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Vogel RM, Varone N, Clark C, Ramirez K, Ross MLR, Swann C, Stevens CJ. A Menthol-Enhanced "Cooling" Energy Gel Does Not Influence Laboratory Time Trial Performance in Trained Runners. Nutrients 2023; 15:3379. [PMID: 37571316 PMCID: PMC10420894 DOI: 10.3390/nu15153379] [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: 06/15/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/13/2023] Open
Abstract
l-menthol (menthol) is an organic compound derived from peppermint which imparts a refreshing mint flavor and aroma to oral hygiene products, chewing gum, and topical analgesics. Menthol has been identified as a non-thermal sensory cooling strategy for athletes when ingested or mouth-rinsed during exercise in hot environments. Therefore, sports nutrition products delivering a controlled concentration of menthol could be beneficial for athletes exercising in the heat. We sought to test the performance and perceptual outcomes of a novel menthol energy gel during treadmill running in the heat (33 °C, 49% RH). Fourteen trained runners (mean ± SD; age: 31 ± 6 years, VO2max: 56.5 ± 10.1 mL·kg-1·min-1, BMI: 23.2 ± 2.4 kg/m2; six female) participated in a randomized, crossover, double-blind, and placebo-controlled study. A menthol-enhanced energy gel (0.5% concentration; MEN) or flavor-matched placebo (PLA) was ingested 5 min before and again at 20 and 40 min of a 40 min treadmill exercise preload at 60% VO2max, followed by a 20 min self-paced time trial. The total distance, vertical distance, perceptual measures (thermal comfort, thermal sensation, rating of perceived exertion, and affect), and cognitive performance via computerized neurocognitive assessment were measured. No difference between 20 min self-paced time trial total distance (MEN: 4.22 ± 0.54 km, PLA: 4.22 ± 0.55 km, p = 0.867), vertical distance (MEN: 49.2 ± 24.6 m, PLA: 44.4 ± 11.4 m, p = 0.516), or any perceptual measures was observed (all p > 0.05). Cognitive performance was not different between the trials (all p > 0.05). These results suggest that a menthol energy gel is not superior to a non-menthol gel in terms of performance or perception during treadmill running in the heat. More research is needed to confirm whether these findings translate to ecologically valid settings, including outdoor exercise in ambient heat and during competition.
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Affiliation(s)
- Roxanne M. Vogel
- Physical Activity, Sport and Exercise Research (PASER) Theme, Faculty of Health, Southern Cross University, Coffs Harbour, NSW 2450, Australia
- GU Energy Labs, Berkeley, CA 94710, USA
| | - Nicole Varone
- School of Health Promotion & Kinesiology, Texas Woman’s University, Denton, TX 76201, USA (K.R.)
| | - Cayla Clark
- School of Health Promotion & Kinesiology, Texas Woman’s University, Denton, TX 76201, USA (K.R.)
| | - Kyndall Ramirez
- School of Health Promotion & Kinesiology, Texas Woman’s University, Denton, TX 76201, USA (K.R.)
| | | | - Christian Swann
- Physical Activity, Sport and Exercise Research (PASER) Theme, Faculty of Health, Southern Cross University, Coffs Harbour, NSW 2450, Australia
| | - Christopher J. Stevens
- Physical Activity, Sport and Exercise Research (PASER) Theme, Faculty of Health, Southern Cross University, Coffs Harbour, NSW 2450, Australia
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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.
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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
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Morrissey MC, Brewer GJ, Williams WJ, Quinn T, Casa DJ. Impact of occupational heat stress on worker productivity and economic cost. Am J Ind Med 2021; 64:981-988. [PMID: 34590324 DOI: 10.1002/ajim.23297] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/12/2021] [Accepted: 09/13/2021] [Indexed: 12/16/2022]
Abstract
Heat stress is a growing concern in the occupational setting as it endangers worker health, safety, and productivity. Heat-related reductions in physical work capacity and missed workdays directly and indirectly cause productivity losses and may substantially affect the economic wellbeing of the organization. This review highlights the physiological, physical, psychological, and financial harms of heat stress on worker productivity and proposes strategies to quantify heat-related productivity losses. Heat stress produces a vicious-cycle feedback loop that result in adverse outcomes on worker health, safety, and productivity. We propose a theoretical model for implementing an occupational heat safety plan that disrupts this loop, preventing heat-related productivity losses while improving worker health and safety.
