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Ogoh S. Relationship between cognitive function and regulation of cerebral blood flow. J Physiol Sci 2017; 67:345-351. [PMID: 28155036 PMCID: PMC10717011 DOI: 10.1007/s12576-017-0525-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 01/23/2017] [Indexed: 12/11/2022]
Abstract
Ageing is the primary risk factor for cognitive deterioration. Given that the cerebral blood flow (CBF) or regulation of cerebral circulation is attenuated in the elderly, it could be expected that ageing-induced cognitive deterioration may be affected by a decrease in CBF as a result of brain ischemia and energy depletion. CBF regulation associated with cerebral metabolism thus likely plays an important role in the preservation of cognitive function. However, in some specific conditions (e.g. during exercise), change in CBF does not synchronize with that of cerebral metabolism. Our recent study demonstrated that cognitive function was more strongly affected by changes in cerebral metabolism than by changes in CBF during exercise. Therefore, it remains unclear how an alteration in CBF or its regulation affects cognitive function. In this review, I summarize current knowledge on previous investigations providing the possibility of an interaction between regulation of CBF or cerebral metabolism and cognitive function.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-Shi, Saitama, 350-8585, Japan.
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Effect of acute hypoxia on cognition: A systematic review and meta-regression analysis. Neurosci Biobehav Rev 2017; 74:225-232. [PMID: 28111267 DOI: 10.1016/j.neubiorev.2017.01.019] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/12/2017] [Accepted: 01/16/2017] [Indexed: 12/20/2022]
Abstract
A systematic meta-regression analysis of the effects of acute hypoxia on the performance of central executive and non-executive tasks, and the effects of the moderating variables, arterial partial pressure of oxygen (PaO2) and hypobaric versus normobaric hypoxia, was undertaken. Studies were included if they were performed on healthy humans; within-subject design was used; data were reported giving the PaO2 or that allowed the PaO2 to be estimated (e.g. arterial oxygen saturation and/or altitude); and the duration of being in a hypoxic state prior to cognitive testing was ≤6days. Twenty-two experiments met the criteria for inclusion and demonstrated a moderate, negative mean effect size (g=-0.49, 95% CI -0.64 to -0.34, p<0.001). There were no significant differences between central executive and non-executive, perception/attention and short-term memory, tasks. Low (35-60mmHg) PaO2 was the key predictor of cognitive performance (R2=0.45, p<0.001) and this was independent of whether the exposure was in hypobaric hypoxic or normobaric hypoxic conditions.
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Horiuchi M, Handa Y, Abe D, Fukuoka Y. Walking economy at simulated high altitude in human healthy young male lowlanders. Biol Open 2016; 5:1408-1414. [PMID: 27744292 PMCID: PMC5087691 DOI: 10.1242/bio.019810] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We measured oxygen consumption during walking per unit distance (Cw) values for 12 human healthy young males at six speeds from 0.667 to 1.639 m s−1 (four min per stage) on a level gradient under normobaric normoxia, moderate hypoxia (15% O2), and severe hypoxia (11% O2). Muscle deoxygenation (HHb) was measured at the vastus lateralis muscle using near-infrared spectroscopy. Economical speed which can minimize the Cw in each individual was calculated from a U-shaped relationship. We found a significantly slower economical speed (ES) under severe hypoxia [1.237 (0.056) m s−1; mean (s.d.)] compared to normoxia [1.334 (0.070) m s−1] and moderate hypoxia [1.314 (0.070) m s−1, P<0.05 respectively] with no differences between normoxia and moderate hypoxia (P>0.05). HHb gradually increased with increasing speed under severe hypoxia, while it did not increase under normoxia and moderate hypoxia. Changes in HHb between standing baseline and the final minute at faster gait speeds were significantly related to individual ES (r=0.393 at 1.250 m s−1, r=0.376 at 1.444 m s−1, and r=0.409 at 1.639 m s−1, P<0.05, respectively). These results suggested that acute severe hypoxia slowed ES by ∼8%, but moderate hypoxia left ES unchanged. Summary: Acute severe hypoxia slowed the economical speed (ES) which can minimize energy cost of walking. Muscle O2 extraction may be one of the determining factors of an individual's ES.
