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Zhang B, Li J, Zhou J, Chow L, Zhao G, Huang Y, Ma Z, Zhang Q, Yang Y, Yiu CK, Li J, Chun F, Huang X, Gao Y, Wu P, Jia S, Li H, Li D, Liu Y, Yao K, Shi R, Chen Z, Khoo BL, Yang W, Wang F, Zheng Z, Wang Z, Yu X. A three-dimensional liquid diode for soft, integrated permeable electronics. Nature 2024; 628:84-92. [PMID: 38538792 DOI: 10.1038/s41586-024-07161-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 02/05/2024] [Indexed: 04/05/2024]
Abstract
Wearable electronics with great breathability enable a comfortable wearing experience and facilitate continuous biosignal monitoring over extended periods1-3. However, current research on permeable electronics is predominantly at the stage of electrode and substrate development, which is far behind practical applications with comprehensive integration with diverse electronic components (for example, circuitry, electronics, encapsulation)4-8. Achieving permeability and multifunctionality in a singular, integrated wearable electronic system remains a formidable challenge. Here we present a general strategy for integrated moisture-permeable wearable electronics based on three-dimensional liquid diode (3D LD) configurations. By constructing spatially heterogeneous wettability, the 3D LD unidirectionally self-pumps the sweat from the skin to the outlet at a maximum flow rate of 11.6 ml cm-2 min-1, 4,000 times greater than the physiological sweat rate during exercise, presenting exceptional skin-friendliness, user comfort and stable signal-reading behaviour even under sweating conditions. A detachable design incorporating a replaceable vapour/sweat-discharging substrate enables the reuse of soft circuitry/electronics, increasing its sustainability and cost-effectiveness. We demonstrated this fundamental technology in both advanced skin-integrated electronics and textile-integrated electronics, highlighting its potential for scalable, user-friendly wearable devices.
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Affiliation(s)
- Binbin Zhang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Jiyu Li
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Jingkun Zhou
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Lung Chow
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Guangyao Zhao
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Ya Huang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Zhiqiang Ma
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Qiang Zhang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Yawen Yang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Chun Ki Yiu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Jian Li
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Fengjun Chun
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
| | - Xingcan Huang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Yuyu Gao
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Pengcheng Wu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Shengxin Jia
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Hu Li
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Dengfeng Li
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Yiming Liu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Kuanming Yao
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Rui Shi
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Zhenlin Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Bee Luan Khoo
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China
| | - Weiqing Yang
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Feng Wang
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
| | - Zijian Zheng
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Zuankai Wang
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xinge Yu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
- Hong Kong Centre for Cerebro-cardiovascular Health Engineering, Hong Kong Science Park, Hong Kong, China.
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Ravanelli N, Newhouse D, Foster F, Caldwell AR. Agreement between the ventilated capsule and the KuduSmart® device for measuring sweating responses to passive heat stress and exercise. Appl Physiol Nutr Metab 2023; 48:946-953. [PMID: 37566898 DOI: 10.1139/apnm-2023-0149] [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: 08/13/2023]
Abstract
The present study assessed agreement between a wireless sweat rate monitor (KuduSmart® device) and the ventilated capsule (VC) technique for measuring: (i) minute-averaged local sweat rate (LSR), (ii) sweating onset, (iii) sudomotor thermosensitivity, and (iv) steady-state LSR, during passive heat stress and exercise. It was hypothesized that acceptable agreement with no bias would be observed between techniques for all assessed sweating characteristics. On two separate occasions for each intervention, participants were either passively heated by recirculating hot water (49 °C) through a tube-lined garment until rectal temperature increased 1 °C over baseline (n = 8), or a 60 min treadmill march at a fixed rate of heat production (∼500 W, n = 9). LSR of the forearm was concurrently measured with a VC and the KuduSmart® device secured within ∼2 cm. Using a ratio scale Bland-Altman analysis with the VC as the reference, the KuduSmart® device demonstrated systematic bias and not acceptable agreement for minute-averaged LSR (1.17 [1.09, 1.27], CV = 44.5%), systematic bias and acceptable agreement for steady-state LSR (1.16 [1.09,1.23], CV = 19.5%), no bias and acceptable agreement for thermosensitivity (1.07 [0.99, 1.16], CV = 23.2%), and no bias and good agreement for sweating onset (1.00 [1.00, 1.00], CV = 11.1%). In total, ≥73% of all minute-averaged LSR observations with the KuduSmart® device (n = 2743) were within an absolute error of <0.2 mg/cm2/min to the VC, the reference minimum detectable change in measurement error of a VC on the forearm. Collectively, the KuduSmart® device may be a satisfactory solution for assessing the sweating response to heat stress where a VC is impractical.
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Affiliation(s)
- Nicholas Ravanelli
- School of Kinesiology, Lakehead University, Thunder Bay, ON, Canada
- Centre for Research in Occupational Safety and Health, Laurentian University, Sudbury, ON, Canada
| | - Douglas Newhouse
- School of Kinesiology, Lakehead University, Thunder Bay, ON, Canada
- Centre for Research in Occupational Safety and Health, Laurentian University, Sudbury, ON, Canada
| | - Fergus Foster
- School of Kinesiology, Lakehead University, Thunder Bay, ON, Canada
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Turner O, Mitchell N, Ruddock A, Purvis A, Ranchordas MK. Fluid Balance, Sodium Losses and Hydration Practices of Elite Squash Players during Training. Nutrients 2023; 15:nu15071749. [PMID: 37049589 PMCID: PMC10096645 DOI: 10.3390/nu15071749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 03/30/2023] [Accepted: 04/01/2023] [Indexed: 04/07/2023] Open
Abstract
Elite squash players are reported to train indoors at high volumes and intensities throughout a microcycle. This may increase hydration demands, with hypohydration potentially impairing many key performance indicators which characterise elite squash performance. Consequently, the main aim of this study was to quantify the sweat rates and sweat [Na+] of elite squash players throughout a training session, alongside their hydration practices. Fourteen (males = seven; females = seven) elite or world class squash player’s fluid balance, sweat [Na+] and hydration practices were calculated throughout a training session in moderate environmental conditions (20 ± 0.4 °C; 40.6 ± 1% RH). Rehydration practices were also quantified post-session until the players’ next training session, with some training the same day and some training the following day. Players had a mean fluid balance of −1.22 ± 1.22% throughout the session. Players had a mean sweat rate of 1.11 ± 0.56 L·h−1, with there being a significant difference between male and female players (p < 0.05), and a mean sweat (Na+) of 46 ± 12 mmol·L−1. Players training the following day were able to replace fluid and sodium losses, whereas players training again on the same day were not. These data suggest the variability in players hydration demands and highlight the need to individualise hydration strategies, as well as training prescription, to ensure players with high hydration demands have ample time to optimally rehydrate.
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Affiliation(s)
- Ollie Turner
- Academy of Sport & Physical Activity, Sheffield Hallam University, Sheffield S10 2BP, UK
- English Institute of Sport, Manchester M11 3BS, UK
| | | | - Alan Ruddock
- Academy of Sport & Physical Activity, Sheffield Hallam University, Sheffield S10 2BP, UK
| | - Alison Purvis
- Academy of Sport & Physical Activity, Sheffield Hallam University, Sheffield S10 2BP, UK
| | - Mayur K. Ranchordas
- Academy of Sport & Physical Activity, Sheffield Hallam University, Sheffield S10 2BP, UK
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Badham L, Stern SE, O’Connor FK, Wijekulasuriya GA, Corcoran G, Cox GR, Coffey VG. Fluid intake is a strong predictor of outdoor team sport pre-season training performance. J Sports Sci 2023; 41:1-7. [PMID: 37002685 DOI: 10.1080/02640414.2023.2191093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Our aim was to characterize fluid intake during outdoor team sport training and use generalized additive models to quantify interactions with the environment and performance. Fluid intake, body mass (BM) and internal/external training load data were recorded for male rugby union (n = 19) and soccer (n = 19) athletes before/after field training sessions throughout an 11-week preseason (357 observations). Running performance (GPS) and environmental conditions were recorded each session and generalized additive models were applied in the analysis of data. Mean body mass loss throughout all training sessions was -1.11 ± 0.63 kg (~1.3%) compared with a mean fluid intake at each session of 958 ± 476 mL during the experimental period. For sessions >110 min, when fluid intake reached ~10-19 mL·kg-1 BM the total distance increased (7.47 to 8.06 km, 7.6%; P = 0.049). Fluid intake above ~10 mL·kg-1 BM was associated with a 4.1% increase in high-speed running distance (P < 0.0001). Most outdoor team sport athletes fail to match fluid loss during training, and fluid intake is a strong predictor of running performance. Improved hydration practices during training should be beneficial and we provide a practical ingestion range to promote improved exercise capacity in outdoor team sport training sessions.
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Affiliation(s)
- Luke Badham
- Bond Institute of Health and Sport and Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Steven E. Stern
- Centre for Data Analytics, Bond Business School, Bond University, Gold Coast, Queensland, Australia
| | - Fergus K. O’Connor
- Bond Institute of Health and Sport and Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Gyan A. Wijekulasuriya
- Bond Institute of Health and Sport and Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Glenn Corcoran
- Bond University High Performance Training Centre, Gold Coast, Queensland, Australia
| | - Gregory R. Cox
- Bond Institute of Health and Sport and Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Vernon G. Coffey
- Bond Institute of Health and Sport and Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia
- Centre for Data Analytics, Bond Business School, Bond University, Gold Coast, Queensland, Australia
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Al-Husseini A, Fazel Bakhsheshi M, Gard A, Tegner Y, Marklund N. Shorter recovery time in concussed elite ice hockey players by early head-and-neck cooling - a clinical trial. J Neurotrauma 2022. [PMID: 36222612 DOI: 10.1089/neu.2022.0248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A sports-related concussion (SRC) is most commonly sustained in contact sports, and is defined as a mild traumatic brain injury. An exercise-induced elevation of core body temperature is associated with increased brain temperature that may accelerate secondary injury processes following SRC, and exacerbate the brain injury. In a recent pilot study, acute head-neck cooling of 29 concussed ice hockey players resulted in shorter time to return-to-play. Here, we extended the clinical trial to include players of 19 male elite Swedish ice hockey teams over 5 seasons (2016-2021). In the intervention teams, acute head-neck cooling was implemented using a head cap for ≥45 minutes in addition to the standard SRC management used in controls. The primary endpoint was time from SRC until return-to-play (RTP). Sixty-one SRCs were included in the intervention group and 71 SRCs in the control group. The number of previous SRCs was 2 (median and interquartile range (IQR): 1.0 - 2.0) and 1 (IQR 1.0 - 2.0) in the intervention and control groups, respectively; p= 0.293. Median time to initiate head-neck cooling was 10 min (IQR 7-15; range 5-30 min) and median duration of cooling was 45 min (IQR 45-50; range 45-70 min). The median time to RTP was 9 days in the intervention group (IQR 7-13.5 days) and 13 days in the control group (IQR 9-30; p<0.001). The proportion of players out from play for more than the expected recovery time of 14 days was 24.7% in the intervention group, and 43.7% in controls (p<0.05). Study limitations include that a) allocation to cooling or control management was at the discretion of the medical staff of each teams, decided prior to each season, and not by strict randomization, b) no sham cap was used and evaluations could not be performed by blinded assessors and c) it could not be established with certainty that injury severity was similar between groups. While the results should thus be interpreted with caution, early head-neck cooling, with the aim of attenuating cerebral hyperthermia, may reduce post-SRC symptoms and lead to earlier return-to-play in elite ice hockey players.