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Affiliation(s)
- Margaret C. Morrissey
- Department of Kinesiology, Korey Stringer Institute University of Connecticut Storrs Connecticut USA
| | - Gabrielle J. Brewer
- Department of Kinesiology, Korey Stringer Institute University of Connecticut Storrs Connecticut USA
| | - Warren Jon Williams
- Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH) National Personal Protective Technology Laboratory (NPPTL) Pittsburgh Pennsylvania USA
| | - Tyler Quinn
- Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH) National Personal Protective Technology Laboratory (NPPTL) Pittsburgh Pennsylvania USA
| | - Douglas J. Casa
- Department of Kinesiology, Korey Stringer Institute University of Connecticut Storrs Connecticut USA
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Perroni F, Cardinali L, Cignitti L, Gobbi E, Grugni F, Amatori S, Rocchi MBL, Grandinetti L, Lunetta F, Stocchi V, Baldari C, Sisti D, Guidetti L. Are there sex differences in physiological parameters and reaction time responses to overload in firefighters? PLoS One 2021; 16:e0249559. [PMID: 33939690 PMCID: PMC8092788 DOI: 10.1371/journal.pone.0249559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 03/20/2021] [Indexed: 01/01/2023] Open
Abstract
Male and female firefighters work side-by-side in the same in strenuous and risky conditions. Anthropometrics, physiological, and reaction time (mean of reaction time -MRT-, and errors made -E) parameters of 12 Female and 13 Male firefighters were compared. Effect of overload (step test with and without equipment) on the MRT and E were analyzed on 3 trials (T1 = 1-1s, T2 = 0.5-1s, T3 = 0.5–0.5s), compared with a pre-test condition (basal). T-test between males and females was applied to assess differences (p<0.05) in all parameters. ANOVA with repeated measures and Bonferroni on 3 conditions of step test between males and females was applied in reaction time variables. Between MRT and E, in T1, T2 and T3 trials and the 3 test conditions, ANCOVA models with interactions were used. Differences (p<0.05) in anthropometric, physiological and reaction time data emerged across groups, and on the 3rd trials (T3 vs T1 and T2) in reaction time parameters of each group. ANCOVA showed differences (p<0.001) in E among trials. Post hoc showed significant differences in T1vsT3 and T1vsT2. MRT x trial interaction was extremely significant (P<0.001). Implementing fitness and reaction time exercise programs is important to decrease the injury risk and increase work capacity in firefighters with reference to female workers.
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Affiliation(s)
- Fabrizio Perroni
- Department of Biomolecular Sciences, Section of Exercise and Health Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Ludovica Cardinali
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | | | - Erica Gobbi
- Department of Biomolecular Sciences, Section of Exercise and Health Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | | | - Stefano Amatori
- Department of Biomolecular Sciences, Service of Biostatistics, University of Urbino Carlo Bo, Urbino, Italy
| | - Marco Bruno Luigi Rocchi
- Department of Biomolecular Sciences, Service of Biostatistics, University of Urbino Carlo Bo, Urbino, Italy
| | | | | | - Vilberto Stocchi
- Department of Biomolecular Sciences, Section of Exercise and Health Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Carlo Baldari
- Faculty of Psychology, eCampus University, Novedrate, Como, Italy
| | - Davide Sisti
- Department of Biomolecular Sciences, Service of Biostatistics, University of Urbino Carlo Bo, Urbino, Italy
| | - Laura Guidetti
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
- Department Unicusano, University "Niccolò Cusano", Rome, Italy
- * E-mail:
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Guest NS, VanDusseldorp TA, Nelson MT, Grgic J, Schoenfeld BJ, Jenkins NDM, Arent SM, Antonio J, Stout JR, Trexler ET, Smith-Ryan AE, Goldstein ER, Kalman DS, Campbell BI. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr 2021; 18:1. [PMID: 33388079 PMCID: PMC7777221 DOI: 10.1186/s12970-020-00383-4] [Citation(s) in RCA: 191] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 10/31/2020] [Indexed: 12/13/2022] Open
Abstract
Following critical evaluation of the available literature to date, The International Society of Sports Nutrition (ISSN) position regarding caffeine intake is as follows: 1. Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions. 2. Aerobic endurance appears to be the form of exercise with the most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals. 3. Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3-6 mg/kg body mass. Minimal effective doses of caffeine currently remain unclear but they may be as low as 2 mg/kg body mass. Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects and do not seem to be required to elicit an ergogenic effect. 4. The most commonly used timing of caffeine supplementation is 60 min pre-exercise. Optimal timing of caffeine ingestion likely depends on the source of caffeine. For example, as compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption to the start of the exercise session. 5. Caffeine appears to improve physical performance in both trained and untrained individuals. 6. Inter-individual differences in sport and exercise performance as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion may be attributed to genetic variation associated with caffeine metabolism, and physical and psychological response. Other factors such as habitual caffeine intake also may play a role in between-individual response variation. 7. Caffeine has been shown to be ergogenic for cognitive function, including attention and vigilance, in most individuals. 8. Caffeine may improve cognitive and physical performance in some individuals under conditions of sleep deprivation. 9. The use of caffeine in conjunction with endurance exercise in the heat and at altitude is well supported when dosages range from 3 to 6 mg/kg and 4-6 mg/kg, respectively. 10. Alternative sources of caffeine such as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic exercise. 11. Energy drinks and pre-workout supplements containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.
