1
|
Goods PSR, Wall B, Galna B, McKay AKA, Jennings D, Peeling P, Watson G. Sweat Characteristics and Fluid Balance Responses During Two Heat Training Camps in Elite Female Field Hockey Players. Int J Sport Nutr Exerc Metab 2024; 34:79-87. [PMID: 38215732 DOI: 10.1123/ijsnem.2023-0159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/02/2023] [Accepted: 11/16/2023] [Indexed: 01/14/2024]
Abstract
We examined the sweat characteristics and fluid balance of elite female field hockey players during two heat training camps. Fourteen elite female field hockey players from the Australian national squad participated in two heat training camps held ∼6 months apart, following winter- (Camp 1) and summer-based training (Camp 2). Daily waking body mass (BM) and urine specific gravity (USG) were collected, along with several markers of sweat and fluid balance across two matches per camp. There was a 19% mean reduction in estimated whole-body sweat sodium concentration from Camp 1 (45.8 ± 6.5 mmol/L) to Camp 2 (37.0 ± 5.0 mmol/L; p < .001). Waking urine specific gravity ≥ 1.020 was observed in 31% of samples, with no significant differences in mean urine specific gravity or BM between camps (p > .05), but with substantial interindividual variation. Intramatch sweat rates were high (1.2-1.8 L/hr), with greater BM losses in Camp 1 (p = .030), resulting in fewer players losing ≥2% BM in Camp 2 (0%-8%), as compared with Camp 1 (36%-43%; p = .017). Our field data suggest that elite female field hockey players experience substantial sweat losses during competition in the heat regardless of the season. In agreement with previous findings, we observed substantial interindividual variation in sweat and hydration indices, supporting the use of individualized athlete hydration strategies.
Collapse
Affiliation(s)
- Paul S R Goods
- School of Allied Health (Exercise Science), Murdoch University, Murdoch, WA, Australia
- Center for Healthy Aging, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Western Australian Institute of Sport, Mt Claremont, WA, Australia
| | - Bradley Wall
- School of Allied Health (Exercise Science), Murdoch University, Murdoch, WA, Australia
- Center for Healthy Aging, Health Futures Institute, Murdoch University, Perth, WA, Australia
| | - Brook Galna
- School of Allied Health (Exercise Science), Murdoch University, Murdoch, WA, Australia
- Center for Healthy Aging, Health Futures Institute, Murdoch University, Perth, WA, Australia
| | - Alannah K A McKay
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
| | - Denise Jennings
- High Performance Program, Hockey Australia, Perth, WA, Australia
| | - Peter Peeling
- Western Australian Institute of Sport, Mt Claremont, WA, Australia
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Crawley, WA, Australia
| | - Greig Watson
- School of Allied Health (Exercise Science), Murdoch University, Murdoch, WA, Australia
- Center for Healthy Aging, Health Futures Institute, Murdoch University, Perth, WA, Australia
| |
Collapse
|
2
|
Palejwala Z, Wallman KE, Maloney S, Landers GJ, Ecker UKH, Fear MW, Wood FM. Higher operating theatre temperature during burn surgery increases physiological heat strain, subjective workload, and fatigue of surgical staff. PLoS One 2023; 18:e0286746. [PMID: 37267345 DOI: 10.1371/journal.pone.0286746] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/22/2023] [Indexed: 06/04/2023] Open
Abstract
Raising the ambient temperature of the operating theatre is common practice during burn surgeries to maintain the patient's core body temperature; however, the effects of operating in the heat on cognitive performance, manual dexterity, and perceived workload of surgical staff have not been assessed in a real-world context. Therefore, the aim was to assess the real-time impact of heat during burn surgeries on staff's cognitive function, manual dexterity, and perceptual measures (workload, thermal sensation, thermal comfort, perceived exertion, and fatigue) and physiological parameters (core temperature, heart-rate, fluid loss, and dehydration). Ten burn surgery staff members were assessed in CON (24.0±1.1°C, 45±6% relative humidity [RH]) and HOT (30.8±1.6°C, 39±7% RH) burn surgeries (average 150 min duration). Cognitive performance, manual dexterity, and perceptual measures were recorded pre- and post-surgery, while physiological parameters were recorded throughout surgery. HOT conditions did not significantly affect manual dexterity or cognitive function (p > .05), however HOT resulted in heat strain (increased heart-rate, core temperature, and fluid loss: p < .05), and increased subjective workload, discomfort, perceived exertion, and fatigue compared to CON conditions (p < .05). Cognitive function and manual dexterity were maintained in hot conditions, suggesting that operating in approximately 31°C heat is a safe approach for patient treatment. However, job burnout, which is positively correlated with perceived workload, and the impact of cumulative fatigue on the mental health of surgery staff, must be considered in the context of supporting an effective health workforce.