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Affiliation(s)
- Masahiro Horiuchi
- Division of Human Environmental Science, Mt. Fuji Research Institute, Kami-yoshida 5597-1, Fuji-yoshida-city, Yamanashi 4030005, Japan
| | - Yoko Handa
- Division of Human Environmental Science, Mt. Fuji Research Institute, Kami-yoshida 5597-1, Fuji-yoshida-city, Yamanashi 4030005, Japan
| | - Daijiro Abe
- Center for Health and Sports Science, Kyushu Sangyo University, Matsukadai 2-3-1, Higashi-ku, Fukuoka-city, Fukuoka 8138503, Japan
| | - Yoshiyuki Fukuoka
- Faculty of Health and Sports Science, Doshisha University, Tatara 1-3, Kyotanabe, Kyoto 6100394, Japan
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Dobashi S, Horiuchi M, Endo J, Kiuchi M, Koyama K. Cognitive Function and Cerebral Oxygenation During Prolonged Exercise Under Hypoxia in Healthy Young Males. High Alt Med Biol 2016; 17:214-221. [PMID: 27584683 DOI: 10.1089/ham.2016.0036] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Dobashi, Shohei, Masahiro Horiuchi, Junko Endo, Masataka Kiuchi, and Katsuhiro Koyama. Cognitive function and cerebral oxygenation during prolonged exercise under hypoxia in healthy young males. High Alt Med Biol. 17:214-221, 2016.-The present study examined the effect of prolonged hypoxic exercise on cognitive function. Eight healthy male volunteers were required to complete exercise trials (four 30-minute cycling sessions with a 15-minute rest interval) at an intensity corresponding to 50% of their altitude-adjusted peak oxygen uptake under two different conditions: normoxia (room air at 400 m) and hypoxia (fraction of inspired oxygen: 0.141). Cognitive function was evaluated before, during, and 60 minutes after completion of the exercise trial. The color-word Stroop task (CWST) was used to assess cognitive function, with regard to the number of achievements, accuracy rate, and the number of correct responses made within 60 seconds. Cerebral oxygenation was monitored throughout the experimental period using near-infrared spectroscopy. The accuracy rate did not significantly differ between the two trials. A significant reduction in the number of correct responses during simple CWST tasks was detected in the hypoxic condition 60 minutes after exercise (p < 0.05), wherein a significant correlation was identified between reduced task performance on simple CWST and cerebral oxygenation (p < 0.01). These results demonstrate that prolonged exercise under hypoxic conditions induces a reduction in cerebral oxygenation partly associated with impairment of cognitive function.
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Affiliation(s)
- Shohei Dobashi
- 1 Integrated Graduate School Department of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi , Kofu, Japan
| | - Masahiro Horiuchi
- 2 Division of Human Environmental Science, Mt. Fuji Research Institute , Fujiyoshida, Japan
| | - Junko Endo
- 2 Division of Human Environmental Science, Mt. Fuji Research Institute , Fujiyoshida, Japan
| | - Masataka Kiuchi
- 3 Graduate School Department of Education, University of Yamanashi , Kofu, Japan
| | - Katsuhiro Koyama
- 4 Graduate School Department of Interdisciplinary Research, University of Yamanashi , Kofu, Japan
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Lefferts WK, Babcock MC, Tiss MJ, Ives SJ, White CN, Brutsaert TD, Heffernan KS. Effect of hypoxia on cerebrovascular and cognitive function during moderate intensity exercise. Physiol Behav 2016; 165:108-18. [PMID: 27402021 DOI: 10.1016/j.physbeh.2016.07.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 07/03/2016] [Accepted: 07/07/2016] [Indexed: 12/25/2022]
Abstract
Exercise in hypoxia places added demands on the brain and cerebrovasculature that can impact cognitive function. The purpose of this study was to investigate the effect of acute hypoxia on cerebrovascular hemodynamics, markers of neuro-steroidal modulation and brain-blood barrier (BBB) integrity, and cognition during exercise. Thirty healthy participants (21±4yrs., BMI 24.0±2.6kg∙m(-2); 15 men) were randomized to both a≈2.5h normoxic (FiO2 20.0%) and hypoxic (FiO2 12.5%) condition on two separate days. After 1.25h, participants underwent 10min of exercise-alone (cycling at 55% HRmax) and 15min of exercise+cognitive testing. Prefrontal cortex (PFC) tissue oxygenation and middle cerebral artery (MCA) mean blood velocity (MnV) were measured using near-infrared spectroscopy and transcranial Doppler respectively at