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Affiliation(s)
- Nanci S Guest
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 1 King's College Circle, Room 5326A, Toronto, ON, M5S 1A8, Canada.
| | - Trisha A VanDusseldorp
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, GA, 30144, USA
| | | | - Jozo Grgic
- Institute for Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Brad J Schoenfeld
- Department of Health Sciences, CUNY Lehman College, Bronx, NY, 10468, USA
| | - Nathaniel D M Jenkins
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, 52240, USA
| | - Shawn M Arent
- Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Colombia, SC, 29208, USA
- School of Social and Health Sciences, Leeds Trinity University, Leeds, UK
| | - Jose Antonio
- Exercise and Sport Science, Nova Southeastern University, Davie, FL, 33314, USA
| | - Jeffrey R Stout
- Institue of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, 32816, USA
| | | | - Abbie E Smith-Ryan
- Department of Exercise and Sport Science, Applied Physiology Laboratory, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Erica R Goldstein
- Institue of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, 32816, USA
| | - Douglas S Kalman
- Nutrion Department, College of Osteopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL, 33314, USA
- Scientific Affairs. Nutrasource, Guelph, ON, Canada
| | - Bill I Campbell
- Performance & Physique Enhancement Laboratory, University of South Florida, Tampa, FL, 33612, USA
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The Effects of Live-Fire Drills on Visual and Auditory Cognitive Performance among Firefighters. Ann Glob Health 2020; 86:144. [PMID: 33262933 PMCID: PMC7678564 DOI: 10.5334/aogh.2626] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Introduction: The nature of firefighters’ work is characterized by its unexpected emergencies, sleep deprivation, night shift schedules, and smoke exposure during firefighting. Methods: Eighteen firefighters were involved in simulated live-fire activities. Firefighters’ health status in terms of cardiovascular and mental conditions was checked by a physician and through reviewing their medical records. Firefighters’ cognitive functions were evaluated by visual and auditory continuous performance tests (VCPT and ACPT) and paced visual and auditory serial addition tests (PVSAT and PASAT). Results: VCPT and ACPT scores were lower after the activity relative to baseline. The results revealed that ACPT appears to be more difficult than VCPT. Also, PVSAT and PASAT scores decreased significantly after the experiment. PASAT scores following firefighting tasks experienced a more significant decline compared to those of the PVSAT. Conclusions: These findings suggest that firefighters have visual and auditory cognitive function problems following firefighting activities. In conclusion, auditory cognitive function was more influenced than the visual ability as a result of the experiment.
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Saldaris JM, Landers GJ, Lay BS. Enhanced Decision Making and Working Memory During Exercise in the Heat With Crushed Ice Ingestion. Int J Sports Physiol Perform 2020; 15:503-510. [PMID: 31711038 DOI: 10.1123/ijspp.2019-0234] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/22/2019] [Accepted: 07/12/2019] [Indexed: 11/18/2022]
Abstract
PURPOSE To examine the effects of precooling via crushed ice ingestion on cognitive function during exercise in the heat. METHODS Eleven active men ingested either 7 g·kg-1 of crushed ice (ICE) or thermoneutral water (CON) 30 minutes before running 90 minutes on a treadmill at a velocity equivalent to 65% VO2peak in hot and humid conditions (35.0°C [0.5°C], 53.1% [3.9%] relative humidity). Participants completed 3 cognitive tasks to investigate decision making (8-choice reaction time [CRT]), working memory (serial seven [S7]), and executive control (color multisource interference task [cMSIT]) on arrival, after precooling, and after running. RESULTS Precooling significantly decreased preexercise core (Tcore) and forehead skin temperature in ICE compared with CON, respectively (Tcore 0.8°C [0.4°C], -0.2°C [0.1°C]; Thead -0.5°C [0.4°C], 0.2°C [0.8°C]; P ≤ .05). Postrun, ICE significantly reduced errors compared with CON for CRT (P ≤ .05; d = 0.90; 90% confidence interval, 0.13-1.60) and S7 (P ≤ .05; d = 1.05; 90% confidence interval, 0.26-1.75). Thermal sensation was lower after precooling with ICE (P ≤ .05), but no significant differences were recorded between conditions for cMSIT errors, skin temperature, heart rate, or ratings of perceived exertion or perceived thirst (P > .05). CONCLUSIONS Precooling via ICE maintained cognitive accuracy in decision making and working memory during exercise in the heat. Thus, ICE may have the potential to improve sporting performance by resisting deleterious effects of exercise in a hot and humid environment on cognitive function.