Collapse
Affiliation(s)
- Zehra Palejwala
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Karen E Wallman
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Shane Maloney
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Grant J Landers
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Ullrich K H Ecker
- School of Psychological Science, The University of Western Australia, Crawley, Western Australia, Australia
| | - Mark W Fear
- School of Biomedical Sciences, University of Western Australia, Crawley, Western Australia, Australia
| | - Fiona M Wood
- Burn Injury Research Unit, Burn Service of WA South Metropolitan Health Service, University of Western Australia, Crawley, Western Australia, Australia
| |
Collapse
|
3
|
Donnan KJ, Williams EL, Bargh MJ. The effectiveness of heat preparation and alleviation strategies for cognitive performance: A systematic review. Temperature (Austin) 2023; 10:404-433. [PMID: 38130656 PMCID: PMC10732620 DOI: 10.1080/23328940.2022.2157645] [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: 08/24/2022] [Accepted: 12/01/2022] [Indexed: 12/15/2022] Open
Abstract
A range of occupational and performance contexts (e.g. military personnel operations, emergency services, sport) require the critical maintenance of cognitive performance in environmentally challenging environments. Several reviews exist which evaluate the effectiveness of heat preparation strategies to facilitate physical performance. To date, no review has explored the usefulness of heat preparation strategies for cognitive performance. Therefore, this systematic review aimed to evaluate a range of interventions for the maintenance of cognitive performance, during or following active or passive heat exposure. Studies to be included were assessed by two authors reviewing title, abstract, and full-text. Forty articles were identified which met the inclusion criteria. Interventions were categorised into chronic (i.e. acclimation/acclimatisation) and acute strategies (i.e. hydration, cooling, supplementation, psychological). The results indicate that medium-term consecutive heat acclimation may mitigate some cognitive deficits under heat stress, although heat acclimation effectiveness could be influenced by age. Further, pre-cooling appears the most effective cooling method for maintaining cognitive performance under heat stress, although results were somewhat ambiguous. The hydration literature showed that the most effective hydration strategies were those which individualised electrolyte fortified fluid volumes to match for sweat loss. Limited research exploring psychological interventions indicates that motivational self-talk could be facilitative for maintaining cognitive skills following exercise in hot conditions. These findings can be used to help inform strategies for maintaining critical cognitive and decision-making skills in hot environments.
Collapse
Affiliation(s)
- Kate J. Donnan
- Department of Sport, Exercise, and Rehabilitation Sciences, University of Hull, Hull, HU6 7RX, UK
| | - Emily L. Williams
- Centre for Human Performance, Carnegie School of Sport, Leeds Beckett University, Leeds, LS6 3QS, UK
| | - Melissa J. Bargh
- School of Sport and Exercise Science, College of Social Science of University of Lincoln, Lincoln, LN6 7TS, UK
| |
Collapse
|
4
|
Donnan KJ, Williams EL, Stanger N. The effect of exercise-induced fatigue and heat exposure on soccer-specific decision-making during high-intensity intermittent exercise. PLoS One 2022; 17:e0279109. [PMID: 36520792 PMCID: PMC9754236 DOI: 10.1371/journal.pone.0279109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022] Open
Abstract
Global warming and the globalisation of sport has increased the prevalence of sports competitions being held in hot environments. However, there is currently limited research investigating the impact of the heat on soccer-specific decision-making skills during exercise reflective of the physical demands of match-play. Therefore, the effects of heat exposure on physical and soccer-specific decision-making performance, biological markers (i.e., metanephrines), appraisal (i.e., challenge vs. threat) and affective states, during prolonged high-intensity intermittent exercise were investigated. Nine well-trained male soccer players completed a 92-min cycling intermittent sprint protocol (CISP), whilst simultaneously responding to a series of soccer-specific decision-making trials at various time points, in two temperature conditions: hot (32°C, 50%rh) and temperate (18°C, 50%rh). Results showed that decision-making score (p = .030) was impaired in the hot compared to the temperate condition. There was a reduced workload in the second half during the hot condition (p = .016), which coincided with a heightened threat state (p = .007) and more unpleasant feelings (p = .008) experienced in the hot, compared to temperate, condition. Furthermore, plasma normetanephrine (NMET) was higher at half-time (p = .012) and post-CISP (p ≤ .001). Also, plasma metanephrine (MET) was higher post-CISP (p = .009) in the hot compared to temperate condition, reflecting a heightened stress response. Our findings highlight the need for practitioners to consider the detrimental effects heat exposure can have on both physical and decision-making performance when looking to facilitate performance in hot conditions.