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Affiliation(s)
- Ali Al-Husseini
- Lund University, 5193, Department of Clinical Sciences, Neurosurgery, Lund, Sweden;
| | | | - Anna Gard
- Lund University, 5193, Department of Clinical Sciences Lund, Entregatan 7, Hisshall EA, plan 4, Lund, Lund, Skane, Sweden, 22242;
| | - Yelverton Tegner
- Luleå University of Technology, Division of Medical Sciences, Department of Health Sciences, Department of Health Sciences, Luleå, Sweden, SE 971 87;
| | - Niklas Marklund
- Lund University, 5193, Clinical Sciences, Neurosurgery, Klinikgatan 17B, Lund, Sweden, 221 85.,Skåne University Hospital Lund, 59564, Neurosurgery, Lund, Sweden, 221 85;
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Szymanski M, Miller KC, O'Connor P, Hildebrandt L, Umberger L. Sweat Characteristics in Individuals With Varying Susceptibilities of Exercise-Associated Muscle Cramps. J Strength Cond Res 2022; 36:1171-1176. [PMID: 35482541 DOI: 10.1519/jsc.0000000000003605] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Szymanski, M, Miller, KC, O'Connor, P, Hildebrandt, L, and Umberger, L. Sweat characteristics in individuals with varying susceptibilities of exercise-associated muscle cramps. J Strength Cond Res 36(5): 1171-1176, 2022-Many medical professionals believe dehydration and electrolyte losses cause exercise-associated muscle cramping (EAMC). Unlike prior field studies, we compared sweat characteristics in crampers and noncrampers but accounted for numerous factors that affect sweat characteristics including initial hydration status, diet and fluid intake, exercise conditions, and environmental conditions. Sixteen women and 14 men (mean ± SD; age = 21 ± 2 year, body mass = 69.1 ± 11.6 kg, height = 171.4 ± 9.9 cm) self-reported either no EAMC history (n = 8), low EAMC history (n = 10), or high EAMC history (n = 12). We measured V̇o2max, and subjects recorded their diet. At least 3 days later, subjects ran at 70% of their V̇o2max for 30 minutes in the heat (39.9 ± 0.6° C, 36 ± 2% relative humidity). Dorsal forearm sweat was collected and analyzed for sweat sodium concentration ([Na+]sw), sweat potassium concentration ([K+]sw), and sweat chloride concentration ([Cl-]sw). Sweat rate (SWR) was estimated from body mass and normalized using body surface area (BSA). Dietary fluid, Na+, and K+ ingestion was estimated from a 3-day diet log. We observed no differences for any variable among the original 3 groups (p = 0.05-p = 0.73). Thus, we combined the high and low cramp groups and reanalyzed the data against the noncramping group. Again, there were no differences for [Na+]sw (p = 0.68), [K+]sw (p = 0.86), [Cl-]sw, (p = 0.69), SWR/BSA (p = 0.11), dietary Na+ (p = 0.14), dietary K+ (p = 0.66), and fluid intake (p = 0.28). Fluid and electrolyte losses may play a more minor role in EAMC genesis than previously thought.
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Affiliation(s)
- Michael Szymanski
- Central Michigan University, School of Rehabilitation and Medical Sciences, Mount Pleasant, Michigan
| | - Kevin C Miller
- Central Michigan University, School of Rehabilitation and Medical Sciences, Mount Pleasant, Michigan
| | - Paul O'Connor
- Central Michigan University, School of Health Sciences, Mount Pleasant, Michigan; and
| | - Leslie Hildebrandt
- Central Michigan University, College of Education and Human Services, Mount Pleasant, Michigan
| | - Leah Umberger
- Central Michigan University, School of Health Sciences, Mount Pleasant, Michigan; and
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Altuntas A. Hyponatremia: Is it related to the seasons? J Med Biochem 2021; 40:407-413. [PMID: 34616231 PMCID: PMC8451223 DOI: 10.5937/jomb0-30409] [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: 03/23/2021] [Accepted: 04/19/2021] [Indexed: 01/18/2023] Open
Abstract
Background Hyponatremia is a common electrolyte disorder in inpatients related to morbidity and mortality. In this study, we aimed to examine whether there is a relationship between the incidence of hyponatremia and the seasons among the patients hospitalized in our nephrology department. Methods The inpatients in our Nephrology Department between 2012 and 2015 were retrospectively analyzed. The patients with serum sodium levels below 135 mmol/L were included in the study. Hyponatremia incidence was calculated as the proportion of inpatients with low sodium levels in a season to the total number of inpatients in the same season. Results Out of 1950 inpatients in four years, 509 were found to have hyponatremia (26.1%). The mean serum sodium level of the patients was 129.7±4.7 mmol/L. Hyponatremia incidences in autumn, winter, spring, and summer were found to be 28.7%, 15.4%, 20.4%, and 36.6%, respectively. Upon comparing the incidence of hyponatremia in patients hospitalized in winter and summer seasons, there was a significantly higher incidence of hyponatremia in summer (p<0.001). We found a positive correlation between hyponatremia incidence and temperature (r=0.867, p=0.001). However, there was a negative correlation between hyponatremia incidence and relative humidity (r=-0.735, p=0.001). Conclusions The highest hyponatremia incidence was observed in summer in a four-year period. Loss of sodium by perspiration, along with increased temperature and/or excessive hypotonic fluid intake, might contribute to the development of hyponatremia.
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Affiliation(s)
- Atila Altuntas
- Suleyman Demirel University, Faculty of Medicine, Department of Internal Medicine, Division of Nephrology, Isparta, Turkey
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Lopez RM, Ashley CD, Zinder SM, Tritsch AJ. Thermoregulation and Hydration in Female American Football Players During Practices. J Strength Cond Res 2021; 35:2552-2557. [PMID: 31045683 DOI: 10.1519/jsc.0000000000003180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Lopez, RM, Ashley, CD, Zinder, SM, and Tritsch, AJ. Thermoregulation and hydration in female American football players during practices. J Strength Cond Res 35(9): 2552-2557, 2021-Little is known about hydration practices and thermoregulation in female tackle football players. The purpose of the study was to examine the thermoregulatory and hydration responses of female professional American football players. Fifteen females from the same tackle football team volunteered for this observational field study. Each subject was observed for 4 practices for the following measures: gastrointestinal temperature (TGI), maximum TGI, heart rate (HR), maximum HR (HRmax), fluid consumption, sweat rate, percent body mass loss (%BML), urine specific gravity (USG), urine color (Ucol), perceptual measures of thirst, thermal sensations, and rating of perceived exertion (RPE). Descriptive data (mean ± SD) were calculated for all measures. Main measures were analyzed using a repeated-measures analysis of variance. Trials took place during evening practices. Average TGI during practices was 38.0 ± 0.3° C while maximum TGI was 38.4 ± 0.3° C (n = 14). Average practice HR was 118 ± 11 b·min-1, while HRmax was 148 ± 13 b·min-1. Subjects arrived at practices with Ucol of 3 ± 1 and USG of 1.018 ± 0.007. Postpractice USG (1.022 ± 0.007) was significantly higher than prepractice across all days (p < 0.001). The average sweat rate across 4 practices was 0.6 ml·h-1. Average %BML was 0.3 ± 0.4%. Thirst and thermal sensations were moderate (4 ± 1 and 5 ± 1, respectively), while RPE was 11 ± 1. Female football players tended to have similar physiological responses to males. Although subjects seemed to adequately match their sweat losses with fluid consumed during practice, there was considerable variability in hydration indices and hydration habits, with some subjects experiencing hypohydration and others overestimating their fluid needs. Those working with this population should emphasize the need for hydration education and establish individualized hydration regimens.
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Affiliation(s)
| | - Candi D Ashley
- Educational and Psychological Studies, University of South Florida, Tampa, Florida; and
| | - Steven M Zinder
- School of Health and Applied Human Sciences, University of North Carolina, Wilmington, North Carolina
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Chen YC, Shan SS, Liao YT, Liao YC. Bio-inspired fractal textile device for rapid sweat collection and monitoring. LAB ON A CHIP 2021; 21:2524-2533. [PMID: 34105558 DOI: 10.1039/d1lc00328c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this study, a new design concept in sweat collection was developed to achieve rapid and intact sweat sampling for analytical purposes. Textiles with fast water wicking properties were first selected and laser engraved into tree-like bifurcating channels for sweat collection. The fractal framework of the bifurcating textile channels was theoretically derived to minimize the flow resistance for fast sweat absorption. The optimized collector with designed fractal geometry exhibited thorough coverage of emerging droplets without overflow. Great collection efficiency was achieved with a short induction time (<1 minute after perspiration begins) and a maximum sweat collection flux up to 4.0 μL cm-2 min-1 without leakage. After being combined with printed sensors and microchips, the assembled sweat collection/sensing device can simultaneously provide measurements of salt concentration and sweat rate for wireless hydration state monitoring. The collection/sensing system also exhibited fast response times to abrupt changes in sweat rates or concentrations and thus can be used to detect instant physical conditions in exercise. Finally, field tests were performed to demonstrate the reliability and practicality of the device in real-time sweat monitoring under vigorous activities.
