > 0.05). Conclusion These data indicate that hyperthermia independently impairs memory-based aspects of cognitive performance, mental task load, and leads to a negative mood state. Mild hypohydration did not exacerbate the effects of hyperthermia. However, obese individuals had increased mental task load during hyperthermia.
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Affiliation(s)
- Aaron R Caldwell
- Exercise Science Research Center, University of Arkansas at Fayetteville, Fayetteville, AR, United States of America
| | - Jenna Burchfield
- Exercise Science Research Center, University of Arkansas at Fayetteville, Fayetteville, AR, United States of America
| | - Nicole E Moyen
- Exercise Science Research Center, University of Arkansas at Fayetteville, Fayetteville, AR, United States of America
| | - Matthew A Tucker
- Exercise Science Research Center, University of Arkansas at Fayetteville, Fayetteville, AR, United States of America.,Georgia Prevention Institute, Augusta University, Augusta, GA, United States of America
| | - Cory L Butts
- Exercise Science Research Center, University of Arkansas at Fayetteville, Fayetteville, AR, United States of America
| | - R J Elbin
- Exercise Science Research Center, University of Arkansas at Fayetteville, Fayetteville, AR, United States of America
| | - Matthew S Ganio
- Exercise Science Research Center, University of Arkansas at Fayetteville, Fayetteville, AR, United States of America
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Postsynaptic cutaneous vasodilation and sweating: influence of adiposity and hydration status. Eur J Appl Physiol 2018; 118:1703-1713. [PMID: 29855792 DOI: 10.1007/s00421-018-3902-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/24/2018] [Indexed: 10/14/2022]
Abstract
INTRODUCTION Obesity and hypohydration independently affect postsynaptic endothelial function, but it is unknown if hypohydration affects lean and obese individuals differently. PURPOSE To examine the effect of hypohydration on postsynaptic cutaneous vasodilation and sweating in men with high and low adiposity (HI- and LO-BF, respectively). METHODS Ten males with LO-BF and ten with HI-BF were instrumented for forearm microdialysis when euhydrated and hypohydrated. Changes in cutaneous vascular conductance (CVC) with intradermal infusion of sodium nitroprusside (SNP) and methacholine chloride (MCh) were assessed. Local sweat rate (LSR) was simultaneously assessed at the MCh site. At the end of the last dose, maximal CVC was elicited by delivering a maximal dose of SNP for 30 min to both sites with simultaneous local heating at the SNP site. The concentration of drug needed to elicit 50% of the maximal response (EC50) was compared between groups and hydration conditions. RESULTS When euhydrated, EC50 of MCh-induced CVC was not different between LO- vs. HI-BF [- 3.04 ± 0.12 vs. - 2.98 ± 0.19 log (MCh) M, P = 0.841]. EC50 of SNP-induced CVC was higher in euhydrated HI- vs. LO-BF (- 1.74 ± 0.17 vs. - 2.13 ± 0.06 log (SNP) M, P = 0.034). Within each group, hydration status did not change MCh- or SNP-induced CVC (P > 0.05). LSR was not different between groups or hydration condition (P > 0.05). CONCLUSIONS These data suggest reduced sensitivity of endothelium-independent vasodilation in individuals with high adiposity when euhydrated. However, hypohydration does not affect cutaneous vasodilation or local sweat rate differently between individuals with low or high adiposity.
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Tucker MA, Six A, Moyen NE, Satterfield AZ, Ganio MS. Effect of hypohydration on postsynaptic cutaneous vasodilation and sweating in healthy men. Am J Physiol Regul Integr Comp Physiol 2017; 312:R637-R642. [DOI: 10.1152/ajpregu.00525.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/23/2017] [Accepted: 02/09/2017] [Indexed: 02/05/2023]
Abstract
Hypohydration decreases cutaneous vasodilation and sweating during heat stress, but it is unknown if these decrements are from postsynaptic (i.e., sweat gland/blood vessel) alterations. The purpose of this study was to determine if hypohydration affects postsynaptic cutaneous vasodilation and sweating responses. Twelve healthy men participated in euhydrated (EU) and hypohydrated (HY) trials, with hypohydration induced via fluid restriction and passive heat stress. Changes in cutaneous vascular conductance (CVC; %max) in response to incremental intradermal infusion of the endothelium-independent vasodilator sodium nitroprusside (SNP) and the endothelium-dependent vasodilator methacholine chloride (MCh) were assessed by laser Doppler flowmetry. Local sweat rate (LSR) was simultaneously assessed at the MCh site via ventilated capsule. At the end of the last dose, maximal CVC was elicited by delivering a maximal dose of SNP (5 × 10−2 M) for 30 min to both sites with simultaneous local heating (~44°C) at the SNP site. The concentration of drug needed to elicit 50% of the maximal response (log EC50) was compared between hydration conditions. The percent body mass loss was greater with HY vs. EU (−2.2 ± 0.7 vs. −0.1 ± 0.7%, P < 0.001). Log EC50 of endothelium-dependent CVC was lower with EU (−3.62 ± 0.22) vs. HY (−2.93 ± 0.08; P = 0.044). Hypohydration did not significantly alter endothelium-independent CVC or LSR (both P > 0.05). In conclusion, hypohydration attenuated endothelium-dependent CVC but did not affect endothelium-independent CVC or LSR responses. These data suggest that reductions in skin blood flow accompanying hypohydration can be partially attributed to altered postsynaptic function.
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Affiliation(s)
- Matthew A. Tucker
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
| | - Ashley Six
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
| | - Nicole E. Moyen
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
- Fitbit, San Francisco, California
| | - Alf Z. Satterfield
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
| | - Matthew S. Ganio
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas; and
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Caldwell AR, Tucker MA, Burchfield J, Moyen NE, Satterfield AZ, Six A, McDermott BP, Mulvenon SW, Ganio MS. Hydration status influences the measurement of arterial stiffness. Clin Physiol Funct Imaging 2017; 38:447-454. [DOI: 10.1111/cpf.12436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 03/16/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Aaron R. Caldwell
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
| | - Matthew A. Tucker
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
| | - Jenna Burchfield
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
| | - Nicole E. Moyen
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
| | - Alf Z. Satterfield
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
| | - Ashley Six
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
| | - Brendon P. McDermott
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
| | - Sean W. Mulvenon
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
| | - Matthew S. Ganio
- Human Performance Laboratory; College of Education and Health Professionals; University of Arkansas; Fayetteville AR USA
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