Collapse
Affiliation(s)
- Kate J. Donnan
- Department of Sport, Health and Exercise Science, University of Hull, Hull, United Kingdom
- * E-mail:
| | - Emily L. Williams
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Nicholas Stanger
- Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| |
Collapse
|
5
|
Excerpt. Physiol Behav 2022; 252:113852. [PMID: 35605843 DOI: 10.1016/j.physbeh.2022.113852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
6
|
Goodman SPJ, Immink MA, Marino FE. Hypohydration alters pre-frontal cortex haemodynamics, but does not impair motor learning. Exp Brain Res 2022; 240:2255-2268. [PMID: 35881154 PMCID: PMC9458583 DOI: 10.1007/s00221-022-06424-5] [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: 02/01/2022] [Accepted: 07/12/2022] [Indexed: 11/28/2022]
Abstract
It is unknown how hypohydration influences fine motor performance training and motor learning. Here, 30 participants (aged 19–46 years) were randomly assigned to a hypohydration (HYPO) or control (CON) group (both n = 15). Moderate hypohydration (~ 2.4% loss in body mass) was produced in HYPO via active dehydration before a 46 min fluid restricted rest period was undertaken. The conclusion of rest coincided with when CON attended the facilities. Both groups undertook a discrete sequence production task consisting of 6 training blocks, and returned ~ 300 min later to complete a delayed retention and transfer test while euhydrated. Bilateral pre-frontal cortex (PFC) haemodynamics were assessed using functional near-infrared spectroscopy throughout training and delayed learning assessments. Response time improved across training (P < 0.01) and was similar between the groups (both P = 0.22). Analysis of training PFC haemodynamics revealed a significant group by block interaction for oxygenated (O2Hb; P < 0.01), but not deoxygenated haemoglobin (P = 0.77). In training block 1, bilateral O2Hb was higher in HYPO (P = 0.02), while bilateral O2Hb increased in CON between blocks 2–3 and 5–6 (both P ≤ 0.03). During the delayed retention and transfer test, no group differences or interactions were found in response time, response error, or PFC haemodynamics (all P ≥ 0.27). Moderate hypohydration does increase PFC activation during motor skill learning, however, this appears to be transient and of little consequence to training or delayed retention or transfer performance.
Collapse
Affiliation(s)
- Stephen P J Goodman
- School of Allied Health, Exercise and Sport Science, Charles Sturt University, Bathurst, NSW, Australia. .,School of Science and Technology, University of New England, Armidale, NSW, Australia.
| | - Maarten A Immink
- Sport, Health, Physical Activity and Exercise Research Centre and College of Nursing and Health Sciences, Flinders University, Adelaide, SA, Australia
| | - Frank E Marino
- School of Allied Health, Exercise and Sport Science, Charles Sturt University, Bathurst, NSW, Australia
| |
Collapse
|
7
|
Yeoman K, Weakley A, DuBose W, Honn K, McMurry T, Eiter B, Baker B, Poplin G. Effects of heat strain on cognitive function among a sample of miners. APPLIED ERGONOMICS 2022; 102:103743. [PMID: 35313260 PMCID: PMC9170134 DOI: 10.1016/j.apergo.2022.103743] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 02/24/2022] [Accepted: 03/08/2022] [Indexed: 06/14/2023]
Abstract
Heat stress is associated with workplace injuries, likely through a combination of fatigue, reduced cognitive function, and thermal discomfort. The purpose of this study was to evaluate four cognitive tasks for sensitivity to heat stress. Eight participants performed treadmill exercise followed by assessments of serial reaction time (RT), Stroop effect, verbal delayed memory, and continuous performance working memory in an environmental chamber. A control (21.1 °C) trial, and "Hot 1" and "Hot 2" (both 37.8 °C) trials were run sequentially on two separate days to evaluate the four cognitive tasks. Heat strain (comparing Hot 1 and Hot 2 with the control trial) resulted in impairments in the serial RT test response and Stroop accuracy. Delayed memory was impacted only in the Hot 2 trial compared with the control trial. Given the demonstrated impact of heat on cognitive processes relevant to workers' real-world functioning in the workplace, understanding how to assess and monitor vigilant attention in the workplace is essential.
