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Fan H, Meng Y, Zhu L, Fan M, Wang D, Zhao Y. A review of methods for assessment of cognitive function in high-altitude hypoxic environments. Brain Behav 2024; 14:e3418. [PMID: 38409925 PMCID: PMC10897364 DOI: 10.1002/brb3.3418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/03/2024] [Accepted: 01/13/2024] [Indexed: 02/28/2024] Open
Abstract
Hypoxic environments like those present at high altitudes may negatively affect brain function. Varying levels of hypoxia, whether acute or chronic, are previously shown to impair cognitive function in humans. Assessment and prevention of such cognitive impairment require detection of cognitive changes and impairment using specific cognitive function assessment tools. This paper summarizes the findings of previous research, outlines the methods for cognitive function assessment used at a high altitude, elaborates the need to develop standardized and systematic cognitive function assessment tools for high-altitude hypoxia environments.
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Affiliation(s)
- Haojie Fan
- Department of PsychologyZhejiang Sci‐Tech UniversityHangzhouChina
- Department of Cognitive and StressBeijing Institute of Basic Medical SciencesBeijingChina
| | - Ying Meng
- Department of PsychologyZhejiang Sci‐Tech UniversityHangzhouChina
- Department of Cognitive and StressBeijing Institute of Basic Medical SciencesBeijingChina
| | - Lingling Zhu
- Department of Cognitive and StressBeijing Institute of Basic Medical SciencesBeijingChina
| | - Ming Fan
- Department of Cognitive and StressBeijing Institute of Basic Medical SciencesBeijingChina
- School of Information Sciences & EngineeringLanzhou UniversityLanzhouChina
| | - Du‐Ming Wang
- Department of PsychologyZhejiang Sci‐Tech UniversityHangzhouChina
| | - Yong‐Qi Zhao
- Department of PsychologyZhejiang Sci‐Tech UniversityHangzhouChina
- Department of Cognitive and StressBeijing Institute of Basic Medical SciencesBeijingChina
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Li X, Ma H, Ding X, Jiang H, Zhang X. Impaired Neurological Activity in the Mental Rotation Ability of Tibetan Indigenous Residents After Chronic Exposure to High Altitude. Neuroscience 2023; 532:1-13. [PMID: 37739028 DOI: 10.1016/j.neuroscience.2023.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 09/24/2023]
Abstract
Mental rotation is a core indicator of spatial ability, and a threshold for cognitive impairment may exist at approximately 4,000 m above sea level, but the specific thresholds for the severity of hypoxia in Tibetan indigenous populations in mental rotation ability remain largely unknown. To determine whether a threshold for mental rotation impairment exists in indigenous residents, we related a mental rotation task to inter-individual differences in a range of behavioral performance and neuropsychological characteristics across 51 indigenous Tibetan highlanders and 34 matched controls at three different altitudes (sea level, 2,900 m, and 4,200 m). Analyses of reaction time showed delayed behavioral responses in the 4,200 m altitude group. Further analyses of rotation-related negativity (RRN) revealed that the RRN was significantly more negative and the differences disappeared gradually for different angles among individuals exposed to an altitude of 4,200 m. Moreover, a time-frequency analysis showed significantly enhanced alpha- and beta-band power values for the 4,200 m altitude participants after stimulus presentation. The impairment in mental rotation ability is related to hypoxia and can be attributed to the absence of sufficient cognitive resources, which demonstrates the existence of a threshold for the effects of high altitude on the brain's mental rotation ability. Taken together, our findings have important implications for exploring the altitude threshold for the influence of high-altitude exposure on brain function, as well as for guiding the development of innovative strategies to optimize the response of the organism against chronic hypoxia-induced under extreme environments.
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Affiliation(s)
- Xiaoyan Li
- School of Psychology, Northwest Normal University, Lanzhou 730000, China; Plateau Brain Science Research Center, Tibet University, Lhasa 850000, China
| | - Hailin Ma
- Plateau Brain Science Research Center, Tibet University, Lhasa 850000, China.
| | - Xiaobin Ding
- School of Psychology, Northwest Normal University, Lanzhou 730000, China.
| | - Heng Jiang
- Clinical Hospital of Chengdu Brain Science Institute, MOE Key Laboratory for Neuro-information, University of Electronic Science and Technology of China, Chengdu 610000, China
| | - Xuemei Zhang
- Shanghai Pudong Development Bank of Tibet, Lhasa 850000, China.
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Post TE, Heijn LG, Jordan J, van Gerven JMA. Sensitivity of cognitive function tests to acute hypoxia in healthy subjects: a systematic literature review. Front Physiol 2023; 14:1244279. [PMID: 37885803 PMCID: PMC10598721 DOI: 10.3389/fphys.2023.1244279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/25/2023] [Indexed: 10/28/2023] Open
Abstract
Acute exposure to hypoxia can lead to cognitive impairment. Therefore, hypoxia may become a safety concern for occupational or recreational settings at altitude. Cognitive tests are used as a tool to assess the degree to which hypoxia affects cognitive performance. However, so many different cognitive tests are used that comparing studies is challenging. This structured literature evaluation provides an overview of the different cognitive tests used to assess the effects of acute hypoxia on cognitive performance in healthy volunteers. Less frequently used similar cognitive tests were clustered and classified into domains. Subsequently, the different cognitive test clusters were compared for sensitivity to different levels of oxygen saturation. A total of 38 articles complied with the selection criteria, covering 86 different cognitive tests. The tests and clusters showed that the most consistent effects of acute hypoxia were found with the Stroop test (where 42% of studies demonstrated significant abnormalities). The most sensitive clusters were auditory/verbal memory: delayed recognition (83%); evoked potentials (60%); visual/spatial delayed recognition (50%); and sustained attention (47%). Attention tasks were not particularly sensitive to acute hypoxia (impairments in 0%-47% of studies). A significant hypoxia level-response relationship was found for the Stroop test (p = 0.001), as well as three clusters in the executive domain: inhibition (p = 0.034), reasoning/association (p = 0.019), and working memory (p = 0.024). This relationship shows a higher test sensitivity at more severe levels of hypoxia, predominantly below 80% saturation. No significant influence of barometric pressure could be identified in the limited number of studies where this was varied. This review suggests that complex and executive functions are particularly sensitive to hypoxia. Moreover, this literature evaluation provides the first step towards standardization of cognitive testing, which is crucial for a better understanding of the effects of acute hypoxia on cognition.