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Affiliation(s)
- Yen-Chi Chen
- Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan. and Advanced Research Center for Green Materials Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Siang-Sin Shan
- Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Yu-Te Liao
- Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Ying-Chih Liao
- Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan. and Advanced Research Center for Green Materials Science and Technology, National Taiwan University, Taipei, Taiwan
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Normative Data for Sweat Rate and Whole-Body Sodium Concentration in Athletes Indigenous to Tropical Climate. Int J Sport Nutr Exerc Metab 2020; 30:264-271. [PMID: 32454460 DOI: 10.1123/ijsnem.2019-0299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 03/25/2020] [Accepted: 03/25/2020] [Indexed: 11/18/2022]
Abstract
This study determined normative data for sweat rate (SR) and whole-body (WB) sweat sodium concentration [Na+] in athletes indigenous to a tropical climate, categorized by age, gender, and sport classification. We analyzed data from 556 athletes (386 adult and 170 young) in endurance (END), team/ball (TBA), and combat (COM) sports exercising in tropical environments (wet bulb globe temperature = 29.4 ± 2.1 °C). SR was calculated from change in body weight corrected for urine output and fluid/food intake. Sweat was collected using absorbent patches, and regional [Na+] was determined using an ion selective analyzer and normalized to WB sweat [Na+]. Data are expressed as mean ± SD. SR was higher in males compared with females in both young (24.2 ± 7.7 ml·kg-1·hr-1 vs. 16.7 ± 5.7 ml·kg-1·hr-1) and adult (22.8 ± 7.4 ml·kg-1·hr-1 vs. 18.6 ± 7.0 ml·kg-1·hr-1) athletes, in END sports in girls (END = 19.1 ± 6.0 ml·kg-1·hr-1; TBA = 14.6 ± 4.5 ml·kg-1·hr-1), and in adult males (END = 25.2 ± 6.3 ml·kg-1·hr-1; TBA = 19.1 ± 7.2 ml·kg-1·hr-1; COM = 18.4 ± 8.5 ml·kg-1·hr-1) and females (END = 23.5 ± 5.6 ml·kg-1·hr-1; TBA = 14.2 ± 5.2 ml·kg-1·hr-1; COM = 15.3 ± 5.2 ml·kg-1·hr-1); p < .05. WB sweat [Na+] was higher in adult athletes than in young athletes (43 ± 10 mmol/L vs. 40 ± 9 mmol/L, p < .05). These norms provide a reference range for low, low average, average high, and high SR and WB sweat [Na+], which serve as a guide for fluid replacement for athletes who live and train in the tropics.
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Kim K, Kim B, Lee CH. Printing Flexible and Hybrid Electronics for Human Skin and Eye-Interfaced Health Monitoring Systems. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1902051. [PMID: 31298450 DOI: 10.1002/adma.201902051] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/02/2019] [Indexed: 05/27/2023]
Abstract
Advances in printing materials and techniques for flexible and hybrid electronics in the domain of connected healthcare have enabled rapid development of innovative body-interfaced health monitoring systems at a tremendous pace. Thin, flexible, and stretchable biosensors that are printed on a biocompatible soft substrate provide the ability to noninvasively and unobtrusively integrate with the human body for continuous monitoring and early detection of diseases and other conditions affecting health and well being. Hybrid integration of such biosensors with extremely well-established silicon-based microcircuit chips offers a viable route for in-sensor data processing and wireless transmission in many medical and clinical settings. Here, a set of advanced and hybrid printing techniques is summarized, covering diverse aspects ranging from active electronic materials to process capability, for their use in human skin and eye-interfaced health monitoring systems with different levels of complexity. Essential components of the devices, including constituent biomaterials, structural layouts, assembly methods, and power and data processing configurations, are outlined and discussed in a categorized manner tailored to specific clinical needs. Perspectives on the benefits and challenges of these systems in basic and applied biomedical research are presented and discussed.
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Affiliation(s)
- Kyunghun Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Bongjoong Kim
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Chi Hwan Lee
- Weldon School of Biomedical Engineering, School of Mechanical Engineering, Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN, 47907, USA
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12
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Physiological mechanisms determining eccrine sweat composition. Eur J Appl Physiol 2020; 120:719-752. [PMID: 32124007 PMCID: PMC7125257 DOI: 10.1007/s00421-020-04323-7] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/11/2020] [Indexed: 02/08/2023]
Abstract
Purpose The purpose of this paper is to review the physiological mechanisms determining eccrine sweat composition to assess the utility of sweat as a proxy for blood or as a potential biomarker of human health or nutritional/physiological status. Methods This narrative review includes the major sweat electrolytes (sodium, chloride, and potassium), other micronutrients (e.g., calcium, magnesium, iron, copper, zinc, vitamins), metabolites (e.g., glucose, lactate, ammonia, urea, bicarbonate, amino acids, ethanol), and other compounds (e.g., cytokines and cortisol). Results Ion membrane transport mechanisms for sodium and chloride are well established, but the mechanisms of secretion and/or reabsorption for most other sweat solutes are still equivocal. Correlations between sweat and blood have not been established for most constituents, with perhaps the exception of ethanol. With respect to sweat diagnostics, it is well accepted that elevated sweat sodium and chloride is a useful screening tool for cystic fibrosis. However, sweat electrolyte concentrations are not predictive of hydration status or sweating rate. Sweat metabolite concentrations are not a reliable biomarker for exercise intensity or other physiological stressors. To date, glucose, cytokine, and cortisol research is too limited to suggest that sweat is a useful surrogate for blood. Conclusion Final sweat composition is not only influenced by extracellular solute concentrations, but also mechanisms of secretion and/or reabsorption, sweat flow rate, byproducts of sweat gland metabolism, skin surface contamination, and sebum secretions, among other factors related to methodology. Future research that accounts for these confounding factors is needed to address the existing gaps in the literature. Electronic supplementary material The online version of this article (10.1007/s00421-020-04323-7) contains supplementary material, which is available to authorized users.
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13
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Pryor RR, Pryor JL, Vandermark LW, Adams EL, Brodeur RM, Armstrong LE, Lee EC, Maresh CM, Anderson JM, Casa DJ. Exacerbated heat strain during consecutive days of repeated exercise sessions in heat. J Sci Med Sport 2019; 22:1084-1089. [DOI: 10.1016/j.jsams.2019.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/10/2019] [Accepted: 06/13/2019] [Indexed: 10/26/2022]
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Taylor J, Miller KC. Precooling, Hyperthermia, and Postexercise Cooling Rates in Humans Wearing American Football Uniforms. J Athl Train 2019; 54:758-764. [PMID: 31343276 DOI: 10.4085/1062-6050-175-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Exertional heatstroke is one of the leading causes of death in American football players. Precooling (PC) with whole-body cold-water immersion (CWI) may prevent severe hyperthermia and, possibly, exertional heatstroke. However, it is unknown how much PC delays severe hyperthermia when participants wear American football uniforms during exercise in the heat. Does PC alter the effectiveness of CWI once participants become hyperthermic or affect perceptual variables during exercise? OBJECTIVES We asked 3 questions: (1) Does PC affect how quickly participants become hyperthermic during exercise in the heat? (2) Does PC before exercise affect rectal temperature (Trec) cooling rates once participants become hyperthermic? (3) Does PC affect perceptual variables such as rating of perceived exertion (RPE), thermal sensation, and environmental symptoms questionnaire (ESQ) responses? DESIGN Crossover study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Twelve physically active males (age = 24 ± 4 years, height = 181.8 ± 8.4 cm, mass = 79.9 ± 10.3 kg). INTERVENTION(S) On PC days, participants completed 15 minutes of CWI (9.98°C ± 0.04°C). They donned American football uniforms and exercised in the heat (temperature = 39.1°C ± 0.3°C, relative humidity = 36% ± 2%) until Trec was 39.5°C. While wearing equipment, they then underwent CWI until Trec was 38°C. Control-day procedures were the same except for the PC intervention. MAIN OUTCOME MEASURE(S) Rectal temperature, heart rate, thermal sensation, RPE, and ESQ responses were measured throughout testing. The duration of cold-water immersion was used in conjunction with Trec to calculate cooling rates. RESULTS Precooling allowed participants to exercise 17.6 ± 3.6 minutes longer before reaching 39.5°C (t11 = 17.0, P < .001). Precooling did not affect postexercise CWI Trec cooling rates (PC = 0.18°C/min ± 0.06°C/min, control = 0.20°C/min ± 0.09°C/min; t11 = 0.9, P = .17); ESQ responses (F2,24 = 1.3, P = .3); or RPE (F2,22 = 2.9, P = .07). Precooling temporarily lowered thermal sensation (F3,26 = 21.7, P < .001) and heart rate (F3,29 = 21.0, P < .001) during exercise. CONCLUSIONS Because PC delayed hyperthermia without negatively affecting perceptual variables or CWI effectiveness, clinicians may consider implementing PC along with other proven strategies for preventing heat illness (eg, acclimatization).
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Affiliation(s)
- Jeremy Taylor
- School of Rehabilitation and Medical Sciences, Central Michigan University, Mount Pleasant
| | - Kevin C Miller
- School of Rehabilitation and Medical Sciences, Central Michigan University, Mount Pleasant
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Chen XM, Li YJ, Han D, Zhu HC, Xue CD, Chui HC, Cao T, Qin KR. A Capillary-Evaporation Micropump for Real-Time Sweat Rate Monitoring with an Electrochemical Sensor. MICROMACHINES 2019; 10:mi10070457. [PMID: 31284628 PMCID: PMC6680474 DOI: 10.3390/mi10070457] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 06/23/2019] [Accepted: 06/24/2019] [Indexed: 01/05/2023]
Abstract
Sweat collection and real time monitoring of sweat rate play essential roles in physiology monitoring and assessment of an athlete’s performance during exercise. In this paper, we report a micropump for sweat simulant collection based on the capillary–evaporation effect. An electrochemical sensor is integrated into the micropump, which monitors the flow rate in real-time by detecting the current using three electrodes. The evaporation rate from micropore array, equivalent to the sweat rate, was theoretically and numerically investigated. The designed micropump yields the maximum collection rate as high as 0.235 μL/min. In addition, the collection capability of the micropump was validated experimentally; the flow rate through the microchannel was further detected in real-time with the electrochemical sensor. The experimental maximum collection rate showed good consistency with the theoretical data. Our proposed device shows the potential for sweat collection and real-time monitoring of sweat rate, which is a promising candidate for being a wearable platform for real-time physiology and performance monitoring during exercise.
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Affiliation(s)
- Xiao-Ming Chen
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China
| | - Yong-Jiang Li
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China
| | - Dan Han
- School of Biomedical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Hui-Chao Zhu
- School of Biomedical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Chun-Dong Xue
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China
| | - Hsiang-Chen Chui
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China
| | - Tun Cao
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China.
| | - Kai-Rong Qin
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, China.
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Hew-Butler T, Smith-Hale V, Pollard-McGrandy A, VanSumeren M. Of Mice and Men-The Physiology, Psychology, and Pathology of Overhydration. Nutrients 2019; 11:nu11071539. [PMID: 31284689 PMCID: PMC6682940 DOI: 10.3390/nu11071539] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/28/2019] [Accepted: 07/03/2019] [Indexed: 12/20/2022] Open
Abstract
The detrimental effects of dehydration, to both mental and physical health, are well-described. The potential adverse consequences of overhydration, however, are less understood. The difficulty for most humans to routinely ingest ≥2 liters (L)-or "eight glasses"-of water per day highlights the likely presence of an inhibitory neural circuit which limits the deleterious consequences of overdrinking in mammals but can be consciously overridden in humans. This review summarizes the existing data obtained from both animal (mostly rodent) and human studies regarding the physiology, psychology, and pathology of overhydration. The physiology section will highlight the molecular strength and significance of aquaporin-2 (AQP2) water channel downregulation, in response to chronic anti-diuretic hormone suppression. Absence of the anti-diuretic hormone, arginine vasopressin (AVP), facilitates copious free water urinary excretion (polyuria) in equal volumes to polydipsia to maintain plasma tonicity within normal physiological limits. The psychology section will highlight reasons why humans and rodents may volitionally overdrink, likely in response to anxiety or social isolation whereas polydipsia triggers mesolimbic reward pathways. Lastly, the potential acute (water intoxication) and chronic (urinary bladder distension, ureter dilation and hydronephrosis) pathologies associated with overhydration will be examined largely from the perspective of human case reports and early animal trials.