Collapse
Affiliation(s)
- Kristin Yeoman
- National Institute for Occupational Safety and Health, 315 E. Montgomery Ave, Spokane, WA, 99207, USA.
| | - Alyssa Weakley
- University of California Davis School of Medicine, Department of Neurology, 4860 Y St #3900, Sacramento, CA, 95817, USA
| | - Weston DuBose
- National Institute for Occupational Safety and Health, 315 E. Montgomery Ave, Spokane, WA, 99207, USA
| | - Kimberly Honn
- Washington State University Sleep and Performance Research Center & Elson S. Floyd College of Medicine Washington State University, 412 E. Spokane Falls Blvd., Spokane, WA, USA
| | - Timothy McMurry
- University of Virginia Department of Public Health Sciences, PO Box 800717, Charlottesville, VA, 22908, USA
| | - Brianna Eiter
- National Institute for Occupational Safety and Health, 315 E. Montgomery Ave, Spokane, WA, 99207, USA
| | - Brent Baker
- National Institute for Occupational Safety and Health, 1095 Willowdale Road, MS 4020, Morgantown, WV, 26505-2888, USA
| | - Gerald Poplin
- National Institute for Occupational Safety and Health, 315 E. Montgomery Ave, Spokane, WA, 99207, USA
| |
Collapse
|
8
|
Risk of Dehydration Due to Sweating While Wearing Personal 2 Protective Equipment in COVID-19 Clinical Care: A Pilot Study. Healthcare (Basel) 2022; 10:healthcare10020267. [PMID: 35206881 PMCID: PMC8871557 DOI: 10.3390/healthcare10020267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/17/2022] Open
Abstract
Objective: The objectives of this study were (a) to determine the physical impact of the personal protective equipment (PPE) used in COVID-19 care, specifically the impact on the hydration state of the temperature and the comfort of the healthcare workers who use it, and (b) to show the high-fidelity simulated environment as an appropriate place to test the experimental designs to be developed in real environments for COVID-19. Background: All healthcare staff use full PPE in the care of COVID-19 patients. There are problems, such as excessive sweating, which have not been quantified thus far. Methods: A descriptive pilot design was used in a simulated high-fidelity setting. There was paired activity, with mild–moderate physical activity, between 45 and 60 min continuously, with the COVID-19 PPE. Sixteen intensive care nurses were selected. The before–after differential of weight, thirst, weight use of the PPE, body temperature, thermal body image, general and facial warmth sensation, and perspiration sensation were measured. Results: All subjects lost weight in the form of sweat with both PPEs during the simulation scenario, with a mean of 200 g (0.28% of initial weight), and increased thirst sensation. Body thermal image increased by 0.54 °C in people using the full COVID-19 PPE. Conclusions: The use of PPE in the management of critically ill COVID-19 patients generates weight loss related to excessive sweating. The weight loss shown in this pilot test is far from the clinical limits of dehydration. The use of ventilated PPE, such as PAPR, reduce the body temperature and heat sensation experienced by the users of it; at the same time, it improves the comfort of those who wear it. The simulated environment is a suitable place to develop the piloting of applicable research methodologies in future studies in a real environment.
Collapse
|
9
|
Zhang N, Zhang J, Wang X, Li Y, Yan Y, Ma G. Behaviors of Water Intake, Hydration Status, and Related Hydration Biomarkers among Physically Active Male Young Adults in Beijing, China: A Cross-Sectional Study. Int J Clin Pract 2022; 2022:9436186. [PMID: 36320894 PMCID: PMC9592216 DOI: 10.1155/2022/9436186] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 11/26/2022] Open
Abstract
Studies on the water intake of athletes in daily life are insufficient. The objective was to determine the water intake and hydration status among physically active male young adults. In this cross-sectional studies study, 111 physically active male young adults were recruited. The amount of daily total drinking fluid intake (TDF) among participants was recorded and evaluated in real time over 7 days using the "7-day 24-hour fluid intake questionnaire" (liq. In 7). The daily water intake from food (WFF) was calculated using the weighing, duplicate portion, and direct-drying method over 3 days. All urine samples over 3 days were collected, and urine biomarkers were determined. According to 24 h urine osmolality, the participants were divided into three groups with euhydration status, middle hydration, and hypo hydration statuses. Finally, 109 participants completed the study. The median daily total water intake (TWI), TDF, and WFF were 2701, ik1789, and 955 mL, respectively. Among participants, 17 participants (16%) were in euhydration status, 47 participants (43%) were in hypohydration, and 45 participants (41%) were in middle hydration. There were statistical significances in the 24 h urine volume, osmolality, urine specific gravity, and concentrations of K, Na, and Cl in different hydration statuses (χ 2 = 28.212, P < 0.01; χ 2 = 91.341, P < 0.01; χ 2 = 47.721, P < 0.01; χ 2 = 41.548, P < 0.01; χ 2 = 46.863, P < 0.01; and χ 2 = 40.839, P < 0.01). Moderate-intensity correlations were found between the TDF and 24 h urine volume, 24 h urine osmolality, 24 h urine Na concentration, morning urine osmolality, and morning urine Na concentration (r = 0.408, P < 0.01; r = -0.378, P < 0.01; r = -0.325, P < 0.01; r = -0.344, P < 0.01; and r = -0.329, P < 0.01). There were also moderate-intensity correlations between the TDF and 24 h urine osmolality, morning urine osmolality, and morning urine Na concentration (r = -0.365, P < 0.01; r = -0.371, P < 0.01; and r = -0.322, P = 0.01). Increased and higher moderate-intensity correlations were found between plain water and 24 h urine volume, 24 h urine osmolality, 24 h urine K and Na concentration, morning urine osmolality, and morning urine Na concentration (r = 0.374, P < 0.01; r = -0.520, P < 0.01; r = -0.312,P < 0.01; r = -0.355, P < 0.01; r = -0.446, P < 0.01; and r = -0.378, P < 0.01). Insufficient water intake and hypohydration were common among physically active male young adults. The amount and type of water intake were correlated with hydration status and urine biomarkers. The results could provide scientific and accurate references for the development of recommendations on water intake for athletes.