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Saldaris JM, Landers GJ, Lay BS. Physical and perceptual cooling: Improving cognitive function, mood disturbance and time to fatigue in the heat. Scand J Med Sci Sports 2020; 30:801-811. [DOI: 10.1111/sms.13623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/18/2019] [Accepted: 12/22/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Jacinta M. Saldaris
- School of Human Sciences (Exercise and Sport Science) The University of Western Australia Western Australia Perth Australia
| | - Grant J. Landers
- School of Human Sciences (Exercise and Sport Science) The University of Western Australia Western Australia Perth Australia
| | - Brendan S. Lay
- School of Human Sciences (Exercise and Sport Science) The University of Western Australia Western Australia Perth Australia
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9
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Oral Glutamine Supplement Reduces Subjective Fatigue Ratings during Repeated Bouts of Firefighting Simulations. SAFETY 2019. [DOI: 10.3390/safety5020038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Wildland firefighting requires repetitive (e.g., consecutive work shifts) physical work in dangerous conditions (e.g., heat and pollution). Workers commonly enter these environments in a nonacclimated state, leading to fatigue and heightened injury risk. Strategies to improve tolerance to these stressors are lacking. Purpose: To determine if glutamine ingestion prior to and after consecutive days of firefighting simulations in the heat attenuates subjective ratings of fatigue, and evaluate if results were supported by glutamine-induced upregulation of biological stress responses. Methods: Participants (5 male, 3 female) ingested glutamine (0.15 g/kg/day) or a placebo before and after two consecutive days (separated by 24 h) of firefighter simulations in a heated chamber (35 °C, 35% humidity). Perceived fatigue and biological stress were measured pre-, post-, and 4 h postexercise in each trial. Results: Subjective fatigue was reduced pre-exercise on Day 2 in the glutamine group (p < 0.05). Peripheral mononuclear cell expression of heat shock protein 70 (HSP70) and serum antioxidants were elevated at 4 h postexercise on Day 1 in the glutamine trial (p < 0.05). Conclusions: Ingestion of glutamine before and after repeated firefighter simulations in the heat resulted in reduced subjective fatigue on Day 2, which may be a result of the upregulation of biological stress systems (antioxidants, HSPs). This response may support recovery and improve work performance.
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Abrard S, Bertrand M, De Valence T, Schaupp T. Physiological, cognitive and neuromuscular effects of heat exposure on firefighters after a live training scenario. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2018; 27:185-193. [PMID: 30507358 DOI: 10.1080/10803548.2018.1550899] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This study investigated physiological, cognitive and neuromuscular performances in firefighters after a structural live-fire scenario. Changes in vital signs, environmental parameters and cognitive and neuromuscular performance were measured before and after a live-fire training session in a closed environment, in conditions similar to those one could encounter in a structural fire. Very high ambient temperature peaks were reached during the 30-min sessions. After the session, the forehead temperature was increased by 0.5 °C, mean water body loss was 639 ml and the mean heart rate increase was 7.5 bpm. Mental calculation speed did not vary significantly, however we observed a reduction in reaction time. These findings demonstrated that after 30 min of exposure, heat stress had little impact on firemen. Stress activation seems beneficial after firefighting operations. Normal vital parameters should allow re-engagement for a second firefighting task. This result must be compared with longer exposures.