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Affiliation(s)
- Tamara Hew-Butler
- Division of Kinesiology, Health and Sport Studies, Wayne State University, Detroit, MI 48202, USA.
| | - Valerie Smith-Hale
- Division of Kinesiology, Health and Sport Studies, Wayne State University, Detroit, MI 48202, USA
| | - Alyssa Pollard-McGrandy
- Division of Kinesiology, Health and Sport Studies, Wayne State University, Detroit, MI 48202, USA
| | - Matthew VanSumeren
- Division of Kinesiology, Health and Sport Studies, Wayne State University, Detroit, MI 48202, USA
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17
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Barnes KA, Anderson ML, Stofan JR, Dalrymple KJ, Reimel AJ, Roberts TJ, Randell RK, Ungaro CT, Baker LB. Normative data for sweating rate, sweat sodium concentration, and sweat sodium loss in athletes: An update and analysis by sport. J Sports Sci 2019; 37:2356-2366. [DOI: 10.1080/02640414.2019.1633159] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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18
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Muth T, Pritchett R, Pritchett K, Depaepe J, Blank R. Hydration Status and Perception of Fluid Loss in Male and Female University Rugby Union Players. INTERNATIONAL JOURNAL OF EXERCISE SCIENCE 2019; 12:859-870. [PMID: 31156752 PMCID: PMC6533089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Rugby union players are at risk for dehydration due to the high physiologic demand of the sport (~7.5 MJ/game). Dehydration could be due to lack of knowledge of fluid lost during activity. Therefore, the purpose of this study was to observe the hydration status and sweat loss estimations of male and female university rugby union players over three consecutive training sessions. Body mass, urine specific gravity (USG), and self-reported thirst scores were recorded pre and post training sessions. Sweat loss estimations were recorded post training session. After estimations, participants were shown his or her actual sweat loss in hopes of improving estimations over the three sessions. Paired t-tests were used to determine significance between pre and post training USG, thirst level and body mass for each day. A general linear mixed-effect model was used to determine significance of the difference between variables within gender and within days. Mean body mass changes did not exceed 2% lost for either gender on any of the three training sessions. Males significantly underestimated sweat loss by ~81% (p<0.01) after session one and improved estimations to ~36% after session three, however still significantly underestimated (p<0.01). Females also significantly underestimated sweat loss by ~64% on day one (p<0.01), and also improved estimations to ~60% on day three, however, still significantly underestimated (p<0.01). Results indicate that, on average, the participants remained in a euhydrated state throughout the training sessions. Findings also show that through education participants can improve perceptions of sweat loss to remain in euhydrated state.
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Affiliation(s)
- Trev Muth
- Department of Health Sciences, Central Washington University, Ellensburg, WA, USA
| | - Robert Pritchett
- Department of Health Sciences, Central Washington University, Ellensburg, WA, USA
| | - Kelly Pritchett
- Department of Health Sciences, Central Washington University, Ellensburg, WA, USA
| | - James Depaepe
- Department of Health Sciences, Central Washington University, Ellensburg, WA, USA
| | - Rachael Blank
- Department of Health Sciences, Central Washington University, Ellensburg, WA, USA
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19
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Belanger M, Katapally TR, Barnett TA, O'Loughlin E, Sabiston CM, O'Loughlin J. Link between Physical Activity Type in Adolescence and Body Composition in Adulthood. Med Sci Sports Exerc 2019; 50:709-714. [PMID: 29210917 DOI: 10.1249/mss.0000000000001503] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We investigated whether type of physical activity (PA) (sports, running, and fitness/dance) engaged in during adolescence is associated with body composition in late adolescence or early adulthood. METHODS Data were drawn from 631 participants in the Nicotine Dependence in Teens study, a prospective investigation of students ages 12-13 yr at inception. Self-report PA data were collected at baseline, in grade 7, and every 3-4 months thereafter during the 5 yr of high school (1999-2005). Anthropometric indicators (height, weight, waist circumference, triceps, and subscapular skinfold thickness) were measured at ages 12, 16, and 24 yr. On the basis of prior exploratory factor analysis, PA was categorized into one of three types (sports, running, and fitness/dance). Regression models estimated the association between number of years participating in each PA type (0-5 yr) during high school and body composition measures in later adolescence or early adulthood. RESULTS In multivariable models accounting for age, sex, and parent education, more number of years participating in running during adolescence was associated with lower body mass index, waist circumference, and skinfold thickness in later adolescence and early adulthood (all P < 0.01). This association was no longer apparent in models that accounted for body composition at age 12 yr. The number of years participating in sports was positively associated with body mass index in early adulthood (P = 0.02), but fitness/dance was not statistically significantly associated with any outcome. CONCLUSION Sustaining participation in running, but not in other PA types, during adolescence was related to lower body composition in later adolescence and adulthood. However, more research is needed to determine whether this association is attributable to a relationship between PA and body composition in early adolescence.
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Affiliation(s)
- Mathieu Belanger
- Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA.,Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA.,Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA
| | - Tarun R Katapally
- Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA.,Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA
| | - Tracie A Barnett
- Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA.,Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA
| | - Erin O'Loughlin
- Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA.,Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA
| | - Catherine M Sabiston
- Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA
| | - Jennifer O'Loughlin
- Department of Family Medicine and Emergency Medicine, Université de Sherbrooke, Sherbrooke, QC, CANADA
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20
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Bandodkar AJ, Gutruf P, Choi J, Lee K, Sekine Y, Reeder JT, Jeang WJ, Aranyosi AJ, Lee SP, Model JB, Ghaffari R, Su CJ, Leshock JP, Ray T, Verrillo A, Thomas K, Krishnamurthi V, Han S, Kim J, Krishnan S, Hang T, Rogers JA. Battery-free, skin-interfaced microfluidic/electronic systems for simultaneous electrochemical, colorimetric, and volumetric analysis of sweat. SCIENCE ADVANCES 2019; 5:eaav3294. [PMID: 30746477 PMCID: PMC6357758 DOI: 10.1126/sciadv.aav3294] [Citation(s) in RCA: 295] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/06/2018] [Indexed: 05/13/2023]
Abstract
Wearable sweat sensors rely either on electronics for electrochemical detection or on colorimetry for visual readout. Non-ideal form factors represent disadvantages of the former, while semiquantitative operation and narrow scope of measurable biomarkers characterize the latter. Here, we introduce a battery-free, wireless electronic sensing platform inspired by biofuel cells that integrates chronometric microfluidic platforms with embedded colorimetric assays. The resulting sensors combine advantages of electronic and microfluidic functionality in a platform that is significantly lighter, cheaper, and smaller than alternatives. A demonstration device simultaneously monitors sweat rate/loss, pH, lactate, glucose, and chloride. Systematic studies of the electronics, microfluidics, and integration schemes establish the key design considerations and performance attributes. Two-day human trials that compare concentrations of glucose and lactate in sweat and blood suggest a potential basis for noninvasive, semi-quantitative tracking of physiological status.
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Affiliation(s)
- Amay J. Bandodkar
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
| | - Philipp Gutruf
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85721, USA
| | - Jungil Choi
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
| | - KunHyuck Lee
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yurina Sekine
- Materials Sciences Research Center, Japan Atomic Energy Agency Tokai, Ibaraki 319-1195, Japan
| | - Jonathan T. Reeder
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
| | - William J. Jeang
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
| | - Alexander J. Aranyosi
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
- Epicore Biosystems Inc., Cambridge, MA 02139, USA
| | - Stephen P. Lee
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
- Epicore Biosystems Inc., Cambridge, MA 02139, USA
| | - Jeffrey B. Model
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
- Epicore Biosystems Inc., Cambridge, MA 02139, USA
| | - Roozbeh Ghaffari
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
- Epicore Biosystems Inc., Cambridge, MA 02139, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Chun-Ju Su
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - John P. Leshock
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Tyler Ray
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
| | - Anthony Verrillo
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Kyle Thomas
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Vaishnavi Krishnamurthi
- Functional Material and Microsystems Research Group and Micro Nano Research Facility, RMIT University, Melbourne, Victoria 3000, Australia
| | - Seungyong Han
- Department of Mechanical Engineering, Ajou University, San 5, Woncheon-Dong, Yeongtong-Gu, Suwon 16499, Republic of Korea
| | - Jeonghyun Kim
- Department of Electronics Convergence Engineering, Kwangwoon University, Seoul 01897, Republic of Korea
| | - Siddharth Krishnan
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tao Hang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - John A. Rogers
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Bio-Integrated Electronics, Simpson Querrey Institute for BioNanotechnology, Northwestern University, Evanston, IL 60208, USA
- Epicore Biosystems Inc., Cambridge, MA 02139, USA
- Department of Electronics Convergence Engineering, Kwangwoon University, Seoul 01897, Republic of Korea
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Feinberg School of Medicine, Northwestern University, Evanston, IL 60208, USA
- Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA
- Department of Neurological Surgery, Northwestern University, Evanston, IL 60208, USA
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
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Sekiguchi Y, Adams WM, Curtis RM, Benjamin CL, Casa DJ. Factors influencing hydration status during a National Collegiate Athletics Association division 1 soccer preseason. J Sci Med Sport 2018; 22:624-628. [PMID: 30587437 DOI: 10.1016/j.jsams.2018.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 09/29/2018] [Accepted: 12/08/2018] [Indexed: 11/18/2022]
Abstract
OBJECTIVES To investigate the roles that training load and environmental conditions have on fluid balance during a collegiate men's soccer preseason. DESIGN Observational study. METHODS Twenty-eight male collegiate soccer players (mean±SD; age, 20±1.7y; body mass (BM), 79.9±7.3kg; height, 180.9±6.8cm; body fat, 12.7±3.1%; VO2max, 50.7±4.3ml·kg-1·min-1) participated in this study. Prior to (PRE) and following (POST) each team session, BM, percent BM loss (%BML) and hydration status was measured. Participants donned a heart rate and GPS enabled monitor to measure training load. For all team activities, ambient temperature (TAMB) and relative humidity (RH) were obtained from the nearest local weather station. Participants consumed 500mL of water as part of the team-based hydration strategy before and after training session. Stepwise linear regression was used to identify the variables that predicted %BML. Significance was set a-priori p<0.05. RESULTS Total distance covered predicted %BML during all preseason activities (r2=0.253, p<0.001), with TAMB and RH further adding to the model (r2=0.302, p<0.001). %BML never exceeded 2% of BM during any one session and daily variation in BM was <1% from baseline measures. Urine specific gravity was greater than 1.020 on 12/15days and UCOL was above 4 on 13/15days, indicating a state of hypohydration. CONCLUSIONS Total distance covered was the best predictor for the extent of body water losses during a collegiate preseason. While the team-based hydration strategy during preseason was successful in minimizing fluid losses during activity, participants arrived hypohydrated 80% of the time, necessitating a greater focus on daily fluid needs.