rest, during exercise-alone, and during exercise+cognitive testing. Salivary levels of dehydroepiandosterone [DHEA], DHEA-sulfate [DHEAS]) and neuron specific enolase (NSE) were measured pre and post exercise. Cognition was assessed using standard metrics of accuracy and reaction time (RT), and advanced metrics from drift-diffusion modeling across memory recognition, N-Back and Flanker tasks. MCA MnV increased from rest to exercise (p<0.01) and was unchanged with addition of cognitive testing during exercise in both normoxia and hypoxia. PFC oxygenation increased during exercise (p<0.05) and was further increased with addition of cognitive challenge in normoxia but decreased during exercise in hypoxia (p<0.05) with further reductions occurring with addition of cognitive tasks (p<0.05). DHEA and NSE increased and decreased post-exercise, respectively, in both normoxia and hypoxia (p<0.01). Accuracy on cognitive tasks was similar in normoxia compared to hypoxia, while RT was slower in hypoxia vs normoxia across memory recognition (p<0.01) and Flanker tasks (p=0.04). Drift-diffusion modeling suggested changes in memory RT were due to increases in caution (p<0.01). Overall cognitive performance is maintained during exercise in hypoxia concomitant with slower RT in select cognitive tasks and reduced oxygenation in the PFC. These changes were accompanied by slight increases in neuro-steroidal modulation but appear independent of changes in NSE, a biomarker of BBB integrity. Maintained accuracy and select increases in RT during hypoxic exercise may be related behavioral changes in caution.
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Fan JL, Kayser B. Fatigue and Exhaustion in Hypoxia: The Role of Cerebral Oxygenation. High Alt Med Biol 2016; 17:72-84. [DOI: 10.1089/ham.2016.0034] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Jui-Lin Fan
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
- Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand
| | - Bengt Kayser
- Institute of Sports Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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Tsukamoto H, Suga T, Takenaka S, Tanaka D, Takeuchi T, Hamaoka T, Isaka T, Ogoh S, Hashimoto T. Repeated high-intensity interval exercise shortens the positive effect on executive function during post-exercise recovery in healthy young males. Physiol Behav 2016; 160:26-34. [PMID: 27060507 DOI: 10.1016/j.physbeh.2016.03.029] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 03/25/2016] [Accepted: 03/25/2016] [Indexed: 12/25/2022]
Abstract
A single bout of aerobic exercise improves executive function (EF), but only for a short period. Compared with a single bout of aerobic exercise, we recently found that high-intensity interval exercise (HIIE) could maintain a longer improvement in EF. However, the mechanism underlying the effect of different exercise modes on the modifications of EF remains unclear. The purpose of the current investigation was to test our hypothesis that the amount of exercise-induced lactate production and its accumulation affects human brain function during and after exercise, thereby affecting post-exercise EF. Ten healthy male subjects performed cycle ergometer exercise. The HIIE protocol consisted of four 4-min bouts at 90% peak VO2 with a 3-min active recovery period at 60% peak VO2. The amount of lactate produced during exercise was manipulated by repeating the HIIE twice with a resting period of 60min between the 1st HIIE and 2nd HIIE. To evaluate EF, a color-word Stroop task was performed, and reverse-Stroop interference scores were obtained. EF immediately after the 1st HIIE was significantly improved compared to that before exercise, and the improved EF was sustained during 40min of the post-exercise recovery. However, for the 2nd HIIE, the improved EF was sustained for only 10min of the post-exercise recovery period, despite the performance of the same exercise. In addition, during and following HIIE, the glucose and lactate accumulation induced by the 2nd HIIE was significantly lower than that induced by the 1st HIIE. Furthermore, there was an inverse relationship between lactate and EF by plotting the changes in lactate levels against changes in EF from pre-exercise during the late phase of post-exercise recovery. These findings suggested the possibility that repeated bouts of HIIE, which decreases lactate accumulation, may dampen the positive effect of exercise on EF during the post-exercise recovery.