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Affiliation(s)
- Stanislas Abrard
- Departmental Fire and Rescue Services of Maine-et-Loire (SDIS 49), Health and Medical Rescue Service (SSSM), France.,Anesthesiology and Intensive Care Department, Angers University Hospital, France
| | - Mathieu Bertrand
- Departmental Fire and Rescue Services of Maine-et-Loire (SDIS 49), Prospective Service and Training Engineering, France
| | | | - Thierry Schaupp
- Departmental Fire and Rescue Services of Maine-et-Loire (SDIS 49), Health and Medical Rescue Service (SSSM), France
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11
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Zare S, Hemmatjo R, Allahyari T, Hajaghazadeh M, Hajivandi A, Aghabeigi M, Kazemi R. Comparison of the effect of typical firefighting activities, live fire drills and rescue operations at height on firefighters' physiological responses and cognitive function. ERGONOMICS 2018; 61:1334-1344. [PMID: 29862929 DOI: 10.1080/00140139.2018.1484524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 04/11/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
This study examined the impact of various types of firefighting activities on firefighters' physiological responses and cognitive function. Each firefighter was engaged in three conditions: (1) Live-fire activities (LFA), (2) Typical firefighting activities (TFA), and (3) Rescue operations at height (ROH). The effects of various types of firefighting activities on the physiological responses and cognitive function were evaluated by heart rate (HR), temporal artery temperature (TT), and the correct response (CR) on a cognitive test. The results indicated that, compared to the baseline, physiological response increased, while information processing performance decreased after the activity. Furthermore, HR and TT were significantly lower at the end of the firefighting activity in the LFA (149.33 bpm; 38.08 °C) compared with the TFA (152.22 bpm; 38.17 °C) and ROH (159.28 bpm; 38.24 °C) conditions. Also, CR was significantly higher at the end of the activity in the LFA and TFA compared with the ROH condition. The results showed that rescue at height was more intensive than the other firefighting tasks in decreasing physiological and cognitive function capacity after the experiment. Practitioner Summary: We assumed that various types of firefighting activities would have different effects on physiological and cognitive functions during firefighting activities. The Findings suggest that rescue at height operations, performed without the use of special protective equipment, was more influential than other firefighting duties in changing firefighters' physiological and cognitive capacity. Abbreviations: CR: correct response; LFA: live-fire activities; TFA: typical firefighting activities; ROH: rescue operations at height; HR: heart rate; TT: temporal artery tempearture; PASAT: pased auditory serila addition teat; FPC: firefighting protective clothing.
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Affiliation(s)
- Sajad Zare
- a Department of Occupational Health, School of Public Health , Kerman University of Medical Sciences , Kerman , Iran
| | - Rasoul Hemmatjo
- b Department of Occupational Health Engineering, School of Health , Urmia University of Medical Sciences , Urmia , Iran
| | - Teimour Allahyari
- c Department of Occupational Health, School of Health , Urmia University of Medical Sciences , Urmia , Iran
| | - Mohammad Hajaghazadeh
- d Department of Occupational Health Engineering, School of Public Health , Urmia University of Medical Sciences , Urmia , Iran
| | - Abdollah Hajivandi
- e Department of Biostatistics, School of Public Health , Bushehr University of Medical Sciences , Bushehr , Iran
| | - Mandana Aghabeigi
- f Department National Petrochemical Company of Tehran , Tehran , Iran
| | - Reza Kazemi
- g Department of Ergonomics, School of Public Health , Shiraz University of Medical Sciences , Iran
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Abstract
The application of menthol has recently been researched as a performance-enhancing aid for various aspects of athletic performance including endurance, speed, strength and joint range of motion. A range of application methods has been used including a mouth rinse, ingestion of a beverage containing menthol or external application to the skin or clothing via a gel or spray. The majority of research has focussed on the use of menthol to impart a cooling sensation on athletes performing endurance exercise in the heat. In this situation, menthol appears to have the greatest beneficial effect on performance when applied internally. In contrast, the majority of investigations into the external application of menthol demonstrated no performance benefit. While studies are limited in number, menthol has not yet proven to be beneficial for speed or strength, and only effective at increasing joint range of motion following exercise that induced delayed-onset muscle soreness. Internal application of menthol may provoke such performance-enhancing effects via mechanisms related to its thermal, ventilatory, analgesic and arousing properties. Future research should focus on well-trained subjects and investigate the addition of menthol to nutritional sports products.