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Affiliation(s)
- Yasuki Sekiguchi
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, USA.
| | - William M Adams
- Department of Kinesiology, University of North Carolina at Greensboro, USA
| | - Ryan M Curtis
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, USA
| | - Courteney L Benjamin
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, USA
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, USA
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Black KE, Black AD, Baker D, Fairbairn K. Body mass changes during training in elite rugby union: Is a single test of hydration indices reliable? Eur J Sport Sci 2018; 18:1049-1057. [PMID: 29806987 DOI: 10.1080/17461391.2018.1470677] [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] [Indexed: 10/14/2022]
Abstract
There is limited research studying fluid and electrolyte balance in rugby union players, and a paucity of information regarding the test-retest reliability. This study describes the fluid balance of elite rugby union players across multiple squads and the reliability of fluid balance measures between two equivalent training sessions. Sixty-one elite rugby players completed a single fluid balance testing session during a game simulation training session. A subsample of 21 players completed a second fluid balance testing session during an equivalent training session. Players were weighed in minimal clothing before and after each training session. Each player was provided with their own drinks which were weighed before and after each training session. More players gained body weight (9 (14.8%)) during training than lost greater than 2% of their initial body mass (1 (1.6%)). Pre-training body mass and rate of fluid loss were significantly associated (r = 0.318, p = .013). There was a significant correlation between rate of fluid loss in sessions 1 (1.74 ± 0.32 L h-1) and 2 (1.10 ± 0.31 L. h-1), (r = 0.470, p = .032). This could be useful for nutritionists working with rugby squads to identify players with high sweat losses.
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Affiliation(s)
| | | | - Dane Baker
- c Chiefs Super Franchise , Hamilton , New Zealand
| | - Kirsty Fairbairn
- d Advanced Sports Dietitian , Invigorate Nutrition , Dunedin , New Zealand
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Sweating Rate and Sweat Sodium Concentration in Athletes: A Review of Methodology and Intra/Interindividual Variability. Sports Med 2018; 47:111-128. [PMID: 28332116 PMCID: PMC5371639 DOI: 10.1007/s40279-017-0691-5] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Athletes lose water and electrolytes as a consequence of thermoregulatory sweating during exercise and it is well known that the rate and composition of sweat loss can vary considerably within and among individuals. Many scientists and practitioners conduct sweat tests to determine sweat water and electrolyte losses of athletes during practice and competition. The information gleaned from sweat testing is often used to guide personalized fluid and electrolyte replacement recommendations for athletes; however, unstandardized methodological practices and challenging field conditions can produce inconsistent/inaccurate results. The primary objective of this paper is to provide a review of the literature regarding the effect of laboratory and field sweat-testing methodological variations on sweating rate (SR) and sweat composition (primarily sodium concentration [Na+]). The simplest and most accurate method to assess whole-body SR is via changes in body mass during exercise; however, potential confounding factors to consider are non-sweat sources of mass change and trapped sweat in clothing. In addition, variability in sweat [Na+] can result from differences in the type of collection system used (whole body or localized), the timing/duration of sweat collection, skin cleaning procedure, sample storage/handling, and analytical technique. Another aim of this paper is to briefly review factors that may impact intra/interindividual variability in SR and sweat [Na+] during exercise, including exercise intensity, environmental conditions, heat acclimation, aerobic capacity, body size/composition, wearing of protective equipment, sex, maturation, aging, diet, and/or hydration status. In summary, sweat testing can be a useful tool to estimate athletes’ SR and sweat Na+ loss to help guide fluid/electrolyte replacement strategies, provided that data are collected, analyzed, and interpreted appropriately.
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Nuccio RP, Barnes KA, Carter JM, Baker LB. Fluid Balance in Team Sport Athletes and the Effect of Hypohydration on Cognitive, Technical, and Physical Performance. Sports Med 2017; 47:1951-1982. [PMID: 28508338 PMCID: PMC5603646 DOI: 10.1007/s40279-017-0738-7] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sweat losses in team sports can be significant due to repeated bursts of high-intensity activity, as well as the large body size of athletes, equipment and uniform requirements, and environmental heat stress often present during training and competition. In this paper we aimed to: (1) describe sweat losses and fluid balance changes reported in team sport athletes, (2) review the literature assessing the impact of hypohydration on cognitive, technical, and physical performance in sports-specific studies, (3) briefly review the potential mechanisms by which hypohydration may impact team sport performance, and (4) discuss considerations for future directions. Significant hypohydration (mean body mass loss (BML) >2%) has been reported most consistently in soccer. Although American Football, rugby, basketball, tennis, and ice hockey have reported high sweating rates, fluid balance disturbances have generally been mild (mean BML <2%), suggesting that drinking opportunities were sufficient for most athletes to offset significant fluid losses. The effect of hydration status on team sport performance has been studied mostly in soccer, basketball, cricket, and baseball, with mixed results. Hypohydration typically impaired performance at higher levels of BML (3-4%) and when the method of dehydration involved heat stress. Increased subjective ratings of fatigue and perceived exertion consistently accompanied hypohydration and could explain, in part, the performance impairments reported in some studies. More research is needed to develop valid, reliable, and sensitive sport-specific protocols and should be used in future studies to determine the effects of hypohydration and modifying factors (e.g., age, sex, athlete caliber) on team sport performance.
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Affiliation(s)
- Ryan P Nuccio
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA.
| | - Kelly A Barnes
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
| | - James M Carter
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
| | - Lindsay B Baker
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
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McDermott BP, Anderson SA, Armstrong LE, Casa DJ, Cheuvront SN, Cooper L, Kenney WL, O'Connor FG, Roberts WO. National Athletic Trainers' Association Position Statement: Fluid Replacement for the Physically Active. J Athl Train 2017; 52:877-895. [PMID: 28985128 PMCID: PMC5634236 DOI: 10.4085/1062-6050-52.9.02] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To present evidence-based recommendations that promote optimized fluid-maintenance practices for physically active individuals. BACKGROUND Both a lack of adequate fluid replacement (hypohydration) and excessive intake (hyperhydration) can compromise athletic performance and increase health risks. Athletes need access to water to prevent hypohydration during physical activity but must be aware of the risks of overdrinking and hyponatremia. Drinking behavior can be modified by education, accessibility, experience, and palatability. This statement updates practical recommendations regarding fluid-replacement strategies for physically active individuals. RECOMMENDATIONS Educate physically active people regarding the benefits of fluid replacement to promote performance and safety and the potential risks of both hypohydration and hyperhydration on health and physical performance. Quantify sweat rates for physically active individuals during exercise in various environments. Work with individuals to develop fluid-replacement practices that promote sufficient but not excessive hydration before, during, and after physical activity.
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Negaard M, Anthony C, Bonthius D, Jepson M, Marcussen B, Pelzer D, Peterson A. A case report: Glycopyrrolate for treatment of exercise-induced hyperhidrosis. SAGE Open Med Case Rep 2017; 5:2050313X17721601. [PMID: 28835822 PMCID: PMC5557159 DOI: 10.1177/2050313x17721601] [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: 02/06/2017] [Accepted: 06/21/2017] [Indexed: 11/30/2022] Open
Abstract
Objective: Hyperhidrosis can cause dehydration and exercise intolerance. There are several case reports of extremely high sweat rates in athletes. We present as case report of a 17-year-old male with the highest sweat rate recorded in the literature (5.8 L/h). Our goal was to determine if glycopyrrolate, an anticholinergic medication with primarily anti-muscarinic effects that is known to decrease sweat production, would reduce the sweat rate of our subject in a controlled exercise setting. Methods: Our patient and a control subject were subjected to an exercise protocol consisting of running on a treadmill (5.4–6.7 mile/h at 1° of incline) in a warm climate-controlled chamber after receiving 0, 2, or 4 mg of glycopyrrolate. Core temperature, heart rate, rater of perceived exertion, and sweat rate were monitored in both subjects. Results: Glycopyrrolate dose was not significantly correlated with decreased sweat rate and maximal core temperature. However, the clinical effect of reducing the sweat rate was very strong. The improvement of the subject’s sweat rate allowed him to successfully return to sport. Conclusion: Our findings suggest that low-dose glycopyrrolate may be a safe and effective method of controlling exertional hyperhidrosis.
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Affiliation(s)
- Matthew Negaard
- Department of Emergency Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Christopher Anthony
- Department of Orthopedic Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Daniel Bonthius
- College of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Matthew Jepson
- Department of Family Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Britt Marcussen
- Department of Family Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Daniel Pelzer
- Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Andrew Peterson
- Sports Medicine Clinic, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
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Judge LW, Kumley RF, Bellar DM, Pike KL, Pierson EE, Weidner T, Pearson D, Friesen CA. Hydration and Fluid Replacement Knowledge, Attitudes, Barriers, and Behaviors of NCAA Division 1 American Football Players. J Strength Cond Res 2016; 30:2972-2978. [PMID: 26950346 DOI: 10.1519/jsc.0000000000001397] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Judge, LW, Kumley, RF, Bellar, DM, Pike, KL, Pierson, EE, Weidner, T, Pearson, D, and Friesen, CA. Hydration and fluid replacement knowledge, attitudes, barriers, and behaviors of NCAA Division 1 American football players. J Strength Cond Res 30(11): 2972-2978, 2016-Hydration is an important part of athletic performance, and understanding athletes' hydration knowledge, attitudes, barriers, and behaviors is critical for sport practitioners. The aim of this study was to assess National Collegiate Athletic Association (NCAA) Division 1 (D1) American football players, with regard to hydration and fluid intake before, during, and after exercise, and to apply this assessment to their overall hydration practice. The sample consisted of 100 student-athletes from 2 different NCAA D1 universities, who participated in voluntary summer football conditioning. Participants completed a survey to identify the fluid and hydration knowledge, attitudes and behaviors, demographic data, primary football position, previous nutrition education, and barriers to adequate fluid consumption. The average Hydration Knowledge Score (HKS) for the participants in the present study was 11.8 ± 1.9 (69.4% correct), with scores ranging from 42 to 100% correct. Four key misunderstandings regarding hydration, specifically related to intervals of hydration habits among the study subjects, were revealed. Only 24% of the players reported drinking enough fluids before, during, immediately after, and 2 hours after practice. Generalized linear model analysis predicted the outcome variable HKS (χ = 28.001, p = 0.045), with nutrition education (Wald χ = 8.250, p = 0.041) and position on the football team (χ = 9.361, p = 0.025) being significant predictors. "Backs" (e.g., quarterbacks, running backs, and defensive backs) demonstrated significantly higher hydration knowledge than "Linemen" (p = 0.014). Findings indicated that if changes are not made to increase hydration awareness levels among football teams, serious health consequences, including potential fatalities, could occur on the field, especially among heavier linemen.