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Affiliation(s)
- Titiaan E. Post
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
- Centre for Human Drug Research (CHDR), Leiden, Netherlands
| | - Laurens G. Heijn
- Centre for Human Drug Research (CHDR), Leiden, Netherlands
- Leiden Academic Centre for Drug Research, Leiden, Netherlands
| | - Jens Jordan
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
- Medical Faculty, University of Cologne, Cologne, Germany
| | - Joop M. A. van Gerven
- Centre for Human Drug Research (CHDR), Leiden, Netherlands
- Leiden University Medical Center, Leiden, Netherlands
- Central Committee on Research Involving Human Subjects (CCMO), The Hague, Netherlands
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Chroboczek M, Kujach S, Łuszczyk M, Soya H, Laskowski R. Exercise-Induced Elevated BDNF Concentration Seems to Prevent Cognitive Impairment after Acute Exposure to Moderate Normobaric Hypoxia among Young Men. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3629. [PMID: 36834322 PMCID: PMC9961746 DOI: 10.3390/ijerph20043629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/12/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Memory impairment, reduced learning ability, decreased concentration, and psychomotor performance can be all signs of deleterious impact of hypoxia on cognitive functioning. In turn, physical exercise can improve performance and enhance cognitive functions. The purpose of this study was to investigate whether the potential positive effects of exercise performed under normobaric hypoxia can counteract the negative effects of hypoxia on cognitive function, and whether these changes correlate with brain-derived neurotrophic factor (BDNF) concentrations. Seventeen healthy subjects participated in a crossover study where they performed two sessions of single breathing bouts combined with moderate intensity exercise under two conditions: normoxia (NOR EX) and normobaric hypoxia (NH EX). To assess cognitive function, Stroop test was applied. There were no significant differences in any part of the Stroop interference test regardless of the conditions (NOR, NH), despite a statistical decrease in SpO2 (p < 0.0001) under normobaric hypoxic conditions. In addition, a statistical increase (p < 0.0001) in BDNF concentration was observed after both conditions. Acute exercise under normobaric hypoxia did not impair cognitive function despite a significant decrease in SpO2. Exercise in such conditions may offset the negative effects of hypoxia alone on cognitive function. This may be related to the significant increase in BDNF concentration and, as a consequence, positively affect the executive functions.
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Affiliation(s)
- Maciej Chroboczek
- Department of Physiology, Gdansk University of Physical Education and Sport, 80-336 Gdansk, Poland
| | - Sylwester Kujach
- Department of Physiology, Gdansk University of Physical Education and Sport, 80-336 Gdansk, Poland
| | - Marcin Łuszczyk
- Department of Physiology, Gdansk University of Physical Education and Sport, 80-336 Gdansk, Poland
| | - Hideaki Soya
- Sports Neuroscience Division, Advanced Research Initiative for Human High Performance, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba 305-8574, Japan
| | - Radosław Laskowski
- Department of Physiology, Gdansk University of Physical Education and Sport, 80-336 Gdansk, Poland
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Department of Sports Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba 305-8574, Japan
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Cognition and Neuropsychological Changes at Altitude-A Systematic Review of Literature. Brain Sci 2022; 12:brainsci12121736. [PMID: 36552195 PMCID: PMC9775937 DOI: 10.3390/brainsci12121736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/05/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
High-altitude (HA) exposure affects cognitive functions, but studies have found inconsistent results. The aim of this systematic review was to evaluate the effects of HA exposure on cognitive functions in healthy subjects. A structural overview of the applied neuropsychological tests was provided with a classification of superordinate cognitive domains. A literature search was performed using PubMed up to October 2021 according to PRISMA guidelines. Eligibility criteria included a healthy human cohort exposed to altitude in the field (at minimum 2440 m [8000 ft]) or in a hypoxic environment in a laboratory, and an assessment of cognitive domains. The literature search identified 52 studies (29 of these were field studies; altitude range: 2440 m-8848 m [8000-29,029 ft]). Researchers applied 112 different neuropsychological tests. Attentional capacity, concentration, and executive functions were the most frequently studied. In the laboratory, the ratio of altitude-induced impairments (64.7%) was twice as high compared to results showing no change or improved results (35.3%), but altitudes studied were similar in the chamber compared to field studies. In the field, the opposite results were found (66.4 % no change or improvements, 33.6% impairments). Since better acclimatization can be assumed in the field studies, the findings support the hypothesis that sufficient acclimatization has beneficial effects on cognitive functions at HA. However, it also becomes apparent that research in this area would benefit most if a consensus could be reached on a standardized framework of freely available neurocognitive tests.
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Liu H, Shi R, Liao R, Liu Y, Che J, Bai Z, Cheng N, Ma H. Machine Learning Based on Event-Related EEG of Sustained Attention Differentiates Adults with Chronic High-Altitude Exposure from Healthy Controls. Brain Sci 2022; 12:brainsci12121677. [PMID: 36552137 PMCID: PMC9775506 DOI: 10.3390/brainsci12121677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/20/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022] Open
Abstract
(1) Objective: The aim of this study was to examine the effect of high altitude on inhibitory control processes that underlie sustained attention in the neural correlates of EEG data, and explore whether the EEG data reflecting inhibitory control contain valuable information to classify high-altitude chronic hypoxia and plain controls. (2) Methods: 35 chronic high-altitude hypoxic adults and 32 matched controls were recruited. They were required to perform the go/no-go sustained attention task (GSAT) using event-related potentials. Three machine learning algorithms, namely a support vector machine (SVM), logistic regression (LR), and a decision tree (DT), were trained based on the related ERP components and neural oscillations to build a dichotomous classification model. (3) Results: Behaviorally, we found that the high altitude (HA) group had lower omission error rates during all observation periods than the low altitude (LA) group. Meanwhile, the ERP results showed that the HA participants had significantly shorter latency than the LAs for sustained potential (SP), indicating vigilance to response-related conflict. Meanwhile, event-related spectral perturbation (ERSP) analysis suggested that lowlander immigrants exposed to high altitudes may have compensatory activated prefrontal cortexes (PFC), as reflected by slow alpha, beta, and theta frequency-band neural oscillations. Finally, the machine learning results showed that the SVM achieved the optimal classification F1 score in the later stage of sustained attention, with an F1 score of 0.93, accuracy of 92.54%, sensitivity of 91.43%, specificity of 93.75%, and area under ROC curve (AUC) of 0.97. The results proved that SVM classification algorithms could be applied to identify chronic high-altitude hypoxia. (4) Conclusions: Compared with other methods, the SVM leads to a good overall performance that increases with the time spent on task, illustrating that the ERPs and neural oscillations may provide neuroelectrophysiological markers for identifying chronic plateau hypoxia.