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Affiliation(s)
- Hayato Tsukamoto
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan; Research Fellow of the Japan Society for the Promotion of Science, Tokyo, Japan
| | - Tadashi Suga
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Saki Takenaka
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Daichi Tanaka
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Tatsuya Takeuchi
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Takafumi Hamaoka
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan; School of Medicine, Tokyo Medical University, Tokyo, Japan
| | - Tadao Isaka
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Shigehiko Ogoh
- Graduate School of Engineering, Toyo University, Saitama, Japan
| | - Takeshi Hashimoto
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
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Komiyama T, Sudo M, Okuda N, Yasuno T, Kiyonaga A, Tanaka H, Higaki Y, Ando S. Cognitive function at rest and during exercise following breakfast omission. Physiol Behav 2016; 157:178-84. [PMID: 26876456 DOI: 10.1016/j.physbeh.2016.02.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 02/03/2016] [Accepted: 02/09/2016] [Indexed: 11/30/2022]
Abstract
It has been suggested that breakfast omission, as opposed to breakfast consumption, has the detrimental effects on cognitive function. However, the effects of acute exercise following breakfast omission on cognitive function are poorly understood, particularly during exercise. The purpose of this study was to examine the interactive effects of breakfast and exercise on cognitive function. Ten participants completed cognitive tasks at rest and during exercise in the breakfast consumption or omission conditions. Blood glucose concentration was measured immediately after each cognitive task. We used cognitive tasks to assess working memory [Spatial Delayed Response (DR) task] and executive function [Go/No-Go (GNG) task]. The participants cycled ergometer for 30 min while keeping their heart rate at 140 beats·min(-1). Accuracy of the GNG task was lower at rest in the breakfast omission condition than that in the breakfast consumption condition (Go trial: P=0.012; No-Go trial: P=0.028). However, exercise improved accuracy of the Go trial in the breakfast omission condition (P=0.013). Reaction time in the Go trial decreased during exercise relative to rest in both conditions (P=0.002), and the degree of decreases in reaction time was not different between conditions (P=0.448). Exercise and breakfast did not affect the accuracy of the Spatial DR task. The present results indicate that breakfast omission impairs executive function, but acute exercise improved executive function even after breakfast omission. It appears that beneficial effects of acute exercise on cognitive function are intact following breakfast omission.
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Affiliation(s)
- Takaaki Komiyama
- Graduate School of Sports and Health Science, Fukuoka University, Japan
| | - Mizuki Sudo
- Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Japan; Fukuoka University Institute for Physical Activity, Japan
| | - Naoki Okuda
- Faculty of Sports and Health Science, Fukuoka University, Japan
| | - Tetsuhiko Yasuno
- Department of Internal Medicine, Fukuoka University School of Medicine, Japan
| | - Akira Kiyonaga
- Fukuoka University Institute for Physical Activity, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan
| | - Hiroaki Tanaka
- Fukuoka University Institute for Physical Activity, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan
| | - Yasuki Higaki
- Fukuoka University Institute for Physical Activity, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan
| | - Soichi Ando
- Faculty of Sports and Health Science, Fukuoka University, Japan; Graduate School of Informatics and Engineering, The University of Electro-communications, Japan.
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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: 147] [Impact Index Per Article: 18.4] [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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Reduction in Cerebral Oxygenation After Prolonged Exercise in Hypoxia is Related to Changes in Blood Pressure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 876:95-100. [PMID: 26782200 DOI: 10.1007/978-1-4939-3023-4_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We investigated the relation between blood pressure and cerebral oxygenation (COX) immediately after exercise in ten healthy males. Subjects completed an exercise and recovery protocol while breathing either 21% (normoxia) or 14.1% (hypoxia) O2 in a randomized order. Each exercise session included four sets of cycling (30 min/set, 15 min rest) at 50% of altitude-adjusted peak oxygen uptake, followed by 60 min of recovery. After exercise, mean arterial pressure (MAP; 87±1 vs. 84±1 mmHg, average values across the recovery period) and COX (68±1% vs. 58±1%) were lower in hypoxia compared to normoxia (P<0.001). Changes in MAP and COX were correlated during the recovery period in hypoxia (r=0.568, P<0.001) but not during normoxia (r=0.028, not significant). These results demonstrate that reductions in blood pressure following exercise in hypoxia are (1) more pronounced than in normoxia, and (2) associated with reductions in COX. Together, these results suggest an impairment in cerebral autoregulation as COX followed changes in MAP more passively in hypoxia than in normoxia. These findings could help explain the increased risk for postexercise syncope at high altitude.