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Affiliation(s)
- Lawrence W Judge
- 1School of Kinesiology, Ball State University, Muncie, Indiana; 2Department of Family and Consumer Sciences, Ball State University, Muncie, Indiana; 3School of Kinesiology, University of Louisiana at Lafayette, Lafayette, Louisiana; and 4Didactic Program in Dietetics, Ball State University, Muncie, Indiana
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Koenders EE, Franken CPG, Cotter JD, Thornton SN, Rehrer NJ. Restricting dietary sodium reduces plasma sodium response to exercise in the heat. Scand J Med Sci Sports 2016; 27:1213-1220. [DOI: 10.1111/sms.12748] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2016] [Indexed: 01/25/2023]
Affiliation(s)
- E. E. Koenders
- Department of Physiology; Radboud University; Nijmegen The Netherlands
| | - C. P. G. Franken
- Department of Physiology; Radboud University; Nijmegen The Netherlands
| | - J. D. Cotter
- School of Physical Education Sport & Exercise Sciences; Otago University; Dunedin New Zealand
| | - S. N. Thornton
- Faculty of Sciences; University of Lorraine; INSERM UMR_S.1116; Nancy France
| | - N. J. Rehrer
- School of Physical Education Sport & Exercise Sciences; Otago University; Dunedin New Zealand
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Lara B, Gallo-Salazar C, Puente C, Areces F, Salinero JJ, Del Coso J. Interindividual variability in sweat electrolyte concentration in marathoners. J Int Soc Sports Nutr 2016; 13:31. [PMID: 27478425 PMCID: PMC4966593 DOI: 10.1186/s12970-016-0141-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/07/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Sodium (Na(+)) intake during exercise aims to replace the Na(+) lost by sweat to avoid electrolyte imbalances, especially in endurance disciplines. However, Na(+) needs can be very different among individuals because of the great inter-individual variability in sweat electrolyte concentration. The aim of this investigation was to determine sweat electrolyte concentration in a large group of marathoners. METHODS A total of 157 experienced runners (141 men and 16 women) completed a marathon race (24.4 ± 3.6 °C and 27.7 ± 4.8 % of humidity). During the race, sweat samples were collected by using sweat patches placed on the runners' forearms. Sweat electrolyte concentration was measured by using photoelectric flame photometry. RESULTS As a group, sweat Na(+) concentration was 42.9 ± 18.7 mmol·L(-1) (minimal-maximal value = 7.0-95.5 mmol·L(-1)), sweat Cl(-) concentration was 32.2 ± 15.6 mmol·L(-1) (7.3-90.6 mmol·L(-1)) and sweat K(+) concentration was 6.0 ± 0.9 mmol·L(-1) (3.1-8.0 mmol·L(-1)). Women presented lower sweat Na(+) (33.9 ± 12.1 vs 44.0 ± 19.1 mmol·L(-1); P = 0.04) and sweat Cl(-) concentrations (22.9 ± 10.5 vs 33.2 ± 15.8 mmol·L(-1); P = 0.01) than men. A 20 % of individuals presented a sweat Na(+) concentration higher than 60 mmol·L(-1) while this threshold was not surpassed by any female marathoner. Sweat electrolyte concentration did not correlate to sweat rate, age, body characteristics, experience or training. Although there was a significant correlation between sweat Na(+) concentration and running pace (r = 0.18; P = 0.03), this association was weak to interpret that sweat Na(+) concentration increased with running pace. CONCLUSIONS The inter-individual variability in sweat electrolyte concentration was not explained by any individual characteristics except for individual running pace and sex. An important portion (20 %) of marathoners might need special sodium intake recommendations due to their high sweat salt losses.
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Affiliation(s)
- Beatriz Lara
- Camilo José Cela University Exercise Physiology Laboratory, C/ Castillo de Alarcon, 49, Villafranca del Castillo, 28692 Spain
| | - César Gallo-Salazar
- Camilo José Cela University Exercise Physiology Laboratory, C/ Castillo de Alarcon, 49, Villafranca del Castillo, 28692 Spain
| | - Carlos Puente
- Camilo José Cela University Exercise Physiology Laboratory, C/ Castillo de Alarcon, 49, Villafranca del Castillo, 28692 Spain
| | - Francisco Areces
- Camilo José Cela University Exercise Physiology Laboratory, C/ Castillo de Alarcon, 49, Villafranca del Castillo, 28692 Spain
| | - Juan José Salinero
- Camilo José Cela University Exercise Physiology Laboratory, C/ Castillo de Alarcon, 49, Villafranca del Castillo, 28692 Spain
| | - Juan Del Coso
- Camilo José Cela University Exercise Physiology Laboratory, C/ Castillo de Alarcon, 49, Villafranca del Castillo, 28692 Spain
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Pokora I, Żebrowska A. Application of A Physiological Strain Index in Evaluating Responses to Exercise Stress - A Comparison Between Endurance and High Intensity Intermittent Trained Athletes. J Hum Kinet 2016; 50:103-114. [PMID: 28149347 PMCID: PMC5260640 DOI: 10.1515/hukin-2015-0142] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2016] [Indexed: 11/22/2022] Open
Abstract
The study evaluated differences in response to exercise stress between endurance and
high-intensity intermittent trained athletes in a thermoneutral environment using a
physiological strain index (PSI). Thirty-two subjects participated in a running
exercise under normal (23°C, 50% RH) conditions. The group included nine
endurance trained athletes (middle-distance runners - MD), twelve high-intensity
intermittent trained athletes (soccer players - HIIT) and eleven students who
constituted a control group. The exercise started at a speed of 4
km·h–1 which was increased every 3 min by 2
km·h–1 to volitional exhaustion. The heart rate was
recorded with a heart rate monitor and aural canal temperature was measured using an
aural canal temperature probe. The physiological strain index (PSI) and the
contribution of the circulatory and thermal components to the overall physiological
strain were calculated from the heart rate and aural canal temperature. The
physiological strain index differed between the study and control participants, but
not between the MD and HIIT groups. The physiological strain in response to exercise
stress in a thermoneutral environment was mainly determined based on the circulatory
strain (MD group - 73%, HIIT group – 70%). The contribution of the circulatory
and thermal components to the physiological strain did not differ significantly
between the trained groups (MD and HIIT) despite important differences in
morphological characteristics and training-induced systemic cardiovascular and
thermoregulatory adaptations.
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Affiliation(s)
- Ilona Pokora
- Department of Physiology, the Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Aleksandra Żebrowska
- Department of Physiology, the Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
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Davis JK, Baker LB, Barnes K, Ungaro C, Stofan J. Thermoregulation, Fluid Balance, and Sweat Losses in American Football Players. Sports Med 2016; 46:1391-405. [DOI: 10.1007/s40279-016-0527-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hew-Butler T, Rosner MH, Fowkes-Godek S, Dugas JP, Hoffman MD, Lewis DP, Maughan RJ, Miller KC, Montain SJ, Rehrer NJ, Roberts WO, Rogers IR, Siegel AJ, Stuempfle KJ, Winger JM, Verbalis JG. Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clin J Sport Med 2015; 25:303-20. [PMID: 26102445 DOI: 10.1097/jsm.0000000000000221] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Tamara Hew-Butler
- *Exercise Science Program, Oakland University, Rochester, Michigan; †Division of Nephrology, University of Virginia Health System, Charlottesville, Virginia; ‡Department of Sports Medicine, West Chester University, West Chester, Pennsylvania; §The Vitality Group, Chicago, Illinois; ¶Department of Physical Medicine and Rehabilitation, VA Northern California Health Care System and University of California Davis, Sacramento, California; ‖Family Medicine Residency Program, Via Christi Hospitals Wichita, Inc, Wichita, Kansas; **Department of Sport and Exercise Nutrition, Loughborough University, Leicestershire, United Kingdom; ††Athletic Training Program, Central Michigan University, Mount Pleasant, Michigan; ‡‡Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts; §§School of Physical Education, Sport and Exercise Science, University of Otago, Dunedin, New Zealand; ¶¶Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota; ‖‖Department of Emergency Medicine, St John of God Murdoch Hospital and University of Notre Dame, Perth, Western Australia; ***Department of Internal Medicine, Harvard Medical School, Boston, Massachusetts; †††Health Sciences Department, Gettysburg College, Gettysburg, Pennsylvania; ‡‡‡Department of Family Medicine, Loyola University Chicago Stritch School of Medicine, Chicago, Illinois; and §§§Department of Endocrinology and Metabolism, Georgetown University Medical Center, Washington, District of Columbia
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Jackson K, Rubin R, Van Hoeck N, Hauert T, Lana V, Wang H. The effect of selective head-neck cooling on physiological and cognitive functions in healthy volunteers. Transl Neurosci 2015; 6:131-138. [PMID: 28123796 PMCID: PMC4936650 DOI: 10.1515/tnsci-2015-0012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/07/2015] [Indexed: 11/15/2022] Open
Abstract
In general, brain temperatures are elevated during physical sporting activities; therefore, reducing brain temperature shortly after a sports-related concussion (SRC) could be a promising intervention technique. The main objective of this study was to examine the effects of head and neck cooling on physiological and cognitive function in normal healthy volunteers. Twelve healthy volunteers underwent two different sessions of combined head and neck cooling, one session with a cold pack and one session with a room temperature pack. Physiological measurements included: systolic/diastolic blood pressure, pulse oximetry, heart rate, and sublingual and tympanic temperature. Cognitive assessment included: processing speed, executive function, and working memory tasks. Physiological measurements were taken pre-, mid- and post-cooling, while cognitive assessments were done before and after cooling. The order of the sessions was randomized. There was a significant decrease in tympanic temperature across both sessions; however more cooling occurred when the cold pack was in the device. There was no significant decrease in sublingual temperature across either session. The observed heart rates, pulse oximetry, systolic and diastolic blood pressure during the sessions were all within range of a normal healthy adult. Cognitive assessment remained stable across each session for both pre- and post-cooling. We propose that optimizing brain temperature management after brain injury using head and neck cooling technology may represent a sensible, practical, and effective strategy to potentially enhance recovery and perhaps minimize the subsequent short and long term consequences from SRC.