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Affiliation(s)
- Haining Liu
- Psychology Department, Chengde Medical University, Chengde 067000, China
- Hebei Key Laboratory of Nerve Injury and Repair, Chengde Medical University, Chengde 067000, China
- Hebei International Research Center of Medical Engineering, Chengde Medical University, Chengde 067000, China
| | - Ruijuan Shi
- Plateau Brain Science Research Center, Tibet University/South China Normal University, Lhasa 850012, China
| | - Runchao Liao
- Department of Biomedical Engineering, Chengde Medical University, Chengde 067000, China
| | - Yanli Liu
- Department of Biomedical Engineering, Chengde Medical University, Chengde 067000, China
- Correspondence: (Y.L.); (H.M.); Tel.: +86-187-3246-7083 (Y.L.); +86-150-8905-6060 (H.M.)
| | - Jiajun Che
- Psychology Department, Chengde Medical University, Chengde 067000, China
| | - Ziyu Bai
- Psychology Department, Chengde Medical University, Chengde 067000, China
| | - Nan Cheng
- Psychology Department, Chengde Medical University, Chengde 067000, China
| | - Hailin Ma
- Hebei International Research Center of Medical Engineering, Chengde Medical University, Chengde 067000, China
- Correspondence: (Y.L.); (H.M.); Tel.: +86-187-3246-7083 (Y.L.); +86-150-8905-6060 (H.M.)
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Draper S, Singer T, Dulaney C, McDaniel J. Single Leg Cycling Offsets Reduced Muscle Oxygenation in Hypoxic Environments. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19159139. [PMID: 35897502 PMCID: PMC9331301 DOI: 10.3390/ijerph19159139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 12/04/2022]
Abstract
The intensity of large muscle mass exercise declines at altitude due to reduced oxygen delivery to active muscles. The purpose of this investigation was to determine if the greater limb blood flow during single-leg cycling prevents the reduction in tissue oxygenation observed during traditional double-leg cycling in hypoxic conditions. Ten healthy individuals performed bouts of double and single-leg cycling (4, four-minute stages at 50−80% of their peak oxygen consumption) in hypoxic (15% inspired O2) and normoxic conditions. Heart rate, mean arterial pressure, femoral blood flow, lactate, oxygenated hemoglobin, total hemoglobin, and tissue saturation index in the vastus lateralis were recorded during cycling tests. Femoral blood flow (2846 ± 912 mL/min) and oxygenated hemoglobin (−2.98 ± 3.56 au) during single-leg cycling in hypoxia were greater than double-leg cycling in hypoxia (2429 ± 835 mL/min and −6.78 ± 3.22 au respectively, p ≤ 0.01). In addition, tissue saturation index was also reduced in the double-leg hypoxic condition (60.2 ± 3.1%) compared to double-leg normoxic (66.0 ± 2.4%, p = 0.008) and single-leg hypoxic (63.3 ± 3.2, p < 0.001) conditions. These data indicate that while at altitude, use of reduced muscle mass exercise can help offset the reduction in tissue oxygenation observed during larger muscle mass activities allowing athletes to exercise at greater limb/muscle specific intensities.
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Affiliation(s)
- Shane Draper
- Department of Exercise Science and Outdoor Recreation, Utah Valley University, Orem, UT 84058, USA;
| | - Tyler Singer
- Department of Exercise Science, Fairmont State University, Fairmont, WV 26554, USA;
| | - Cody Dulaney
- Department of Fitness and Wellness Leadership, State University of New York Plattsburgh, Plattsburgh, NY 12901, USA;
| | - John McDaniel
- Department of Exercise Science, Kent State University, Kent, OH 44242, USA
- Advanced Platform Technology Center, VA Northeast Ohio Healthcare System, Cleveland, OH 44106, USA
- Correspondence:
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Sprint Interval Exercise Improves Cognitive Performance Unrelated to Postprandial Glucose Fluctuations at Different Levels of Normobaric Hypoxia. J Clin Med 2022; 11:jcm11113159. [PMID: 35683546 PMCID: PMC9181000 DOI: 10.3390/jcm11113159] [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: 03/31/2022] [Revised: 05/30/2022] [Accepted: 05/30/2022] [Indexed: 12/10/2022] Open
Abstract
Objective: The aim of our study was to examine cognition response to sprint interval exercise (SIE) against different levels of hypoxia. Research design and methods: 26 recreational active males performed SIE (20 × 6 s of all-out cycling bouts, 15 s of passive recovery) under normoxia (FIO2: 0.209), moderate hypoxia (FIO2: 0.154), and severe hypoxia (FIO2: 0.112) in a single-blinded crossover design. Cognitive function and blood glucose were assessed before and after 0, 10, 30, and 60 min of the SIE. Heart rate (HR), peripheral oxygen saturation (SpO2), and ratings of perceived exertion (RPE, the Borg 6−20-point scale) during each SIE trial were recorded before and immediately after every five cycling bouts, and after 0, 10, 30, and 60 min of the SIE. Results: All the three SIE trials had a significantly faster overall reaction time in the Stroop test at 10 min after exercise as compared to that of the baseline value (p = 0.003, ƞ2 = 0.606), and returned to normal after 60 min. The congruent RT at 10 min after SIE was significantly shorter than that of the baseline (p < 0.05, ƞ2 = 0.633), while the incongruent RT at both 10 min and 30 min were significantly shorter than that measured at baseline (p < 0.05, ƞ2 = 0.633). No significant differences in terms of accuracy were found across the three trials at any time points (p = 0.446, ƞ2 = 0.415). Blood glucose was significantly reduced at 10 min and was sustained for at least 60 min after SIE when compared to pre-exercise in all trials (p < 0.05). Conclusions: Acute SIE improved cognitive function regardless of oxygen conditions, and the sustained improvement following SIE could last for at least 10−30 min and was unaffected by the altered blood glucose level.