Collapse
Affiliation(s)
- Na Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| | - Jianfen Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| | - Xing Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| | - Yibin Li
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| | - Yi Yan
- College of Sports and Human Sciences, Beijing Sport University, 48 XinXi Road, Hai Dian District, Beijing 100084, China
| | - Guansheng Ma
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| |
Collapse
|
10
|
Ward MK, Yam CMH, Palejwala Z, Wallman K, Taggart SM, Wood FM, Parker SK. An Experimental Simulation of Heat Effects on Cognition and Workload of Surgical Team Members. Ann Surg 2021; 274:e395-e402. [PMID: 33196490 DOI: 10.1097/sla.0000000000004598] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To isolate heat exposure as a cause of cognitive impairment and increased subjective workload in burns surgical teams. SUMMARY OF BACKGROUND DATA Raising ambient temperature of the operating room can improve burns patient outcomes, but risks increased cognitive impairment and workload of surgical team members. Prior research indicates ambient heat exposure depletes physiological and cognitive resources, but these findings have not been studied in the context of burns surgical teams. METHODS Seventeen surgical team members completed 2 surgery simulations of similar complexities in a hot and in a normothermic operating room. During each simulation, participants completed multiple cognitive tests to assess cognitive functioning and the SURG-TLX to self-assess workload. Order effects, core body temperature changes due to menstruation, and circadian rhythms were controlled for in the experimental design. Descriptive statistics, correlations, and mixed ANOVAs were performed to assess relationships between ambient heat exposure with cognitive functioning and perceived workload. RESULTS Heat had a main effect on executive functioning and verbal reasoning. Duration of heat exposure (heat ∗ time) increased response times and negatively impacted executive functioning, spatial planning, and mental rotation. Perceived workload was higher in the hot condition. CONCLUSIONS We provide causal evidence that over time, heat exposure impairs cognitive speed and accuracy, and increases subjective workload. We recommend building on this study to drive best-practices for acute burns surgery and design work to enable burns teams to maintain their cognitive stamina, lower their workload, and improve outcomes for patients and surgeons.
Collapse
Affiliation(s)
- Mary K Ward
- Curtin University, Faculty of Business and Law, Future of Work Institute, Perth, Australia
| | - Cheryl M H Yam
- Curtin University, Faculty of Business and Law, Future of Work Institute, Perth, Australia
| | - Zehra Palejwala
- The University of Western Australia, School of Human Sciences, Perth, Australia
| | - Karen Wallman
- The University of Western Australia, School of Human Sciences, Perth, Australia
| | - Sarah M Taggart
- The University of Western Australia, School of Human Sciences, Perth, Australia
| | - Fiona M Wood
- Burn Injury Research Unit, University of Western Australia, and Burn Service of WA South Metropolitan Health Service, Perth, Australia
| | - Sharon K Parker
- Curtin University, Faculty of Business and Law, Future of Work Institute, Perth, Australia
| |
Collapse
|
11
|
Goodman SPJ, Marino FE. Thirst perception exacerbates objective mental fatigue. Neuropsychologia 2020; 150:107686. [PMID: 33212138 DOI: 10.1016/j.neuropsychologia.2020.107686] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 10/06/2020] [Accepted: 11/10/2020] [Indexed: 11/19/2022]
Abstract
Thirst is represented within the anterior cingulate and insular cortices, and may share some common neuroanatomical structures that are implicated with the regulation of mental fatigue. This novel study investigated whether thirst might modulate the subjective, behavioural, or neurophysiological representations of mental fatigue. In a crossover design, thirst was monitored in 15 males during 60 min of cycling in normothermic conditions. Participants either consumed water to the dictates of their thirst (sated), or fluid was withheld and replaced with periodic salt water mouth rinses (thirst). Following either satiety or thirst, a 60 min modified Stroop task was completed to evoke mental fatigue. Prefrontal cortex (PFC) haemodynamics were monitored throughout the prolonged task, and subjective perceptions of fatigue were reported through a visual analogue scale. Behavioural performance was quantified as the total number of Stroop task iterations completed in the mentally fatiguing task, and by collating response time and accuracy into the inverse efficiency score (IES) for each 5 min interval throughout the task. During thirst, fewer iterations were completed and poorer IES performance was evident toward the latter portion of the mentally fatiguing task. Compensatory elevations in PFC oxyhaemoglobin were produced in each condition, however, differed temporally, and were premature during thirst. A diminished capacity to sustain cognitive performance is likely the product of an inability to preserve the distribution of resources within the prefrontal cortex, due to heightened activation about thirst regulatory centres. These data provide novel insight into the relationship between thirst and mental fatigue, and suggest that drinking to the dictates of thirst may be a pertinent strategy to sustain prolonged cognitive performance.