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Affiliation(s)
- Christopher J Stevens
- School of Health and Human Sciences, Southern Cross University, Hogbin Drive, Coffs Harbour, NSW, 2450, Australia.
| | - Russ Best
- School of Social Sciences, Business and Law, Teesside University, Middlesbrough, UK
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13
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Hemmatjo R, Motamedzade M, Aliabadi M, Kalatpour O, Farhadian M. The Effect of Various Hot Environments on Physiological Responses and Information Processing Performance Following Firefighting Activities in a Smoke-Diving Room. Saf Health Work 2017; 8:386-392. [PMID: 29276638 PMCID: PMC5715452 DOI: 10.1016/j.shaw.2017.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 02/15/2017] [Indexed: 11/30/2022] Open
Abstract
Background Fire service workers often implement multiple duties in the emergency conditions, with such duties being mostly conducted in various ambient temperatures. Methods The aim of the current study was to assess the firefighters' physiological responses, information processing, and working memory prior to and following simulated firefighting activities in three different hot environments. Seventeen healthy male firefighters performed simulated firefighting tasks in three separate conditions, namely (1) low heat (LH; 29–31°C, 55–60% relative humidity), (2) moderate heat (MH; 32–34°C, 55–60% relative humidity), and (3) severe heat (SH; 35–37°C, 55–60% relative humidity). It took about 45–50 minutes for each firefighter to finish all defined firefighting activities and the paced auditory serial addition test (PASAT). Results At the end of all the three experimental conditions, heart rate (HR) and tympanic temperature (TT) increased, while PASAT scores as a measure of information processing performance decreased relative to baseline. HR and TT were significantly higher at the end of the experiment in the SH (159.41 ± 4.25 beats/min; 38.22 ± 0.10°C) compared with the MH (156.59 ± 3.77 beats/min; 38.20 ± 0.10°C) and LH (154.24 ± 4.67 beats/min; 38.17 ± 0.10°C) conditions (p < 0.05). There was no significant difference in PASAT scores between LH and MH (p > 0.05). Nonetheless, there was a measurable difference in PASAT scores between LH and SH (p < 0.05). Conclusion These consequences demonstrate that ambient temperature is effective in raising the physiological responses following firefighting activities. It is therefore argued that further increase of ambient temperature can impact firefighters' information processing and working memory during firefighting activity.
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Affiliation(s)
- Rasoul Hemmatjo
- Department of Occupational Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Majid Motamedzade
- Department of Ergonomics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
- Corresponding author. Department of Ergonomics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.Department of ErgonomicsSchool of Public HealthHamadan University of Medical SciencesHamadanIran
| | - Mohsen Aliabadi
- Department of Occupational Health, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Omid Kalatpour
- Department of Occupational Health, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Maryam Farhadian
- Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
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Wikoff D, Welsh BT, Henderson R, Brorby GP, Britt J, Myers E, Goldberger J, Lieberman HR, O'Brien C, Peck J, Tenenbein M, Weaver C, Harvey S, Urban J, Doepker C. Systematic review of the potential adverse effects of caffeine consumption in healthy adults, pregnant women, adolescents, and children. Food Chem Toxicol 2017; 109:585-648. [DOI: 10.1016/j.fct.2017.04.002] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 03/21/2017] [Accepted: 04/03/2017] [Indexed: 12/21/2022]
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Wallace PJ, McKinlay BJ, Coletta NA, Vlaar JI, Taber MJ, Wilson PM, Cheung SS. Effects of Motivational Self-Talk on Endurance and Cognitive Performance in the Heat. Med Sci Sports Exerc 2017; 49:191-199. [PMID: 27580154 DOI: 10.1249/mss.0000000000001087] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We tested the effectiveness of a 2-wk motivational self-talk (MST) intervention-specific to heat tolerance-on endurance capacity and cognitive function in the heat. METHODS Eighteen trained male (n = 14) and female (n = 4) cyclists randomly received 2 wk of MST training (n = 9) or a control regimen (CON, n = 9). The experimental protocol was a PRE/POST design consisting of 30 min of cycling at 60% peak power output (PPO) in the heat (35°C, 50% relative humidity, ~3.0 m·s airflow), a 30-min rest period, followed by a time to exhaustion (TTE) test at 80% PPO, and an identical rest period. Executive function, reaction time, and working memory were tested at baseline and each rest period. Key measures included TTE, speed and accuracy on the cognitive tests, rectal temperature, HR, oxygen consumption, and RPE. RESULTS Group (MST vs CON) × test (PRE vs POST) × time repeated-measures ANOVA revealed that MST significantly increased TTE from PRE (487 ± 173 s) to POST (679 ± 251 s, P = 0.021) concurrent with a higher terminating rectal temperature (PRE, 38.5°C ± 0.2°C; POST, 38.8°C ± 0.4°C; P = 0.023); no TTE (PRE, 531 ± 178 s; POST, 510 ± 216 s; P = 0.28) or rectal temperature (PRE, 38.4°C ± 0.3°C; POST, 38.4°C ± 0.2°C; P = 1.000) changes were found in CON. MST significantly improved both speed and accuracy for executive function from PRE/POST, with no PRE/POST differences for CON on any cognitive measure. There were no interactions (all P > 0.05) for other key measures. CONCLUSION Motivational self-talk is effective in altering the internal psychophysiological control of exercise and plays a role in improving endurance capacity and executive function in the heat.