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Intensity-dependent acute aerobic exercise: Effect on reactive control of attentional functions in acclimatized lowlanders at high altitude. Physiol Behav 2022; 250:113785. [PMID: 35346735 DOI: 10.1016/j.physbeh.2022.113785] [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: 12/08/2021] [Revised: 03/22/2022] [Accepted: 03/22/2022] [Indexed: 11/21/2022]
Abstract
Human attentional function is sensitive to hypoxia. However, little is known about whether and how attentional function is altered after acute aerobic exercise at high altitude, especially for acclimatized lowlanders. In this study, we used the Attention Network Test (ANT) to measure alerting, orienting, and executive control functions and the Stroop Color and Word Test (SCWT) with a different proportion of incongruent trials to investigate proactive and reactive control of executive function. We randomly divided the sample of 160 Tibetan lowlanders who had lived in the highlands for more than two years into four groups. Each of three groups performed 20 min of low-, moderate-, or high-intensity acute aerobic exercise, separately, and a control group watched a 20-min documentary. The ANT and SCWT were conducted before and after exercise or watching the documentary. The results indicated that the executive control effects of the three experimental groups significantly decreased and, in the posttest, the executive control effects of the high-intensity group were lower than those of the low-intensity group. Furthermore, the accuracy of the moderate- and high-intensity groups was increased significantly in the blocks containing 25% incongruent trials of SCWT task. These results suggest that the acute aerobic exercise at high altitude will improve the reactive control of attentional functions in acclimatized lowlanders, and the intensity may play an important role in the exercise-cognition interaction at high altitude.
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Kong Z, Yu Q, Sun S, Lei OK, Tian Y, Shi Q, Nie J, Burtscher M. The Impact of Sprint Interval Exercise in Acute Severe Hypoxia on Executive Function. High Alt Med Biol 2022; 23:135-145. [PMID: 35638971 DOI: 10.1089/ham.2022.0004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Kong, Zhaowei, Qian Yu, Shengyan Sun, On Kei Lei, Yu Tian, Qingde Shi, Jinlei Nie, and Martin Burtscher. The impact of sprint interval exercise in acute severe hypoxia on executive function. High Alt Med Biol. 23: 135-145, 2022. Objective: The present study evaluated executive performance responses to sprint interval exercise in normoxia and relatively severe hypoxia. Methods: Twenty-five physically active men (age 22 ± 2 years; maximal oxygen uptake 43 ± 2 ml/[kg·min]) performed four trials including two normoxic (FIO2 = 0.209) and two normobaric hypoxic trials (FIO2 = 0.112), at rest (control) and exercise at the same time on different days. The exercise scheme consisted of 20 sets of 6-seconds all-out cycling sprint interspersed with 15-seconds recovery. The Stroop task was conducted before, 10, 30, and 60 minutes after each trial, whereas peripheral oxygen saturation (SpO2), heart rate, ratings of perceived exertion, and feelings of arousal were additionally recorded immediately after the interventions. Results: Despite the low SpO2 levels, both resting and sprint interval exercise in hypoxia had no adverse effects on executive function. Exercise elicited executive improvements in normoxia (-5.3% and -3.4% at 10 and 30 minutes after exercise) and in hypoxia (-7.8% and -4.3%), which is reflected by ameliorating incongruent reaction time and its 30-minutes sustained effects (p = 0.018). Conclusions: The findings demonstrate that sprint interval exercise caused sustained executive benefits, and exercise in relatively severe hypoxia did not impair executive performance.
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Affiliation(s)
- Zhaowei Kong
- Faculty of Education, University of Macau, Macao, China
| | - Qian Yu
- Faculty of Education, University of Macau, Macao, China
| | - Shengyan Sun
- Institute of Physical Education, Huzhou University, Huzhou, China
| | - On Kei Lei
- Faculty of Education, University of Macau, Macao, China
| | - Yu Tian
- Faculty of Education, University of Macau, Macao, China
| | - Qingde Shi
- School of Health Sciences and Sports, Macao Polytechnic Institute, Macao, China
| | - Jinlei Nie
- School of Health Sciences and Sports, Macao Polytechnic Institute, Macao, China
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
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Figueiredo PS, Sils IV, Staab JE, Fulco CS, Muza SR, Beidleman BA. Acute mountain sickness and sleep disturbances differentially influence cognition and mood during rapid ascent to 3000 and 4050 m. Physiol Rep 2022; 10:e15175. [PMID: 35133088 PMCID: PMC8822873 DOI: 10.14814/phy2.15175] [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: 10/29/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 12/04/2022] Open
Abstract
The impact of acute mountain sickness (AMS) and sleep disturbances on mood and cognition at two altitudes relevant to the working and tourist population is unknown. Twenty unacclimatized lowlanders were exposed to either 3000 m (n = 10; 526 mmHg) or 4050 m (n = 10; 460 mmHg) for 20 h in a hypobaric chamber. AMS prevalence and severity was assessed using the Environmental Symptoms Questionnaire (ESQ) and an AMS‐C score ≥ 0.7 indicated sickness. While sleeping for one night both at sea level (SL) and high altitude (HA), a wrist motion detector was used to measure awakenings (Awak, events/h) and sleep efficiency (Eff, %). If Eff was ≥85%, individuals were considered a good sleeper (Sleep+). Mood and cognition were assessed using the Automated Neuropsychological Assessment Metric and Mood Scale (ANAM‐MS). The ESQ and ANAM‐MS were administered in the morning both at SL and after 20 h at HA. AMS severity (mean ± SE; 1.82 ± 0.27 vs. 0.20 ± 0.27), AMS prevalence (90% vs. 10%), depression (0.63 ± 0.23 vs. 0.00 ± 0.24) Awak (15.6 ± 1.6 vs. 10.1 ± 1.6 events/h), and DeSHr (38.5 ± 6.3 vs. 13.3 ± 6.3 events/h) were greater (p < 0.05) and Eff was lower (69.9 ± 5.3% vs. 87.0 ± 5.3%) at 4050 m compared to 3000 m, respectively. AMS presence did not impact cognition but fatigue (2.17 ± 0.37 vs. 0.58 ± 0.39), anger (0.65 ± 0.25 vs. 0.02 ± 0.26), depression (0.63 ± 0.23 vs. 0.00 ± 0.24) and sleepiness (4.8 ± 0.4 vs. 2.7 ± 0.5) were greater (p < 0.05) in the AMS+ group. The Sleep− group, compared to the Sleep+ group, had lower (p < 0.05) working memory scores (50 ± 7 vs. 78 ± 9) assessed by the Sternberg 6‐letter memory task, and lower reaction time fatigue scores (157 ± 17 vs. 221 ± 22), assessed by the repeated reaction time test. Overall, AMS, depression, DeSHr, and Awak were increased (p < 0.05) at 4050 m compared to 3000 m. In addition, AMS presence impacted mood while poor sleep impacted cognition which may deteriorate teamwork and/or increase errors in judgement at HA.