Collapse
Affiliation(s)
- Stephen P J Goodman
- School of Exercise Science, Sport & Health, Charles Sturt University, Bathurst, Australia; School of Science and Technology, University of New England, Armidale, Australia.
| | - Frank E Marino
- School of Exercise Science, Sport & Health, Charles Sturt University, Bathurst, Australia.
| |
Collapse
|
12
|
Zhang J, Zhang N, He H, Du S, Ma G. Different Amounts of Water Supplementation Improved Cognitive Performance and Mood among Young Adults after 12 h Water Restriction in Baoding, China: A Randomized Controlled Trial (RCT). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17217792. [PMID: 33114364 PMCID: PMC7662706 DOI: 10.3390/ijerph17217792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 12/26/2022]
Abstract
Water is indispensable to keeping the functions of the human body working properly, including that of the brain. The purpose of this research was to explore the impacts of water supplementation on cognitive performance and mood, and to determine the optimum amount of water to alleviate detriments of dehydration after 12 h water restriction. A randomized controlled trial was implemented among 64 young adults from Baoding, China. Fasting overnight for 12 h, and at 8:00 a.m. on day 2, osmolality of first morning urine and blood, cognitive performance, and mood were assessed as the dehydration test. Then, participants were randomly separated into four groups: water supplementation groups (WS groups 1, 2, and 3 with 500, 200, and 100 mL purified water, respectively) and no water supplementation group (NW group). Participants in WS groups were instructed to drink the water within 10 min, while those in NW group drank no water. After 90 min, the same measurements were taken as the rehydration test. There was significant interaction between TIME and VOLUME in thirst when comparing dehydration with rehydration tests (F = 6.172, p = 0.001). Significant thirst reductions were found in WS group 1 and WS group 2 (p = 0.003; p = 0.041), and a significant increase was found in the NW group (p = 0.039). In the rehydration test, significant interactions between TIME and VOLUME were found in scores of anger, fatigue, and TMD (total mood disturbance) (F = 3.815, p = 0.014; F = 10.429, p < 0.001; F = 5.246, p < 0.001), compared to the dehydration test. Scores of anger were only decreased in WS group 2 (p = 0.025), and scores of fatigue and TMD decreased in WS group 1 and WS group 2 (all p < 0.05). Significant interaction between TIME and VOLUME was only found for operation span test scores (F = 2.816, p = 0.047), with scores being only higher in WS group 1 in the rehydration test compared to the dehydration test (p = 0.003). Comparing WS group 1 and WS group 2, scores of thirst, fatigue, and TMD did not differ significantly (p > 0.05). Water supplementation improved working memory and attenuated anger, fatigue, and TMD. A small amount of water (200 mL) was sufficient to attenuate thirst, anger, fatigue, and TMD of young adults, but the larger volume (500 mL) appeared to be necessary to improve working memory. The amount of 500 mL was the optimum volume to improve the cognitive performance and mood among young adults.
Collapse
Affiliation(s)
- Jianfen Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100191, China; (J.Z.); (N.Z.); (H.H.)
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing 100191, China
| | - Na Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100191, China; (J.Z.); (N.Z.); (H.H.)
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing 100191, China
| | - Hairong He
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100191, China; (J.Z.); (N.Z.); (H.H.)
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing 100191, China
| | - Songming Du
- Chinese Nutrition Society, Beijing 100053, China;
| | - Guansheng Ma
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100191, China; (J.Z.); (N.Z.); (H.H.)
