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The effects of acute exercise and hypoxia on cognitive function
International Journal of Psychophysiology 94 (2014) 120–261
approaches, including transcranial Doppler (TCD) ultrasonography, near-infrared spectroscopy (NIRS), magnetic resonance imaging (MRI), electroencephalogram (EEG), and event-related potentials (ERPs). These psychophysiological data lead to a deeper understanding of the effects of exercise on the human brain and cognition.
doi:10.1016/j.ijpsycho.2014.08.629
Effect of pressor response on increase response in cerebral blood flow to visual stimulation at rest and during exercise Naoyuki Hayashia, Yuji Yamaguchib a Tokyo Institute of Technology, Japan b Graduate School of Kyushu University, Japan Background: Adequate blood flow is necessary in the brain, particularly in a working region. This is secured by the neurovascular coupling (NVC), which is defined as adjustment of the local cerebral blood flow according to an underlying cortical neural activity. NVC is assessed as a magnitude of an increase response to a given visual stimulation in the blood flow velocity in the posterior cerebral artery (PCAv), which supplies blood to the visual cortex. The response in PCAv, i.e., NVC, can be theoretically induced by vasodilation in the artery and/or its downstream, and an increase in blood pressure (pressor response). Still information is limited on contributions of regional vasodilation and pressor response on NVC. Also, an effect of exercise on NVC is unclear while a study reported unchanged NVC during dynamic exercise at 70% of the maximum heart rate (Willie et al. 2011). In the present study, then, to examine an effect of pressor response on NVC during various exercises, and to investigate an effect of exercise on NVC, we measured the PCAv and blood pressure during static exercise and dynamic exercises at various intensities in healthy males. Methods: Seventeen subjects performed a 2-min static handgrip at 30% of the maximum voluntary contraction, and 14 subjects performed 12-min submaximal leg-cycle exercises at heart rates of 120, 140, and 160 bpm. PCAv and blood pressure were continuously recorded by a Doppler ultrasound flowmetry and Finometer, respectively. NVC was estimated as the relative change in PCAv from the mean value obtained during 20 s of eye closing period to the peak value obtained during 40 s of visual stimulation involving looking at a reversed checkerboard. The conductance index (CI) of the artery was calculated by dividing PCAv by the mean blood pressure. Results: Visual stimulation significantly increased PCAv at rest and during all exercises, and significantly increased blood pressure at rest, and during static and 140-bpm exercises. All exercises significantly increased pre-stimulation PCAv. The intensity of dynamic exercise significantly affected the peak response, and no difference in peak value was observed. Static exercise did not significantly change the magnitude of NVC while it significantly inhibited CI response. Discussion and Conclusion: These suggest that NVC was maintained during static and submaximal dynamic exercises, and pressor response to visual stimulation plays a role, at least partly, for securing the NVC at rest and during exercises. This study was supported by Kozuki Foundation.
doi:10.1016/j.ijpsycho.2014.08.630
135
The effects of acute exercise and hypoxia on cognitive function Soichi Andoa, Takaaki Komiyamab, Mizuki Sudoc, Yasuki Higakid Graduate School of Informatics and Engineering, The University of Electro-Communications, Japan b Graduate School of Sports and Health Science, Fukuoka University, Japan c Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Japan d Faculty of Sports and Health Science, Fukuoka University, Japan a
Cognitive function is fundamentally important to most human activities. There is a growing body of evidence to suggest that cognitive function improves during a single bout of moderate exercise. In contrast, hypoxia potentially has detrimental effects on cognitive function because of brain desaturation and consequent biological process. These findings imply that cognitive function during exercise under hypoxia may be determined by the balance between these beneficial and detrimental effects. However, little is known about how cognitive function is altered during exercise under hypoxia. Understanding the factors that affect this balance may ultimately contribute to our understanding of the exercise–cognition interaction at high altitude. In a series of our studies, we used speed of response (reaction time) and accuracy of the cognitive task to assess cognitive function. In the first study, we have shown that reaction time decreased during moderate exercise under normoxia. In contrast, accuracy was not affected during exercise. In the second study, we examined the effects of exercise at various fractions of inspired oxygen (FIO2: 0.209, 0.18, and 0.15) on cognitive function. SpO2 and cerebral oxygenation progressively decreased during exercise as the FIO2 level decreased. Nevertheless, reaction time decreased during moderate exercise without affecting accuracy in all FIO2 conditions. In the third study, we used demanding cognitive tasks, where spatial working memory and executive function are required, to test if task difficulty affects the combined effects of exercise and moderate hypoxia (FIO2 = 0.15). Again, reaction time decreased during exercise under normoxia and moderate hypoxia. Moderate hypoxia did not alter the accuracy of cognitive tasks. These results suggest that the beneficial effects on speed of response appear to persist during exercise under moderate hypoxia. Moderate hypoxia and resultant biological processes may not be sufficient enough to impair cognitive function during exercise. Finally, combined effects of exercise and hypoxia on cognitive function will be discussed based on these findings. doi:10.1016/j.ijpsycho.2014.08.631
Exercise and brain health in older adults with mild cognitive impairment Hyuma Makizako, Hiroyuki Shimada National Center for Geriatrics and Gerontology, Japan
There is growing evidence that physical activity (PA) is associated with reduced risk of dementia. We present an overview of the association between PA and brain health, and the effects of multicomponent exercise on cognitive function in older adults with mild cognitive impairment (MCI). In our cross-sectional study, 310 older adults with MCI (mean age: 71.3 years) underwent neuropsychological memory testing and structural magnetic resonance imaging. Average daily PA duration was calculated using triaxial accelerometers. We conducted a randomized trial to determine the effects of a multicomponent exercise program (90 min/d, 2 d/week, 40 times for 6 months) on cognitive function in older adults with MCI (n = 100). Moderate-
approaches, including transcranial Doppler (TCD) ultrasonography, near-infrared spectroscopy (NIRS), magnetic resonance imaging (MRI), electroencephalogram (EEG), and event-related potentials (ERPs). These psychophysiological data lead to a deeper understanding of the effects of exercise on the human brain and cognition.