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Seo Y, Burns K, Fennell C, Kim JH, Gunstad J, Glickman E, McDaniel J. The Influence of Exercise on Cognitive Performance in Normobaric Hypoxia. High Alt Med Biol 2015. [PMID: 26214045 DOI: 10.1089/ham.2015.0027] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Although previous reports indicate that exercise improves cognitive function in normoxia, the influence of exercise on cognitive function in hypoxia is unknown. The purpose of this study was to determine if the impaired cognitive function in hypoxia can be restored by low to moderate intensity exercise. Sixteen young healthy men completed the ANAM versions of the Go/No-Go task (GNT) and Running Memory Continuous Performance Task (RMCPT) in normoxia to serve as baseline (B-Norm) (21% O2). Following 60 minutes of exposure to normobaric hypoxia (B-Hypo) (12.5% O2), these tests were repeated at rest and during cycling exercise at 40% and 60% of adjusted Vo2max. At B-Hypo, the % correct (p≤0.001) and throughput score (p≤0.001) in RMCPT were significantly impaired compared to B-Norm. During exercise at 40% (p=0.023) and 60% (p=0.006) of adjusted Vo2max, the throughput score in RMCPT improved compared to B-Hypo, and there was no significant difference in throughput score between the two exercise intensities. Mean reaction time also improved at both exercise intensities compared to B-Hypo (p≤0.028). Both peripheral oxygen saturation (Spo2) and regional cerebral oxygen saturation (rSo2) significantly decreased during B-Hypo (p≤0.001) and further decreased at 40% (p≤0.05) and 60% (p≤0.039) exercise. There was no significant difference in Spo2 or rSo2 between two exercise intensities. These data indicate that low to moderate exercise (i.e., 40%-60% adjusted Vo2max) may attenuate the risk of impaired cognitive function that occurs in hypoxic conditions.
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Affiliation(s)
- Yongsuk Seo
- 1 Department of Exercise Physiology, Kent State University , Kent, Ohio
| | - Keith Burns
- 1 Department of Exercise Physiology, Kent State University , Kent, Ohio
| | - Curtis Fennell
- 1 Department of Exercise Physiology, Kent State University , Kent, Ohio
| | - Jung-Hyun Kim
- 2 National Personal Protective Technology Laboratory, National Institute for Occupational Safety and Health , Centers for Disease Control and Prevention, Pittsburgh, Pennsylvania
| | - John Gunstad
- 1 Department of Exercise Physiology, Kent State University , Kent, Ohio
| | - Ellen Glickman
- 1 Department of Exercise Physiology, Kent State University , Kent, Ohio
| | - John McDaniel
- 1 Department of Exercise Physiology, Kent State University , Kent, Ohio.,3 Louis Stokes Cleveland Veterans Affairs Medical Center , Cleveland, Ohio
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Kim CH, Ryan EJ, Seo Y, Peacock C, Gunstad J, Muller MD, Ridgel AL, Glickman EL. Low intensity exercise does not impact cognitive function during exposure to normobaric hypoxia. Physiol Behav 2015; 151:24-8. [PMID: 26160408 DOI: 10.1016/j.physbeh.2015.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/16/2015] [Accepted: 07/02/2015] [Indexed: 11/30/2022]
Abstract
Exposure to hypoxia is associated with cognitive impairment, mediated by cerebral deoxygenation. This can be problematic for individuals who perform mental tasks at high altitude. Eight healthy men completed two experimental trials consisting of 5h of exposure to normobaric hypoxia (12.5% O2). In one of the experimental trials (Hypoxia) subjects remained resting in a seated position the entire 5h; in the other experimental trial (Hypoxia and Exercise) subjects rested 2h, cycled for 1h at constant wattage (workload equivalent to 50% of altitude adjusted VO2max), then rested the last 2h. Cerebral oxygenation was measured continuously via near-infrared spectroscopy and cognitive performance was assessed by Trail Making Test A and B. Cerebral oxygenation and cognitive performance both were impaired during exposure to hypoxia. In the Hypoxia and Exercise trial, subjects experienced further declinations in cerebral oxygenation without concomitant decreases in cognitive function. These data demonstrate that cognitive function declines during exposure to normobaric hypoxia and this decline is not exacerbated by low intensity exercise.