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Affiliation(s)
- Peter S. Figueiredo
- Biophysics and Biomedical Modeling Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Ingrid V. Sils
- Thermal and Mountain Medicine Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Janet E. Staab
- Military Performance Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Charles S. Fulco
- Thermal and Mountain Medicine Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Stephen R. Muza
- Strategic Science and Development Office U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Beth A. Beidleman
- Biophysics and Biomedical Modeling Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
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Debenham MIB, Smuin JN, Grantham TDA, Ainslie PN, Dalton BH. Hypoxia and standing balance. Eur J Appl Physiol 2021; 121:993-1008. [PMID: 33484334 DOI: 10.1007/s00421-020-04581-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 12/10/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE Standing balance control is important for everyday function and often goes unnoticed until impairments appear. Presently, more than 200 million people live at altitudes > 2500 m above sea level, and many others work at or travel to these elevations. Thus, it is important to understand how hypoxia alters balance owing to implications for occupations and travelers. Herein, the influence of normobaric and hypobaric hypoxia on standing balance control is reviewed and summarized. As postural control relies on the integration of sensorimotor signals, the potential hypoxic-sensitive neurophysiological factors that contribute to balance impairments are also reviewed. Specifically, we examine how hypoxia impairs visual, vestibular, and proprioceptive cues, and their integration within subcortical or cortical areas. METHODS This systematic review included a literature search conducted via multiple databases with keywords related to postural balance, hypoxia, and altitude. Articles (n = 13) were included if they met distinct criteria. RESULTS Compared to normoxia, normobaric hypoxia worsened parameters of standing balance by 2-10% and up to 83 and 240% in hypobaric hypoxia (high-altitude and lab-based, respectively). Although balance was only disrupted during normobaric hypoxia at FIO2 < ~ 0.15, impairments consistently occurred during hypobaric hypoxia at altitudes > 1524 m (~ FIO2 < 0.18). CONCLUSION Hypoxia, especially hypobaric, impairs standing balance. The mechanisms underpinning postural decrements likely involve alterations to processing and integration of sensorimotor signals within subcortical or cortical structures involving visual, vestibular, and proprioceptive pathways and subsequent motor commands that direct postural adjustments. Future studies are required to determine the sensorimotor factors that may influence balance control in hypoxia.
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Affiliation(s)
- Mathew I B Debenham
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada
| | - Janelle N Smuin
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada
| | - Tess D A Grantham
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada
| | - Philip N Ainslie
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada
| | - Brian H Dalton
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada.
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Jung M, Zou L, Yu JJ, Ryu S, Kong Z, Yang L, Kang M, Lin J, Li H, Smith L, Loprinzi PD. Does exercise have a protective effect on cognitive function under hypoxia? A systematic review with meta-analysis. JOURNAL OF SPORT AND HEALTH SCIENCE 2020; 9:562-577. [PMID: 32325144 PMCID: PMC7749263 DOI: 10.1016/j.jshs.2020.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/08/2020] [Accepted: 02/27/2020] [Indexed: 05/02/2023]
Abstract
OBJECTIVE This study aimed to examine (1) the independent effects of hypoxia on cognitive function and (2) the effects of exercise on cognition while under hypoxia. METHODS Design: Systematic review with meta-analysis. DATA SOURCES PubMed, Scopus, Web of Science, PsychInfo, and SPORTDiscus were searched. Eligibility criteria for selecting studies: randomized controlled trials and nonrandomized controlled studies that investigated the effects of chronic or acute exercise on cognition under hypoxia were considered (Aim 2), as were studies investigating the effects of hypoxia on cognition (Aim 1). RESULTS In total, 18 studies met our inclusionary criteria for the systematic review, and 12 studies were meta-analyzed. Exposure to hypoxia impaired attentional ability (standardized mean difference (SMD) = -0.4), executive function (SMD = -0.18), and memory function (SMD = -0.26), but not information processing (SMD = 0.27). Aggregated results indicated that performing exercise under a hypoxia setting had a significant effect on cognitive improvement (SMD = 0.3, 95% confidence interval: 0.14 - 0.45, I2 = 54%, p < 0.001). Various characteristics (e.g., age, cognitive task type, exercise type, exercise intensity, training type, and hypoxia level) moderated the effects of hypoxia and exercise on cognitive function. CONCLUSION Exercise during exposure to hypoxia improves cognitive function. This association appears to be moderated by individual and exercise/hypoxia-related characteristics.