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Affiliation(s)
- Phillip J Wallace
- 1Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Ontario, CANADA; 2Applied Physiology Lab, Department of Kinesiology, Brock University, St. Catharines, Ontario, CANADA; 3Falck Safety Services Canada, Mount Pearl, Newfoundland and Labrador, CANADA; and 4Behavioural Health Sciences Research Lab, Department of Kinesiology, Brock University, St. Catharines, Ontario, CANADA
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Hemmatjo R, Motamedzade M, Aliabadi M, Kalatpour O, Farhadian M. The effect of artificial smoke compound on physiological responses, cognitive functions and work performance during firefighting activities in a smoke-diving room: an intervention study. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2017; 24:358-365. [PMID: 28278005 DOI: 10.1080/10803548.2017.1299995] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This study investigated the combined effect of firefighting operations and exposure to smoke on physiological responses, cognitive functions and physical performance among firefighters. Each firefighter was engaged in two experimental conditions: (a) without artificial smoke, control (NS); (b) with artificial smoke (WS). The results of data analysis revealed that heart rate and body temperature increased significantly after the firefighting activities in the two conditions relative to baseline. In addition, reaction time (RT) and correct response (CR) decreased after the activity relative to baseline and there was a significant difference in RT and CR between the NS and WS conditions. There was also a significant difference in performance time between the NS and WS conditions. These findings demonstrated that a smoke compound has an insignificant effect on physiological responses during firefighting activity. On the contrary, the smoke compound has a detrimental influence on cognitive and physical performance.
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Affiliation(s)
- Rasoul Hemmatjo
- a Department of Occupational Health , Hamadan University of Medical Sciences , Iran
| | - Majid Motamedzade
- b Ergonomics Department , Hamadan University of Medical Sciences , Iran
| | - Mohsen Aliabadi
- c Department of Occupational Health , Hamadan University of Medical Science , Iran
| | - Omid Kalatpour
- c Department of Occupational Health , Hamadan University of Medical Science , Iran
| | - Maryam Farhadian
- d Department of Biostatistics , Hamadan University of Medical Science , Iran
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Hemmatjo R, Motamedzade M, Aliabadi M, Kalatpour O, Farhadian M. The effect of practical cooling strategies on physiological response and cognitive function during simulated firefighting tasks. Health Promot Perspect 2017; 7:66-73. [PMID: 28326286 PMCID: PMC5350552 DOI: 10.15171/hpp.2017.13] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 01/19/2017] [Indexed: 11/09/2022] Open
Abstract
Background: Firefighters often perform multiple tasks during firefighting operations under unknown and unpredictable conditions in hot and hostile environments. Methods: In this interventional study each firefighters engaged in 4 conditions: namely (1) no cooling device; control (NC), (2) cooling gel (CG), (3) cool vest (CV), and (4) CG+CV. Cooling effects of the employed interventions were evaluated based on heart rate (HR), temporal temperature (TT), reaction time (RT), and the correct response (CR). Results: HR and TT values for use of CG+CV (147.47 bpm [SD 4.8]; 37.88°C [SD 0.20]) and CV bpm (147.53 [SD 4.67]; 37.90°C [SD 0.22]) were significantly lower than the CG (153.67 bpm [SD 4.82]; 38.10°C [SD 0.22]) and NC (154.4 bpm [SD 4.91]; 38.11°C [SD 0.23]) at the end of the activity. RT and CR for use of CG + CV (389.87 ms [SD 6.12]; 143.53 [SD 1.24]) and CV (389.53 ms [SD 6.24]; 143.47 [SD 1.18]) were significantly higher than the CG (385.73 [SD 7.25] ms; 143.07 [SD 0.88]) and NC (385.67 ms [SD 7.19]; 143.00 [SD 0.84]) at the end of the activity. Conclusion: It is concluded that CV was more effective than the CG in attenuating physiological responses and cognitive functions during firefighting operations. Furthermore, combining CV with CG provides no additional benefit.