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Affiliation(s)
- Chul-Ho Kim
- Exercise Physiology, School of Health Sciences, Kent State University, Kent, OH, USA; Human Integrative and Environmental Physiology, Mayo Clinic, Rochester, MN, USA.
| | - Edward J Ryan
- Exercise Physiology, School of Health Sciences, Kent State University, Kent, OH, USA; Department of Exercise Science, Chatham University, Pittsburgh, PA, USA
| | - Yongsuk Seo
- Exercise Physiology, School of Health Sciences, Kent State University, Kent, OH, USA
| | - Corey Peacock
- Exercise Physiology, School of Health Sciences, Kent State University, Kent, OH, USA
| | - John Gunstad
- Department of Psychology, Kent State University, Kent, OH, USA
| | - Matthew D Muller
- Exercise Physiology, School of Health Sciences, Kent State University, Kent, OH, USA; Penn State Heart & Vascular Institute, Penn State University College of Medicine, Hershey, PA, USA
| | - Angela L Ridgel
- Exercise Physiology, School of Health Sciences, Kent State University, Kent, OH, USA
| | - Ellen L Glickman
- Exercise Physiology, School of Health Sciences, Kent State University, Kent, OH, USA
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Ando S, Komiyama T, Sudo M, Kiyonaga A, Tanaka H, Higaki Y. The effects of temporal neck cooling on cognitive function during strenuous exercise in a hot environment: a pilot study. BMC Res Notes 2015; 8:202. [PMID: 26025443 PMCID: PMC4467620 DOI: 10.1186/s13104-015-1210-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 05/22/2015] [Indexed: 01/08/2023] Open
Abstract
Background Heat stress potentially has detrimental effects on brain function. Hence, cognitive function may be impaired during physical activity in a hot environment. Skin cooling is often applied in a hot environment to counteract heat stress. However, it is unclear to what extent neck cooling is effective for cognitive impairment during exercise in a hot environment. The purpose of this study was to examine the effects of temporal neck cooling on cognitive function during strenuous exercise in a hot environment. Methods Eight male young participants (mean ± SD, age = 26.1 ± 3.2 years; peak oxygen uptake = 45.6 ± 5.2 ml/kg/min) performed Spatial delayed response (DR) task (working memory) and Go/No-Go task (executive function) at rest and during exercise in the Hot and Hot + Cooling conditions. After the participants completed the cognitive tasks at rest, they cycled the ergometer until their heart rate (HR) reached 160 beats/min. Then, they cycled for 10 min while keeping their HR at 160 beats/min. The cognitive tasks were performed 3 min after their HR reached 160 beats/min. The air temperature was maintained at 35°C and the relative humidity was controlled at 70%. Neck cooling was applied to the backside of the neck by a wet towel and fanning. We used accuracy of the Spatial DR and Go/No-Go tasks and reaction time in the Go/No-Go task to assess cognitive function. Results Neck cooling temporarily decreased the skin temperature during exercise. The accuracy of the cognitive tasks was lower during exercise than that at rest in the Hot and Hot + Cooling condition (p < 0.05). There were no differences in the accuracy between the Hot and Hot + Cooling conditions (p = 0.98). Neither exercise (p = 0.40) nor cooling (p = 0.86) affected reaction time. These results indicate that temporal neck cooling did not alter cognitive function during strenuous exercise in a hot environment. Conclusions The present study suggests that temporal neck cooling with a wet towel and fanning is not effective for attenuating impairment of working memory and executive function during strenuous exercise with a short duration in a warm and humid environment.
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Affiliation(s)
- Soichi Ando
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan. .,Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan.
| | - Takaaki Komiyama
- Graduate School of Sports and Health Science, Fukuoka University, Fukuoka, Japan.
| | - Mizuki Sudo
- Fukuoka University Institute for Physical Activity, Fukuoka University, Fukuoka, Japan. .,Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Tokyo, Japan.
| | - Akira Kiyonaga
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan. .,Fukuoka University Institute for Physical Activity, Fukuoka University, Fukuoka, Japan.
| | - Hiroaki Tanaka
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan. .,Fukuoka University Institute for Physical Activity, Fukuoka University, Fukuoka, Japan.
| | - Yasuki Higaki
- Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan. .,Fukuoka University Institute for Physical Activity, Fukuoka University, Fukuoka, Japan.