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Affiliation(s)
- Myungjin Jung
- Health and Sport Analytics Laboratory, Department of Health, Exercise Science and Recreation Management, University of Mississippi, University Park, MS 38677, USA
| | - Liye Zou
- Exercise and Mental Health Laboratory, School of Psychology, Shenzhen University, Shenzhen 518060, China.
| | - Jane Jie Yu
- Department of Sports Science and Physical Education, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong 999077, China
| | - Seungho Ryu
- Health and Sport Analytics Laboratory, Department of Health, Exercise Science and Recreation Management, University of Mississippi, University Park, MS 38677, USA
| | - Zhaowei Kong
- Faculty of Education, University of Macau, Taipa, Macau 999078, China
| | - Lin Yang
- Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, AB T2S 3C3, Canada; Departments of Oncology and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Minsoo Kang
- Health and Sport Analytics Laboratory, Department of Health, Exercise Science and Recreation Management, University of Mississippi, University Park, MS 38677, USA
| | - Jingyuan Lin
- Exercise and Mental Health Laboratory, School of Psychology, Shenzhen University, Shenzhen 518060, China
| | - Hong Li
- Exercise and Mental Health Laboratory, School of Psychology, Shenzhen University, Shenzhen 518060, China
| | - Lee Smith
- The Cambridge Centre for Sport and Exercise Sciences, Anglia Ruskin University, Cambridge, CB1 1PT, UK
| | - Paul D Loprinzi
- Exercise and Memory Laboratory, Department of Health, Exercise Science and Recreation Management, University of Mississippi, Oxford, MS 38677, USA
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Walsh JJ, Drouin PJ, King TJ, D'Urzo KA, Tschakovsky ME, Cheung SS, Day TA. Acute aerobic exercise impairs aspects of cognitive function at high altitude. Physiol Behav 2020; 223:112979. [PMID: 32479806 DOI: 10.1016/j.physbeh.2020.112979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 11/28/2019] [Accepted: 05/20/2020] [Indexed: 12/24/2022]
Abstract
Hypoxia-mediated cognitive dysfunction can be transiently mitigated by exercise in a laboratory-based setting. Whether this effect holds true in the context of high altitude hypoxia has not been determined. We investigated the effect of acute aerobic exercise on cognitive function (CF) at low (1400m) and high altitude (4240m). Fifteen volunteers (24.1±3.5yrs; 9 females) exercised for 20-min at 40-60% of their heart rate reserve at low and high altitude. CF was assessed before and 10-min after exercise using a tablet-based battery of executive function tests. A sea-level control group (n=13; 24.2±2.4 years; 9 females) performed time-matched CF tests to assess the contribution of a learning effects due to repeated testing. Measures of resting CF were unaffected by ascent to high altitude. Following high altitude exercise, performance significantly worsened on the digit symbol substitution task - a test of processing speed, working memory, and visuospatial attention (z=0.01 vs. -0.59, p=0.02, η2=0.35). No effect was found on other measures of CF following exercise. There was no association between changes in peripheral oxygen saturation and changes in CF following high altitude exercise (r=0.22, p=0.44), but higher hemoglobin concentration at high altitude was associated with a decline in CF following exercise at high altitude (r=-0.65, p=0.02). Acute aerobic exercise performed at high altitude impairs some aspects of CF, whereas other CF tests remain unchanged. The strong ecological validity of this study warrants attention and follow-up investigations are needed to better characterize selective impairment of CF with high altitude exercise.
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Affiliation(s)
- Jeremy J Walsh
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada; School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada.
| | - Patrick J Drouin
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada
| | - Trevor J King
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada; Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Katrina A D'Urzo
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada
| | | | - Stephen S Cheung
- Department of Kinesiology, Brock University, St. Catherines, ON, Canada
| | - Trevor A Day
- Department of Biology, Mount Royal University, Calgary, AB, Canada
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Carballo-Fazanes A, Barcala-Furelos R, Eiroa-Bermúdez J, Fernández-Méndez M, Abelairas-Gómez C, Martínez-Isasi S, Murciano M, Fernández-Méndez F, Rodríguez-Núñez A. Physiological demands of quality cardiopulmonary resuscitation performed at simulated 3250 meters high. Am J Emerg Med 2019; 38:2580-2585. [PMID: 31911060 DOI: 10.1016/j.ajem.2019.12.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 01/03/2023] Open
Abstract
AIM To analyse the effect of oxygen fraction reduction (O2 14%, equivalent to 3250 m) on Q-CPR and rescuers' physiological demands. METHODOLOGY A quasi-experimental study was carried out in a sample of 9 Q-CPR proficient health care professionals. Participants, in teams of 2 people, performed 10 min CPR on a Laerdal ResusciAnne mannequin (30:2 compression/ventilation ratio and alternating roles between rescuers every 2 min) in two simulated settings: T21-CPR at sea level (FiO2 of 21%) and T14 - CPR at 3250 m altitude (FiO2 of 14%). Effort self-perception was rated from 0 (no effort) to 10 (maximum demand) points. RESULTS Quality of chest compressions was good and similar in both conditions (T21 vs T14). However, the percentage of ventilations with adequate tidal volume was lower in altitude than at sea level conditions (35.9 ± 25.2% vs. 54.7 ± 23.2%, p = 0.035). The subjective perception of effort was significantly higher at simulated altitude (5 ± 2) than at sea level (3 ± 2) (p = 0.038). Maximum heart rate during the tests was similar in both conditions; however, mean oxygen saturation was significantly lower in altitude conditions (90.5 ± 2.5% vs. 99.3 ± 0.5%, p < 0.001). CONCLUSION Although performing CPR under simulated hypoxic altitude conditions significantly increases the physiological demands and subjective feeling of tiredness compared to sea level CPR, trained rescuers are able to deliver good Q-CPR in such conditions, at least in the first 10 min of resuscitation.