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, Beijing 100191, China
- Correspondence: ; Tel./Fax: +86-10-8280-5266
| |
Collapse
|
13
|
Donnan K, Williams EL, Stanger N. The Effects of Heat Exposure During Intermittent Exercise on Physical and Cognitive Performance Among Team Sport Athletes. Percept Mot Skills 2020; 128:439-466. [PMID: 33076764 PMCID: PMC7859587 DOI: 10.1177/0031512520966522] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study investigated the effects of heat exposure on physical and
cognitive performance during an intermittent exercise protocol so as
to reflect the incremental fatigue experienced during team sports.
Twelve well-trained male team sport players completed an 80-minute
cycling intermittent sprint protocol (CISP), alongside computerized
vigilance and congruent (i.e., simple) and incongruent (i.e., complex)
Stroop tasks of cognitive functioning, in two counterbalanced
temperature conditions; hot (32°C[50%rh]) and control (18°C[50%rh]).
Incongruent Stroop accuracy declined over time
(p = .002), specifically in the second
(Mdiff = –3.75,
SD = 0.90%, p = .009) and
third (Mdiff = –4.58,
SD = 1.22%, p = .019) quarters
compared to the first quarter of the CISP; but there were no
differences between temperature conditions. Congruent Stroop reaction
time (RT) was quicker in the second quarter of exercise in the hot
condition (M = 561.99,
SD = 112.93 ms) compared to the control condition
(M=617.80, SD = 139.71 ms;
p = .022), but no differences were found for
congruent Stroop accuracy nor vigilance measures. Additionally, peak
power output was lower during the third quarter of the CISP in the hot
condition (M = 861.31,
SD = 105.20 W) compared to the control condition
(M = 900.68, SD = 114.84 W;
p < .001). Plasma normetanephrine and
metanephrine concentrations increased from pre- to post-CISP
(Mdiff = +616.90,
SD = 306.99, p < .001; and
Mdiff = +151.23,
SD = 130.32, p = .002,
respectively), with a marginal interaction suggesting a higher
normetanephrine increase from pre- to post-CISP in the hot versus the
control condition (p = .070). Our findings suggest
that accuracy for more complex decisions suffered during prolonged
high-intensity intermittent exercise, perhaps due to exercise-induced
catecholamine increases. Athletes may have also reduced physical
effort under increased heat exposure, indicating how cognitive
performance may be sustained in physically demanding environments.
Collapse
Affiliation(s)
- Kate Donnan
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
| | - Emily L Williams
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
| | - Nicholas Stanger
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
| |
Collapse
|
14
|
Driscoll RL, McCarthy DG, Palmer MS, Spriet LL. Mild dehydration impaired intermittent sprint performance and thermoregulation in females. Appl Physiol Nutr Metab 2020; 45:1045-1048. [PMID: 32392422 DOI: 10.1139/apnm-2020-0040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of mild dehydration during ice hockey are well-studied in males but not females. In a randomized, crossover design, 11 female varsity hockey players drank no fluid (1.7% ± 0.3% body mass loss) or water to maintain hydration during simulated-hockey exercise. Core temperature (P < 0.01) and perceived fatigue (P = 0.02) were higher and sprint power lower (P < 0.01) when mildly dehydrated. Thus, mild dehydration may impair hockey performance and thermoregulation while increasing perceived fatigue in females. Novelty Female stop-and-go sport athletes may benefit their in-game sprint performance and thermoregulation by following personalized in-game hydration to prevent becoming mildly dehydrated.
Collapse
Affiliation(s)
- Rachel L Driscoll
- Department of Psychology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Devin G McCarthy
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Matthew S Palmer
- Department of Human Kinetics, St. Francis Xavier University, Antigonish, NS B2G 2W5, Canada
| | - Lawrence L Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| |
Collapse
|
15
|
Hu S, Maeda T. Productivity and physiological responses during exposure to varying air temperatures and clothing conditions. INDOOR AIR 2020; 30:251-263. [PMID: 31755604 DOI: 10.1111/ina.12628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/22/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
This study assessed the effects of clothing and air temperature combinations on workplace productivity and physiological response. Ten male Japanese subjects were exposed to six combinations of clothing (0.3 clo and 0.9 clo) and air temperature (16°C, 26°C, and 36°C) during which cognitive performance (Bourdon and calculation tests), manual motor performance (finger-tapping test), and physiological responses (heart rate, blood pressure, and skin and oral temperatures) were measured. Both cold exposure and lower clothing levels likely increased the Bourdon test performance. Calculation test performance tended to be affected by exposure to cold or neutral temperatures at the beginning of the test. Cold exposure undermined manual motor performance (especially when combined with fewer clothing items) while heat exposure significantly increased heart rate. Both cold exposure and higher clothing level during heat exposure increased blood pressure. Body temperature, particularly mean skin temperature, increased with higher air temperature and was significantly influenced by clothing insulation during cold exposure. These results provide novel evidence for the effects of clothing and air temperature (particularly cold) on human productivity and physiological responses in humans.