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Mateika JH, El-Chami M, Shaheen D, Ivers B. Intermittent hypoxia: a low-risk research tool with therapeutic value in humans. J Appl Physiol (1985) 2014; 118:520-32. [PMID: 25549763 DOI: 10.1152/japplphysiol.00564.2014] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Intermittent hypoxia has generally been perceived as a high-risk stimulus, particularly in the field of sleep medicine, because it is thought to initiate detrimental cardiovascular, respiratory, cognitive, and metabolic outcomes. In contrast, the link between intermittent hypoxia and beneficial outcomes has received less attention, perhaps because it is not universally understood that outcome measures following exposure to intermittent hypoxia may be linked to the administered dose. The present review is designed to emphasize the less recognized beneficial outcomes associated with intermittent hypoxia. The review will consider the role intermittent hypoxia has in cardiovascular and autonomic adaptations, respiratory motor plasticity, and cognitive function. Each section will highlight the literature that contributed to the belief that intermittent hypoxia leads primarily to detrimental outcomes. The second segment of each section will consider the possible risks associated with experimentally rather than naturally induced intermittent hypoxia. Finally, the body of literature indicating that intermittent hypoxia initiates primarily beneficial outcomes will be considered. The overarching theme of the review is that the use of intermittent hypoxia in research investigations, coupled with reasonable safeguards, should be encouraged because of the potential benefits linked to the administration of a variety of low-risk intermittent hypoxia protocols.
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Affiliation(s)
- Jason H Mateika
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan
| | - Mohamad El-Chami
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - David Shaheen
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Blake Ivers
- John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
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Komiyama T, Sudo M, Higaki Y, Kiyonaga A, Tanaka H, Ando S. Does moderate hypoxia alter working memory and executive function during prolonged exercise? Physiol Behav 2014; 139:290-6. [PMID: 25460539 DOI: 10.1016/j.physbeh.2014.11.057] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 11/15/2014] [Accepted: 11/17/2014] [Indexed: 12/31/2022]
Abstract
It has been suggested that acute exercise improves cognitive function. However, little is known about how exercise under hypoxia affects cognitive function. The purpose of this study was to determine if hypoxia alters working memory and executive function during prolonged exercise. Sixteen participants performed cognitive tasks at rest and during exercise under normoxia and hypoxia [fraction of inspired oxygen (FIO2)=0.15, corresponding to an altitude of approximately 2600 m]. The level of hypoxia was moderate. We used a combination of Spatial Delayed Response (Spatial DR) task and Go/No-Go (GNG) task, where spatial working memory and executive function are required. Working memory was assessed by the accuracy of the Spatial DR task, and executive function was assessed by the accuracy and reaction time in the GNG task. The participants cycled an ergometer for 30 min under normoxia and moderate hypoxia while keeping their heart rate (HR) at 140 beats/min. They performed the cognitive tasks 5 min and 23 min after their HR reached 140 beats/min. Moderate hypoxia did not alter the accuracy of the Spatial DR (P=0.38) and GNG tasks (P=0.14). In contrast, reaction time in the GNG task significantly decreased during exercise relative to rest under normoxia and moderate hypoxia (P=0.02). These results suggest that moderate hypoxia and resultant biological processes did not provide sufficient stress to impair working memory and executive function during prolonged exercise. The beneficial effects on speed of response appear to persist during prolonged exercise under moderate hypoxia.
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Affiliation(s)
- Takaaki Komiyama
- Graduate School of Sports and Health Science, Fukuoka University, Japan
| | - Mizuki Sudo
- Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Tokyo, Japan; Fukuoka University Institute for Physical Activity, Fukuoka University, Japan
| | - Yasuki Higaki
- Fukuoka University Institute for Physical Activity, Fukuoka University, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan
| | - Akira Kiyonaga
- Fukuoka University Institute for Physical Activity, Fukuoka University, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan
| | - Hiroaki Tanaka
- Fukuoka University Institute for Physical Activity, Fukuoka University, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan
| | - Soichi Ando
- Faculty of Sports and Health Science, Fukuoka University, Japan; Graduate School of Informatics and Engineering, The University of Electro-communications, Japan.
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Horiuchi M, Endo J, Takayama N, Murase K, Nishiyama N, Saito H, Fujiwara A. Impact of viewing vs. not viewing a real forest on physiological and psychological responses in the same setting. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:10883-901. [PMID: 25333924 PMCID: PMC4211012 DOI: 10.3390/ijerph111010883] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/08/2014] [Accepted: 10/14/2014] [Indexed: 12/19/2022]
Abstract
We investigated the impact of viewing versus not viewing a real forest on human subjects’ physiological and psychological responses in the same setting. Fifteen healthy volunteers (11 males, four females, mean age 36 years) participated. Each participant was asked to view a forest while seated in a comfortable chair for 15 min (Forest condition) vs. sitting the same length of time with a curtain obscuring the forest view (Enclosed condition). Both conditions significantly decreased blood pressure (BP) variables, i.e., systolic BP, diastolic BP, and mean arterial pressure between pre and post experimental stimuli, but these reductions showed no difference between conditions. Interestingly, the Forest viewing reduced cerebral oxygenated hemoglobin (HbO2) assessed by near-infrared spectroscopy (NIRS) and improved the subjects’ Profile of Mood States (POMS) scores, whereas the Enclosed condition increased the HbO2 and did not affect the POMS scores. There were no significant differences in saliva amylase or heart rate variability (HRV) between the two conditions. Collectively, these results suggest that viewing a real forest may have a positive effect on cerebral activity and psychological responses. However, both viewing and not viewing the forest had similar effects on cardiovascular responses such as BP variables and HRV.