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Affiliation(s)
- Aida Carballo-Fazanes
- CLINURSID Research Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Santiago de Compostela's Health Research Institute (IDIS), Santiago de Compostela, Spain
| | - Roberto Barcala-Furelos
- CLINURSID Research Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Santiago de Compostela's Health Research Institute (IDIS), Santiago de Compostela, Spain; Faculty of Education and Sport Sciences, REMOSS Network Research, Universidade de Vigo, Pontevedra, Spain
| | | | - María Fernández-Méndez
- CLINURSID Research Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; School of Nursing, REMOSS Network Research, Universidade de Vigo, Pontevedra, Spain
| | - Cristian Abelairas-Gómez
- CLINURSID Research Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Santiago de Compostela's Health Research Institute (IDIS), Santiago de Compostela, Spain; Faculty of Education and Sport Sciences, REMOSS Network Research, Universidade de Vigo, Pontevedra, Spain; Faculty of Education Sciences, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.
| | - Santiago Martínez-Isasi
- CLINURSID Research Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Faculty of Nursing, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Manuel Murciano
- Pediatric Department, Hospital Universitario Policlinico Humberto I, Universidad de Roma "Sapienza", Roma, Italy
| | - Felipe Fernández-Méndez
- CLINURSID Research Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; School of Nursing, REMOSS Network Research, Universidade de Vigo, Pontevedra, Spain
| | - Antonio Rodríguez-Núñez
- CLINURSID Research Group, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Santiago de Compostela's Health Research Institute (IDIS), Santiago de Compostela, Spain; Faculty of Nursing, Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Pediatric Intensive Care Unit, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain
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16
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Ando S, Komiyama T, Sudo M, Higaki Y, Ishida K, Costello JT, Katayama K. The interactive effects of acute exercise and hypoxia on cognitive performance: A narrative review. Scand J Med Sci Sports 2019; 30:384-398. [PMID: 31605635 DOI: 10.1111/sms.13573] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 09/09/2019] [Accepted: 10/04/2019] [Indexed: 12/13/2022]
Abstract
Acute moderate intensity exercise has been shown to improve cognitive performance. In contrast, hypoxia is believed to impair cognitive performance. The detrimental effects of hypoxia on cognitive performance are primarily dependent on the severity and duration of exposure. In this review, we describe how acute exercise under hypoxia alters cognitive performance, and propose that the combined effects of acute exercise and hypoxia on cognitive performance are mainly determined by interaction among exercise intensity and duration, the severity of hypoxia, and duration of exposure to hypoxia. We discuss the physiological mechanism(s) of the interaction and suggest that alterations in neurotransmitter function, cerebral blood flow, and possibly cerebral metabolism are the primary candidates that determine cognitive performance when acute exercise is combined with hypoxia. Furthermore, acclimatization appears to counteract impaired cognitive performance during prolonged exposure to hypoxia although the precise physiological mechanism(s) responsible for this amelioration remain to be elucidated. This review has implications for sporting, occupational, and recreational activities at terrestrial high altitude where cognitive performance is essential. Further studies are required to understand physiological mechanisms that determine cognitive performance when acute exercise is performed in hypoxia.
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Affiliation(s)
- Soichi Ando
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Takaaki Komiyama
- Center for Education in Liberal Arts and Sciences, Osaka University, Osaka, Japan
| | - Mizuki Sudo
- Meiji Yasuda Life Foundation of Health and Welfare, Tokyo, Japan
| | - Yasuki Higaki
- Faculty of Sports Science, Fukuoka University, Fukuoka, Japan
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan
| | - Joseph T Costello
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, UK
| | - Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan
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Investigating Effects of Cold Water Hand Immersion on Selective Attention in Normobaric Hypoxia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16162859. [PMID: 31405091 PMCID: PMC6720274 DOI: 10.3390/ijerph16162859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 11/16/2022]
Abstract
This study investigated the effect of cold-water hand immersion on selective attention as measured by the Stroop Color Word Test in nomorbaric normoxia and hypoxia. Ten healthy men rested for 60 min, after which they immersed their non-dominant hand into 5 °C water for 15 min. The interference score of the Stroop Color Word Test and thermal sensation were measured at baseline in the final 5 min of resting and in the final 5 min of cold water hand immersion. The interference score was not influenced by hypoxia but was found to be significantly improved compared to resting in both conditions during cold water hand immersion. Selective attention improved during 15 min of cold-water hand immersion, with increased thermal sensations rated as “very cool” of the immersed arm. Cold-water hand immersion may be helpful in improving cognitive function in normoxia and normobaric hypoxia.
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Severe Hypoxia Does Not Offset the Benefits of Exercise on Cognitive Function in Sedentary Young Women. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16061003. [PMID: 30897697 PMCID: PMC6466299 DOI: 10.3390/ijerph16061003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/13/2019] [Accepted: 03/18/2019] [Indexed: 12/15/2022]
Abstract
Purpose: To examine the effect of acute moderate-intensity continuous exercise performed under normobaric severe hypoxia on cognition, compared to sea-level normoxia. Methods: Thirty healthy inactive women randomly performed two experimental trials separated by at least three days but at approximately the same time of day. Executive functions were measured during the follicular stage via an interference control task before (rest) and during exercise with 45% peak power output under normobaric normoxia (PIO₂ = 150 mmHg, FIO₂ = 0.21), and (2) hypoxia (PIO₂ = 87 mmHg, FIO₂ = 0.12, simulated at an altitude of 4000 m). Reaction time (RT), accuracy rate (AC), heart rate, ratings of perceived exertion, and peripheral oxygen saturation (SpO₂) were collected before and during exercise. Results: RT (p < 0.05, η²p = 0.203) decreased during moderate exercise when compared at rest, while a short bout of severe hypoxia improved RT (p < 0.05, η²p = 0.134). Exercise and hypoxia had no effects on AC (p > 0.05). No significant associations were found between the changes of RT and SpO₂ under the conditions of normoxia and hypoxia (p > 0.05). Conclusions: At the same phase of the menstrual cycle, a short bout of severe hypoxia simulated at 4000 m altitude caused no impairment at rest. RT during moderate exercise ameliorated in normoxia and severe hypoxia, suggesting that both exercise and short-term severe hypoxia have benefits on cognitive function in sedentary young women.