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Affiliation(s)
- Rasoul Hemmatjo
- Department of Occupational Health, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Majid Motamedzade
- Department of Ergonomics, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohsen Aliabadi
- Department of Occupational Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Omid Kalatpour
- Department of Occupational Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Maryam Farhadian
- Department of Biostatistics, Hamadan University of Medical Sciences, Hamadan, Iran
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Taylor L, Watkins SL, Marshall H, Dascombe BJ, Foster J. The Impact of Different Environmental Conditions on Cognitive Function: A Focused Review. Front Physiol 2016; 6:372. [PMID: 26779029 PMCID: PMC4701920 DOI: 10.3389/fphys.2015.00372] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 11/20/2015] [Indexed: 01/08/2023] Open
Abstract
Cognitive function defines performance in objective tasks that require conscious mental effort. Extreme environments, namely heat, hypoxia, and cold can all alter human cognitive function due to a variety of psychological and/or biological processes. The aims of this Focused Review were to discuss; (1) the current state of knowledge on the effects of heat, hypoxic and cold stress on cognitive function, (2) the potential mechanisms underpinning these alterations, and (3) plausible interventions that may maintain cognitive function upon exposure to each of these environmental stressors. The available evidence suggests that the effects of heat, hypoxia, and cold stress on cognitive function are both task and severity dependent. Complex tasks are particularly vulnerable to extreme heat stress, whereas both simple and complex task performance appear to be vulnerable at even at moderate altitudes. Cold stress also appears to negatively impact both simple and complex task performance, however, the research in this area is sparse in comparison to heat and hypoxia. In summary, this focused review provides updated knowledge regarding the effects of extreme environmental stressors on cognitive function and their biological underpinnings. Tyrosine supplementation may help individuals maintain cognitive function in very hot, hypoxic, and/or cold conditions. However, more research is needed to clarify these and other postulated interventions.
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Affiliation(s)
- Lee Taylor
- ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research CentreDoha, Qatar
- Applied Sport and Exercise Physiology Research Group, Department of Sport Science and Physical Activity, Institute for Sport and Physical Activity Research, University of BedfordshireBedford, UK
| | - Samuel L. Watkins
- Applied Sport and Exercise Physiology Research Group, Department of Sport Science and Physical Activity, Institute for Sport and Physical Activity Research, University of BedfordshireBedford, UK
| | - Hannah Marshall
- Applied Sport and Exercise Physiology Research Group, Department of Sport Science and Physical Activity, Institute for Sport and Physical Activity Research, University of BedfordshireBedford, UK
| | - Ben J. Dascombe
- Applied Sport Science and Exercise Testing Laboratory, Faculty of Science and Information Technology, University of NewcastleOurimbah, NSW, Australia
| | - Josh Foster
- Applied Sport and Exercise Physiology Research Group, Department of Sport Science and Physical Activity, Institute for Sport and Physical Activity Research, University of BedfordshireBedford, UK
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Young PM, St Clair Gibson A, Partington E, Partington S, Wetherell MA. Psychophysiological responses in experienced firefighters undertaking repeated self-contained breathing apparatus tasks. ERGONOMICS 2014; 57:1898-1906. [PMID: 25363022 DOI: 10.1080/00140139.2014.945490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In order to safely and effectively extinguish fires and rescue life, firefighters are required to routinely wear self-contained breathing apparatus (SCBA), yet little is known about the specific physiological and psychological demands associated with repeated exposure to tasks that require SCBA. A total of 12 experienced firefighters took part in a series of commonly encountered SCBA activities: free search, guideline search and live firefighting tasks under room temperature (∼20°C) and extreme heat (∼180°C) conditions to assess changes in heart rate, blood pressure, mood, perceived workload and air usage. Findings demonstrate that live firefighting is associated with greater perceived exhaustion than free search or guideline exercises; however, all tasks lead to high cardiovascular demand regardless of the presence of heat. No significant impact of task upon mood and no significant differences between the perceived demands of guideline, free search and live firefighting exercises were found.
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Affiliation(s)
- Paul M Young
- a Department of Sport, Exercise and Rehabilitation , Faculty of Health & Life Sciences, Northumbria University , Newcastle upon Tyne , UK
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Selected Literature Watch. JOURNAL OF CAFFEINE RESEARCH 2014. [DOI: 10.1089/jcr.2014.1238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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