Collapse
Affiliation(s)
- Shaoying Hu
- Laboratory of Environmental Ergonomics, Graduate School of Design, Kyushu University, Fukuoka, Japan
| | - Takafumi Maeda
- Department of Human Science, Faculty of Design, Kyushu University, Fukuoka, Japan
| |
Collapse
|
16
|
Tan XR, Low ICC, Stephenson MC, Kok T, Nolte HW, Soong TW, Lee JKW. Altered brain structure with preserved cortical motor activity after exertional hypohydration: a MRI study. J Appl Physiol (1985) 2019; 127:157-167. [DOI: 10.1152/japplphysiol.00081.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypohydration exceeding 2% body mass can impair endurance capacity. It is postulated that the brain could be perturbed by hypohydration, leading to impaired motor performance. We investigated the neural effects of hypohydration with magnetic resonance imaging (MRI). Ten men were dehydrated to approximately −3% body mass by running on a treadmill at 65% maximal oxygen consumption (V̇o2max) before drinking to replace either 100% [euhydration (EU)] or 0% [hypohydration (HH)] of fluid losses. MRI was performed before start of trial (baseline) and after rehydration phase (post) to evaluate brain structure, cerebral perfusion, and functional activity. Endurance capacity assessed with a time-to-exhaustion run at 75% V̇o2max was reduced with hypohydration (EU: 45.2 ± 9.3 min, HH: 38.4 ± 10.7 min; P = 0.033). Mean heart rates were comparable between trials (EU: 162 ± 5 beats/min, HH: 162 ± 4 beats/min; P = 0.605), but the rate of rise in rectal temperature was higher in HH trials (EU: 0.06 ± 0.01°C/min, HH: 0.07 ± 0.02°C/min; P < 0.01). In HH trials, a reduction in total brain volume (EU: +0.7 ± 0.6%, HH: −0.7 ± 0.9%) with expansion of ventricles (EU: −2.7 ± 1.6%, HH: +3.7 ± 3.3%) was observed, and vice versa in EU trials. Global and regional cerebral perfusion remained unchanged between conditions. Functional activation in the primary motor cortex in left hemisphere during a plantar-flexion task was similar between conditions (EU: +0.10 ± 1.30%, HH: −0.11 ± 0.31%; P = 0.637). Our findings demonstrate that with exertional hypohydration, brain volumes were altered but the motor-related functional activity was unperturbed. NEW & NOTEWORTHY Dehydration occurs rapidly during prolonged or intensive physical activity, leading to hypohydration if fluid replenishment is insufficient to replace sweat losses. Altered hydration status poses an osmotic challenge for the brain, leading to transient fluctuations in brain tissue and ventricle volumes. Therefore, the amount of fluid ingestion during exercise plays a critical role in preserving the integrity of brain architecture. These structural changes, however, did not translate directly to motor functional deficits in a simple motor task.
Collapse
Affiliation(s)
- X. R. Tan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- National University of Singapore Graduate School for Integrative Sciences and Engineering, Singapore, Singapore
| | - I. C. C. Low
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - M. C. Stephenson
- Clinical Imaging Research Centre, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - T. Kok
- Clinical Imaging Research Centre, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - H. W. Nolte
- Movement Physiology Research Laboratory, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand Medical School, Johannesburg, South Africa
| | - T. W. Soong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- National University of Singapore Graduate School for Integrative Sciences and Engineering, Singapore, Singapore
| | - J. K. W. Lee
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Global Asia Institute, National University of Singapore, Singapore, Singapore
- N.1 Institute for Health, National University of Singapore, Singapore, Singapore
| |
Collapse
|
17
|
Goodman SP, Moreland AT, Marino FE. The effect of active hypohydration on cognitive function: A systematic review and meta-analysis. Physiol Behav 2019; 204:297-308. [DOI: 10.1016/j.physbeh.2019.03.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 02/12/2019] [Accepted: 03/11/2019] [Indexed: 12/14/2022]
|
18
|
Maintaining Euhydration Preserves Cognitive Performance, But Is Not Superior to Hypohydration. JOURNAL OF COGNITIVE ENHANCEMENT 2019. [DOI: 10.1007/s41465-019-00123-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|