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Affiliation(s)
- Kevin Jackson
- Thermal Neuroscience Beckman Institute University of Illinois Urbana, IL 61801, USA
| | - Rachael Rubin
- Thermal Neuroscience Beckman Institute University of Illinois Urbana, IL 61801, USA; Carle Foundation Hospital Urbana, Il 61801, USA
| | - Nicole Van Hoeck
- Psychological & Educational Sciences Vrije Universiteit Brussel, Belgium
| | - Tommy Hauert
- Thermal Neuroscience Beckman Institute University of Illinois Urbana, IL 61801, USA
| | - Valentina Lana
- Thermal Neuroscience Beckman Institute University of Illinois Urbana, IL 61801, USA
| | - Huan Wang
- Thermal Neuroscience Beckman Institute University of Illinois Urbana, IL 61801, USA; Carle Foundation Hospital Urbana, Il 61801, USA
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Wang H, Wang B, Jackson K, Miller CM, Hasadsri L, Llano D, Rubin R, Zimmerman J, Johnson C, Sutton B. A novel head-neck cooling device for concussion injury in contact sports. Transl Neurosci 2015; 6:20-31. [PMID: 28123788 PMCID: PMC4936612 DOI: 10.1515/tnsci-2015-0004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 11/29/2014] [Indexed: 12/21/2022] Open
Abstract
Emerging research on the long-term impact of concussions on athletes has allowed public recognition of the potentially devastating effects of these and other mild head injuries. Mild traumatic brain injury (mTBI) is a multifaceted disease for which management remains a clinical challenge. Recent pre-clinical and clinical data strongly suggest a destructive synergism between brain temperature elevation and mTBI; conversely, brain hypothermia, with its broader, pleiotropic effects, represents the most potent neuro-protectant in laboratory studies to date. Although well-established in selected clinical conditions, a systemic approach to accomplish regional hypothermia has failed to yield an effective treatment strategy in traumatic brain injury (TBI). Furthermore, although systemic hypothermia remains a potentially valid treatment strategy for moderate to severe TBIs, it is neither practical nor safe for mTBIs. Therefore, selective head-neck cooling may represent an ideal strategy to provide therapeutic benefits to the brain. Optimizing brain temperature management using a National Aeronautics and Space Administration (NASA) spacesuit spinoff head-neck cooling technology before and/or after mTBI in contact sports may represent a sensible, practical, and effective method to potentially enhance recover and minimize post-injury deficits. In this paper, we discuss and summarize the anatomical, physiological, preclinical, and clinical data concerning NASA spinoff head-neck cooling technology as a potential treatment for mTBIs, particularly in the context of contact sports.
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Affiliation(s)
- Huan Wang
- Department of Neurosurgery, Carle Foundation Hospital, University of Illinois College of Medicine at Urbana-Champaign, Urbana, USA; Thermal Neuroscience Laboratory, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Bonnie Wang
- Department of Internal Medicine, Carle Foundation Hospital, University of Illinois College of Medicine at Urbana-Champaign, Urbana, USA
| | - Kevin Jackson
- Thermal Neuroscience Laboratory, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Claire M Miller
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Linda Hasadsri
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Daniel Llano
- Department of Molecular and Integrative Physiology, University of Illinois College of Medicine at Urbana-Champaign, Carle Foundation Hospital, Urbana, USA; The Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Rachael Rubin
- The Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Jarred Zimmerman
- Department of Sports Medicine, Carle Foundation Hospital, Urbana, USA
| | - Curtis Johnson
- The Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA; Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Brad Sutton
- The Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, USA; Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, USA
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Savoie FA, Dion T, Asselin A, Gariepy C, Boucher PM, Berrigan F, Goulet EDB. Intestinal temperature does not reflect rectal temperature during prolonged, intense running with cold fluid ingestion. Physiol Meas 2015; 36:259-72. [DOI: 10.1088/0967-3334/36/2/259] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Abstract
The objective of this article is to provide a review of the fundamental aspects of body fluid balance and the physiological consequences of water imbalances, as well as discuss considerations for the optimal composition of a fluid replacement beverage across a broad range of applications. Early pioneering research involving fluid replacement in persons suffering from diarrheal disease and in military, occupational, and athlete populations incurring exercise- and/or heat-induced sweat losses has provided much of the insight regarding basic principles on beverage palatability, voluntary fluid intake, fluid absorption, and fluid retention. We review this work and also discuss more recent advances in the understanding of fluid replacement as it applies to various populations (military, athletes, occupational, men, women, children, and older adults) and situations (pathophysiological factors, spaceflight, bed rest, long plane flights, heat stress, altitude/cold exposure, and recreational exercise). We discuss how beverage carbohydrate and electrolytes impact fluid replacement. We also discuss nutrients and compounds that are often included in fluid-replacement beverages to augment physiological functions unrelated to hydration, such as the provision of energy. The optimal composition of a fluid-replacement beverage depends upon the source of the fluid loss, whether from sweat, urine, respiration, or diarrhea/vomiting. It is also apparent that the optimal fluid-replacement beverage is one that is customized according to specific physiological needs, environmental conditions, desired benefits, and individual characteristics and taste preferences.
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Yeargin SW, Finn ME, Eberman LE, Gage MJ, McDermott BP, Niemann A. Ad libitum fluid consumption via self- or external administration. J Athl Train 2014; 50:51-8. [PMID: 25389698 DOI: 10.4085/1062-6050-49.3.76] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT During team athletic events, athletic trainers commonly provide fluids with water bottles. When a limited number of water bottles exist, various techniques are used to deliver fluids. OBJECTIVE To determine whether fluid delivered via water-bottle administration influenced fluid consumption and hydration status. DESIGN Crossover study. SETTING Outdoor field (22.2°C ± 3.5°C). PATIENTS OR OTHER PARTICIPANTS Nineteen participants (14 men, 5 women, age = 30 ± 10 years, height = 176 ± 8 cm, mass = 72.5 ± 10 kg) were recruited from the university and local running clubs. INTERVENTION(S) The independent variable was fluid delivery with 3 levels: self-administration with mouth-to-bottle direct contact (SA-DC), self-administration with no contact between mouth and bottle (SA-NC), and external administration with no contact between the mouth and the bottle (EA-NC). Participants warmed up for 10 minutes before completing 5 exercise stations, after which an ad libitum fluid break was given, for a total of 6 breaks. MAIN OUTCOME MEASURE(S) We measured the fluid variables of total volume consumed, total number of squirts, and average volume per squirt. Hydration status via urine osmolality and body-mass loss, and perceptual variables for thirst and fullness were recorded. We calculated repeated-measures analyses of variance to assess hydration status, fluid variables, and perceptual measures to analyze conditions across time. RESULTS The total volume consumed for EA-NC was lower than for SA-DC (P = .001) and SA-NC (P = .001). The total number of squirts for SA-DC was lower than for SA-NC (P = .009). The average volume per squirt for EA-NC was lower than for SA-DC (P = .020) and SA-NC (P = .009). Participants arrived (601.0 ± 21.3 mOsm/L) and remained (622.3 ± 38.3 mOsm/L) hydrated, with no difference between conditions (P = .544); however, the EA-NC condition lost more body mass than did the SA-DC condition (P = .001). There was no main effect for condition on thirst (P = .147) or fullness (P = .475). CONCLUSIONS External administration of fluid decreased total volume consumed via a decreased average volume per squirt. The SA-DC method requires fewer squirts within a specific time frame. Fluid breaks every 15 minutes resulted in maintenance of euhydration; however, loss of body mass was influenced by fluid administration. Athletic trainers should avoid external administration to promote positive hydration behaviors. When fluid is self-administered, individual bottles may be the best clinical practice because more volume can be consumed per squirt.
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Affiliation(s)
- Susan W Yeargin
- Department of Physical Education and Athletic Training, University of South Carolina, Columbia
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Cotter JD, Thornton SN, Lee JK, Laursen PB. Are we being drowned in hydration advice? Thirsty for more? EXTREME PHYSIOLOGY & MEDICINE 2014; 3:18. [PMID: 25356197 PMCID: PMC4212586 DOI: 10.1186/2046-7648-3-18] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/01/2014] [Indexed: 12/29/2022]
Abstract
Hydration pertains simplistically to body water volume. Functionally, however, hydration is one aspect of fluid regulation that is far more complex, as it involves the homeostatic regulation of total body fluid volume, composition and distribution. Deliberate or pathological alteration of these regulated factors can be disabling or fatal, whereas they are impacted by exercise and by all environmental stressors (e.g. heat, immersion, gravity) both acutely and chronically. For example, dehydration during exercising and environmental heat stress reduces water volume more than electrolyte content, causing hyperosmotic hypohydration. If exercise continues for many hours with access to food and water, composition returns to normal but extracellular volume increases well above baseline (if exercising upright and at low altitude). Repeating bouts of exercise or heat stress does likewise. Dehydration due to physical activity or environmental heat is a routine fluid-regulatory stress. How to gauge such dehydration and - more importantly-what to do about it, are contested heavily within sports medicine and nutrition. Drinking to limit changes in body mass is commonly advocated (to maintain ≤2% reduction), rather than relying on behavioural cues (mainly thirst) because the latter has been deemed too insensitive. This review, as part of the series on moving in extreme environments, critiques the validity, problems and merits of externally versus autonomously controlled fluid-regulatory behaviours, both acutely and chronically. Our contention is that externally advocated hydration policies (especially based on change in body mass with exercise in healthy individuals) have limited merit and are extrapolated and imposed too widely upon society, at the expense of autonomy. More research is warranted to examine whether ad libitum versus avid drinking is beneficial, detrimental or neither in: acute settings; adapting for obligatory dehydration (e.g. elite endurance competition in the heat), and; development of chronic diseases that are associated with an extreme lack of environmental stress.