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Sun S, Loprinzi PD, Guan H, Zou L, Kong Z, Hu Y, Shi Q, Nie J. The Effects of High-Intensity Interval Exercise and Hypoxia on Cognition in Sedentary Young Adults. ACTA ACUST UNITED AC 2019; 55:medicina55020043. [PMID: 30744172 PMCID: PMC6409841 DOI: 10.3390/medicina55020043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 01/05/2023]
Abstract
Background and Objectives: Limited research has evaluated the effects of acute exercise on cognition under different conditions of inspired oxygenation. Thus, the purpose of this study was to examine the effects of high-intensity interval exercise (HIE) under normoxia (inspired fraction of oxygen (FIO2): 0.209) and moderate hypoxia (FIO2: 0.154) on cognitive function. Design: A single-blinded cross-over design was used to observe the main effects of exercise and oxygen level, and interaction effects on cognitive task performance. Methods: Twenty inactive adults (10 males and 10 females, 19–27 years old) performed a cognitive task (i.e., the Go/No-Go task) before and immediately after an acute bout of HIE under normoxic and hypoxic conditions. The HIE comprised 10 repetitions of 6 s high-intensity cycling against 7.5% body weight interspersed with 30 s passive recovery. Heart rate, peripheral oxygen saturation (SpO2) and rating of perceived exertion were monitored. Results: The acute bout of HIE did not affect the reaction time (p = 0.204, η2 = 0.083) but the accuracy rate decreased significantly after HIE under both normoxic and hypoxic conditions (p = 0.001, η2 = 0.467). Moreover, moderate hypoxia had no influence either on reaction time (p = 0.782, η2 = 0.004) or response accuracy (p = 0.972, η2 < 0.001). Conclusions: These results indicate that an acute session of HIE may impair response accuracy immediately post-HIE, without sacrificing reaction time. Meanwhile moderate hypoxia was found to have no adverse effect on cognitive function in inactive young adults, at least in the present study.
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Affiliation(s)
- Shengyan Sun
- Faculty of Education, University of Macau, Macao, China.
- Department of Physical Education, Huzhou University, Huzhou 313000, China.
| | - Paul D Loprinzi
- Department of Health, Exercise Science and Recreation Management, School of Applied Sciences, The University of Mississippi, Oxford, MS 38677, USA.
| | - Hongwei Guan
- Department of Health Promotion and Physical Education, School of Health Sciences and Human Performance, Ithaca College, Ithaca, NY 14850, USA.
| | - Liye Zou
- Lifestyle (Mind-Body Movement) Research Center, College of Sports Science, Shenzhen University, Shenzhen 518060, China.
| | - Zhaowei Kong
- Faculty of Education, University of Macau, Macao, China.
| | - Yang Hu
- Sports Science Research Center, Beijing Sport University, Beijing 100084, China.
| | - Qingde Shi
- School of Physical Education and Sports, Macao Polytechnic Institute, Macao, China.
| | - Jinlei Nie
- School of Physical Education and Sports, Macao Polytechnic Institute, Macao, China.
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20
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The influence of hypoxia and prolonged exercise on attentional performance at high and extreme altitudes: A pilot study. PLoS One 2018; 13:e0205285. [PMID: 30281651 PMCID: PMC6169942 DOI: 10.1371/journal.pone.0205285] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/21/2018] [Indexed: 12/13/2022] Open
Abstract
Introduction Exposure to hypoxic conditions is reported to impair cognitive performance. Further, moderate physical exercise improves cognitive function, but little is known about the influence of exercise on cognitive function in hypoxia. Therefore, the current study aimed to examine the influence of hypoxia (HYP) and prolonged exercise (EX) on attentional performance. Methods A total of 80 participants (female: n = 29; male: n = 51) were assigned to four groups: HYP + EX (n = 15), HYP (n = 25), EX (n = 21) and normoxia (NOR) (n = 21). The Frankfurt Attention Inventory—2 (FAIR-2) was performed at four testing points (day 1, 14, 16 and 18) to assess attentional performance. All groups completed a pretest (D1) and a follow-up test (D18). In HYP + EX conditions, the cognitive task was performed in a hypoxic state after prolonged exercise (D14: 3950 m, D16: 5739 m) during a mountain climb on Mt. Kilimanjaro. Participants in HYP were tested under intermittent hypoxia at rest in a hypoxic chamber (D14: 3500 m, D16: 5800 m), and those in EX were tested under normoxia after prolonged exercise during a 7-day backcountry ski hiking tour. NOR was a control group, and participants completed all tests under normoxia and at rest. Results Hypoxia impaired the attentional functions performance value (PV) and continuity value (CV) for the HYP + EX (p = 0.000) and HYP (L: p = 0.025; K: p = 0.043) groups at 5739 m and 5800 m, respectively, but not the function quality value (QV). In contrast, the EX group did not exhibit changes in attentional function. Conclusion The current results suggest that attentional performance is impaired during extreme normobaric and hypobaric hypoxic exposure. We further conclude that greater cognitive impairment under hypobaric hypoxia during a mountain climb compared with normobaric hypoxia at rest is not caused by prolonged exercise, but may be influenced by other factors (e.g. low temperatures, dehydration, or sleep deprivation) that remain to be verified.
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Abstract
Acute exercise has been demonstrated to improve cognitive function. In contrast, severe hypoxia can impair cognitive function. Hence, cognitive function during exercise under severe hypoxia may be determined by the balance between the beneficial effects of exercise and the detrimental effects of severe hypoxia. However, the physiological factors that determine cognitive function during exercise under hypoxia remain unclear. Here, we examined the combined effects of acute exercise and severe hypoxia on cognitive function and identified physiological factors that determine cognitive function during exercise under severe hypoxia. The participants completed cognitive tasks at rest and during moderate exercise under either normoxic or severe hypoxic conditions. Peripheral oxygen saturation, cerebral oxygenation, and middle cerebral artery velocity were continuously monitored. Cerebral oxygen delivery was calculated as the product of estimated arterial oxygen content and cerebral blood flow. On average, cognitive performance improved during exercise under both normoxia and hypoxia, without sacrificing accuracy. However, under hypoxia, cognitive improvements were attenuated for individuals exhibiting a greater decrease in peripheral oxygen saturation. Cognitive performance was not associated with other physiological parameters. Taken together, the present results suggest that arterial desaturation attenuates cognitive improvements during exercise under hypoxia.
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