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Affiliation(s)
- Masahiro Horiuchi
- Division of Human Environmental Science, Mt. Fuji Research Institute, 5597-1, Kami-Yoshida, Fuji-Yoshida City, Yamanashi 4030005, Japan.
| | - Junko Endo
- Division of Human Environmental Science, Mt. Fuji Research Institute, 5597-1, Kami-Yoshida, Fuji-Yoshida City, Yamanashi 4030005, Japan.
| | - Norimasa Takayama
- Department of Forest Management, Forestry and Forest Products Research Institute, 1 Matsuno-sato, Tsukuba City, Ibaraki 305-8687, Japan.
| | - Kazutaka Murase
- Fuji Iyashinomoroi Woodland Study Center, The University of Tokyo, Yamanaka 341-2, Yamanakako Village, Minami-tsuru, Yamanashi 4010501, Japan.
| | - Norio Nishiyama
- Fuji Iyashinomoroi Woodland Study Center, The University of Tokyo, Yamanaka 341-2, Yamanakako Village, Minami-tsuru, Yamanashi 4010501, Japan.
| | - Haruo Saito
- Fuji Iyashinomoroi Woodland Study Center, The University of Tokyo, Yamanaka 341-2, Yamanakako Village, Minami-tsuru, Yamanashi 4010501, Japan.
| | - Akio Fujiwara
- Fuji Iyashinomoroi Woodland Study Center, The University of Tokyo, Yamanaka 341-2, Yamanakako Village, Minami-tsuru, Yamanashi 4010501, Japan.
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Ogoh S, Tsukamoto H, Hirasawa A, Hasegawa H, Hirose N, Hashimoto T. The effect of changes in cerebral blood flow on cognitive function during exercise. Physiol Rep 2014; 2:2/9/e12163. [PMID: 25263210 PMCID: PMC4270220 DOI: 10.14814/phy2.12163] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
No studies have identified the direct effect of changes in cerebral blood flow (CBF) on cognitive function at rest and during exercise. In this study, we manipulated CBF using hypercapnic gas to examine whether an increase in CBF improves cognitive function during prolonged exercise. The speed and the accuracy of cognitive function were assessed using the Stroop color-word test. After the Stroop test at rest, the subjects began exercising on a cycling ergometer in which the workload was increased by 0.5 kilopond every minute until a target heart rate of 140 beats/min was achieved. Then, the subjects continued to cycle at a constant rate for 50 min. At four time points during the exercise (0, 10, 20, 50 min), the subjects performed a Stroop test with and without hypercapnic respiratory gas (2.0% CO2), with a random order of the exposures in the two tests. Despite a decrease in the mean blood flow velocity in the middle cerebral artery (MCA Vmean), the reaction time for the Stroop test gradually decreased during the prolonged exercise without any loss of performance accuracy. In addition, the hypercapnia-induced increase in MCA Vmean produced neither changes in the reaction time nor error in the Stroop test during exercise. These findings suggest that the changes in CBF are unlikely to affect cognitive function during prolonged exercise. Thus, we conclude that improved cognitive function may be due to cerebral neural activation associated with exercise rather than global cerebral circulatory condition.
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Affiliation(s)
- Shigehiko Ogoh
- Graduate School of Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Hayato Tsukamoto
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Ai Hirasawa
- Graduate School of Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Hiroshi Hasegawa
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | | | - Takeshi Hashimoto
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
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Moore CM, Swain DP, Ringleb SI, Morrison S. The Effects of Acute Hypoxia and Exercise on Marksmanship. Med Sci Sports Exerc 2014; 46:795-801. [DOI: 10.1249/mss.0000000000000148] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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