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Affiliation(s)
- James David Cotter
- Exercise and Environmental Physiology, School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Simon N Thornton
- Faculté de Médecine, Université de Lorraine, U 1116 -INSERM-UL, 9, Avenue de la forêt de Haye, CS50-184 - 54505 VANDŒUVRE, Les Nancy cedex, France
| | - Jason Kw Lee
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore ; Yong Loo Lin School of Medicine, National University of Singapore, Singapore ; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Paul B Laursen
- High Performance Sport New Zealand, Auckland, New Zealand ; Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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Cosgrove SD, Love TD, Brown RC, Baker DF, Howe AS, Black KE. Fluid and Electrolyte Balance During Two Different Preseason Training Sessions in Elite Rugby Union Players. J Strength Cond Res 2014; 28:520-7. [DOI: 10.1519/jsc.0b013e3182986d43] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Pryor RR, Casa DJ, Adams WM, Belval LN, DeMartini JK, Huggins RA, Stearns RL, Vandermark LW. Maximizing Athletic Performance in the Heat. Strength Cond J 2013. [DOI: 10.1519/ssc.0000000000000016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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McDermott BP, Casa DJ, Lee E, Yamamoto L, Beasley K, Emmanuel H, Anderson J, Pescatello L, Armstrong LE, Maresh C. Thermoregulation and stress hormone recovery after exercise dehydration: comparison of rehydration methods. J Athl Train 2013; 48:725-33. [PMID: 24143900 DOI: 10.4085/1062-6050-48.6.01] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Athletic trainers recommend and use a multitude of rehydration (REHY) methods with their patients. The REHY modality that most effectively facilitates recovery is unknown. OBJECTIVE To compare 5 common REHY methods for thermoregulatory and stress hormone recovery after exercise dehydration (EXDE) in trained participants. DESIGN Randomized, cross-over, controlled study. PATIENTS OR OTHER PARTICIPANTS Twelve physically active, non-heat-acclimatized men (age = 23 ± 4 years, height = 180 ± 6 cm, mass = 81.3 ± 3.7 kg, VO2max = 56.9 ± 4.4 mL·min(-1)·kg(-1), body fat = 7.9% ± 3%) participated. INTERVENTION(S) Participants completed 20-hour fluid restriction and 2-hour EXDE; they then received no fluid (NF) or REHY (half-normal saline) via ad libitum (AL), oral (OR), intravenous (IV), or combination IV and OR (IV + OR) routes for 30 minutes; and then were observed for another 30 minutes. MAIN OUTCOME MEASURE(S) Body mass, rectal temperature, 4-site mean weighted skin temperature, plasma stress hormone concentrations, and environmental symptoms questionnaire (ESQ) score. RESULTS Participants were hypohydrated (body mass -4.23% ± 0.22%) post-EXDE. Rectal temperature for the NF group was significantly greater than for the IV group (P = .023) at 30 minutes after beginning REHY (REHY30) and greater than OR, IV, and IV + OR (P ≤ .009) but not AL (P = .068) at REHY60. Mean weighted skin temperature during AL was less than during IV + OR at REHY5 (P = .019). The AL participants demonstrated increased plasma cortisol concentrations compared with IV + OR, independent of time (P = .015). No differences existed between catecholamine concentrations across treatments (P > .05). The ESQ score was increased at REHY60 for NF, AL, OR, and IV (P < .05) but not for IV + OR (P = .217). The NF ESQ score was greater than that of IV + OR at REHY60 (P = .012). CONCLUSIONS Combination IV + OR REHY reduced body temperature to a greater degree than OR and AL REHY when compared with NF. Future studies addressing clinical implications are needed.
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Affiliation(s)
- Brendon P McDermott
- Athletic Training Education Program, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville
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Cosgrove SD, Black KE. Sodium supplementation has no effect on endurance performance during a cycling time-trial in cool conditions: a randomised cross-over trial. J Int Soc Sports Nutr 2013; 10:30. [PMID: 23731903 PMCID: PMC3680189 DOI: 10.1186/1550-2783-10-30] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/27/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sodium ingestion during exercise may exert beneficial effects on endurance performance by either its ability to attenuate the decrease in plasma volume or reduce the risk of Exercise Associated Hyponatremia (EAH). This study aimed to investigate the effect of sodium supplements on endurance performance during a 72 km road cycling time-trial in cool conditions (13.8 ± 2.0°C). METHODS Nine well-trained cyclists (5 male, 4 female) participated in this randomized, double-blinded cross-over study, receiving either a 700 mg(.)h(-1) salt capsule, or a corn flour placebo during the time trial. Water was ingested ad-libitum throughout the time trial. Measurements were taken pre, post, and 40 min following time-trials, analysing blood, sweat, and urinary hydration and sodium concentration. RESULTS Sodium supplements had no effect on time-trial performance (overall time = 171 min sodium vs. 172 min placebo; p = 0.46). There was also no effect on the change in plasma sodium concentration from pre to post time trial between trials (relative plasma [Na(+)] change (pre-post): sodium = 0.56%, placebo = 0.47%; p = 0.60). The greatest difference observed was a significantly change in plasma volume from pre to post exercise between the salt and the placebo trial (p = 0.02), which corresponded with an increased thirst with sodium supplementation. CONCLUSION Sodium supplements therefore do not improving performance during exercise of approximately 3 h duration in cool conditions.
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Affiliation(s)
- Samuel David Cosgrove
- Department of Human Nutrition, University of Otago, P.O. Box 56, Dunedin, Otago 9054, New Zealand
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Long D, Perry C, Unruh SA, Lewis N, Stanek-Krogstrand K. Personal food systems of male collegiate football players: a grounded theory investigation. J Athl Train 2012; 46:688-95. [PMID: 22488196 DOI: 10.4085/1062-6050-46.6.688] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Factors that affect food choices include the physical and social environments, quality, quantity, perceived healthfulness, and convenience. The personal food choice process was defined as the procedures used by athletes for making food choices, including the weighing and balancing of activities of daily life, physical well-being, convenience, monetary resources, and social relationships. OBJECTIVE To develop a theoretical model explaining the personal food choice processes of collegiate football players. DESIGN Qualitative study. SETTING National Collegiate Athletic Association Division II football program. PATIENTS OR OTHER PARTICIPANTS Fifteen football players were purposefully sampled to represent various positions, years of athletic eligibility, and ethnic backgrounds. DATA COLLECTION AND ANALYSIS For text data collection, we used predetermined, open-ended questions. Data were analyzed using the constant comparison method. The athletes' words were used to label and describe their interactions and experiences with the food choice process. Member checks and an external audit were conducted by a qualitative methodologist and a nutrition specialist, and the findings were triangulated with the current literature to ensure trustworthiness of the text data. RESULTS Time was the core category and yielded a cyclic graphic of a theoretical model for the food choice system. Planning hydration, macronutrient strategies, snacks, and healthful food choices emerged as themes. CONCLUSIONS The athletes planned meals and snacks around their academic and athletic schedules while attempting to consume foods identified as healthful. Healthful foods were generally lower in fat but high in preferred macronutrients. High-protein foods were the players' primary goal; carbohydrate consumption was secondary. The athletes had established plans to maintain hydration. Professionals may use these findings to implement educational programs on food choices for football players.
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Affiliation(s)
- Doug Long
- University of Nebraska, Lincoln, NE, USA.
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Comparison between blood and urinary fluid balance indices during dehydrating exercise and the subsequent hypohydration when fluid is not restored. Eur J Appl Physiol 2012; 113:611-20. [PMID: 22886188 DOI: 10.1007/s00421-012-2467-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Accepted: 07/23/2012] [Indexed: 10/27/2022]
Abstract
Blood serum osmolality (S (OSM)) is the gold standard to assess body fluid balance. Urine specific gravity (U (SG)) is also a body fluid balance index but it is not invasive. However, U (SG) capability to detect the minimal level of dehydration that affects athletic performance (i.e., 2 %) remains untested. We collected urine and blood samples in eighteen euhydrated trained athletes in the morning and that evening while dehydrating by 1, 2, and 3 % of body mass by cycling (60 % VO₂peak) in the heat (32 °C, 46 % rh, 2.5 m s(-1) air flow). At 9:00 pm, subjects left the laboratory and went to bed after ingesting 0.7 ± 0.2 L of a sports drink. The next morning, subjects awoke 3 % hypohydrated, and blood and urine samples were collected and test terminated. We found that 2 % dehydration increased S (OSM) and U (SG) above exercise-baseline values (P < 0.05). The next morning, S (OSM) and U (SG) remained elevated compared to the first morning while euhydrated (287 ± 5 vs. 282 ± 3 mOsmol kg(-1) H(2)O and 1.028 ± 0.003 vs. 1.017 ± 0.005, respectively, P < 0.05). However, when comparing 3 % dehydration (end of exercise) to 3 % hypohydration (next morning), U (SG) increased (1.025 ± 0.003 to 1.028 ± 0.003; P < 0.05) while S (OSM) decreased (295 ± 5 to 287 ± 5 mOsmol kg(-1) H(2)O; P < 0.05). In summary, during exercise-induced dehydration, U (SG) is as sensitive as S (OSM) to detect low levels of dehydration (i.e., 2 %). Both indices maintain the ability to detect a 3 % overnight hypohydration although S (OSM) approaches euhydration values, while U (SG) remains a superior index to detect hypohydration.
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DEREN TOMASZM, CORIS ERICE, BAIN ANTHONYR, WALZ STEVEM, JAY OLLIE. Sweating Is Greater in NCAA Football Linemen Independently of Heat Production. Med Sci Sports Exerc 2012; 44:244-52. [DOI: 10.1249/mss.0b013e31822cb4e2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sawka MN, Leon LR, Montain SJ, Sonna LA. Integrated Physiological Mechanisms of Exercise Performance, Adaptation, and Maladaptation to Heat Stress. Compr Physiol 2011; 1:1883-928. [DOI: 10.1002/cphy.c100082] [Citation(s) in RCA: 299] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Ferguson DP, Bowen RS, Lightfoot JT. Heart Rate and Core Temperature Responses of Elite Pit Crews during Automobile Races. J Strength Cond Res 2011; 25:2075-83. [DOI: 10.1519/jsc.0b013e3181f5676d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Unwin RJ, Luft FC, Shirley DG. Pathophysiology and management of hypokalemia: a clinical perspective. Nat Rev Nephrol 2011; 7:75-84. [PMID: 21278718 DOI: 10.1038/nrneph.2010.175] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Potassium (K(+)) ions are the predominant intracellular cations. K(+) homeostasis depends on external balance (dietary intake [typically 100 mmol per day] versus excretion [95% via the kidney; 5% via the colon]) and internal balance (the distribution of K(+) between intracellular and extracellular fluid compartments). The uneven distribution of K(+) across cell membranes means that a mere 1% shift in its distribution can cause a 50% change in plasma K(+) concentration. Hormonal mechanisms (involving insulin, β-adrenergic agonists and aldosterone) modulate K(+) distribution by promoting rapid transfer of K(+) across the plasma membrane. Extrarenal K(+) losses from the body are usually small, but can be marked in individuals with chronic diarrhea, severe burns or prolonged sweating. Under normal circumstances, the kidney's distal nephron secretes K(+) and determines final urinary excretion. In patients with hypokalemia (plasma K(+) concentration <3.5 mmol/l), after the exclusion of extrarenal causes, alterations in sodium ion delivery to the distal nephron, mineralocorticoid status, or a specific inherited or acquired defect in distal nephron function (each of which affects distal nephron K(+) secretion), should be considered. Clinical management of hypokalemia should establish the underlying cause and alleviate the primary disorder. This Review aims to inform clinicians about the pathophysiology and appropriate treatment for hypokalemia.
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Affiliation(s)
- Robert J Unwin
- Centre for Nephrology, Royal Free Hospital, University College London, Rowland Hill Street, London NW3 2PF, UK.
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Silva RP, Mündel T, Natali AJ, Bara Filho MG, Lima JRP, Alfenas RCG, Lopes PRNR, Belfort FG, Marins JCB. Fluid balance of elite Brazilian youth soccer players during consecutive days of training. J Sports Sci 2011; 29:725-32. [DOI: 10.1080/02640414.2011.552189] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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