doi:10.1016/j.ijpsycho.2014.08.629
Effect of pressor response on increase response in cerebral blood flow to visual stimulation at rest and during exercise Naoyuki Hayashia, Yuji Yamaguchib a Tokyo Institute of Technology, Japan b Graduate School of Kyushu University, Japan Background: Adequate blood flow is necessary in the brain, particularly in a working region. This is secured by the neurovascular coupling (NVC), which is defined as adjustment of the local cerebral blood flow according to an underlying cortical neural activity. NVC is assessed as a magnitude of an increase response to a given visual stimulation in the blood flow velocity in the posterior cerebral artery (PCAv), which supplies blood to the visual cortex. The response in PCAv, i.e., NVC, can be theoretically induced by vasodilation in the artery and/or its downstream, and an increase in blood pressure (pressor response). Still information is limited on contributions of regional vasodilation and pressor response on NVC. Also, an effect of exercise on NVC is unclear while a study reported unchanged NVC during dynamic exercise at 70% of the maximum heart rate (Willie et al. 2011). In the present study, then, to examine an effect of pressor response on NVC during various exercises, and to investigate an effect of exercise on NVC, we measured the PCAv and blood pressure during static exercise and dynamic exercises at various intensities in healthy males. Methods: Seventeen subjects performed a 2-min static handgrip at 30% of the maximum voluntary contraction, and 14 subjects performed 12-min submaximal leg-cycle exercises at heart rates of 120, 140, and 160 bpm. PCAv and blood pressure were continuously recorded by a Doppler ultrasound flowmetry and Finometer, respectively. NVC was estimated as the relative change in PCAv from the mean value obtained during 20 s of eye closing period to the peak value obtained during 40 s of visual stimulation involving looking at a reversed checkerboard. The conductance index (CI) of the artery was calculated by dividing PCAv by the mean blood pressure. Results: Visual stimulation significantly increased PCAv at rest and during all exercises, and significantly increased blood pressure at rest, and during static and 140-bpm exercises. All exercises significantly increased pre-stimulation PCAv. The intensity of dynamic exercise significantly affected the peak response, and no difference in peak value was observed. Static exercise did not significantly change the magnitude of NVC while it significantly inhibited CI response. Discussion and Conclusion: These suggest that NVC was maintained during static and submaximal dynamic exercises, and pressor response to visual stimulation plays a role, at least partly, for securing the NVC at rest and during exercises. This study was supported by Kozuki Foundation.
doi:10.1016/j.ijpsycho.2014.08.630
135
The effects of acute exercise and hypoxia on cognitive function Soichi Andoa, Takaaki Komiyamab, Mizuki Sudoc, Yasuki Higakid Graduate School of Informatics and Engineering, The University of Electro-Communications, Japan b Graduate School of Sports and Health Science, Fukuoka University, Japan c Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Japan d Faculty of Sports and Health Science, Fukuoka University, Japan a
Cognitive function is fundamentally important to most human activities. There is a growing body of evidence to suggest that cognitive function improves during a single bout of moderate exercise. In contrast, hypoxia potentially has detrimental effects on cognitive function because of brain desaturation and consequent biological process. These findings imply that cognitive function during exercise under hypoxia may be determined by the balance between these beneficial and detrimental effects. However, little is known about how cognitive function is altered during exercise under hypoxia. Understanding the factors that affect this balance may ultimately contribute to our understanding of the exercise–cognition interaction at high altitude. In a series of our studies, we used speed of response (reaction time) and accuracy of the cognitive task to assess cognitive function. In the first study, we have shown that reaction time decreased during moderate exercise under normoxia. In contrast, accuracy was not affected during exercise. In the second study, we examined the effects of exercise at various fractions of inspired oxygen (FIO2: 0.209, 0.18, and 0.15) on cognitive function. SpO2 and cerebral oxygenation progressively decreased during exercise as the FIO2 level decreased. Nevertheless, reaction time decreased during moderate exercise without affecting accuracy in all FIO2 conditions. In the third study, we used demanding cognitive tasks, where spatial working memory and executive function are required, to test if task difficulty affects the combined effects of exercise and moderate hypoxia (FIO2 = 0.15). Again, reaction time decreased during exercise under normoxia and moderate hypoxia. Moderate hypoxia did not alter the accuracy of cognitive tasks. These results suggest that the beneficial effects on speed of response appear to persist during exercise under moderate hypoxia. Moderate hypoxia and resultant biological processes may not be sufficient enough to impair cognitive function during exercise. Finally, combined effects of exercise and hypoxia on cognitive function will be discussed based on these findings. doi:10.1016/j.ijpsycho.2014.08.631
Exercise and brain health in older adults with mild cognitive impairment Hyuma Makizako, Hiroyuki Shimada National Center for Geriatrics and Gerontology, Japan
There is growing evidence that physical activity (PA) is associated with reduced risk of dementia. We present an overview of the association between PA and brain health, and the effects of multicomponent exercise on cognitive function in older adults with mild cognitive impairment (MCI). In our cross-sectional study, 310 older adults with MCI (mean age: 71.3 years) underwent neuropsychological memory testing and structural magnetic resonance imaging. Average daily PA duration was calculated using triaxial accelerometers. We conducted a randomized trial to determine the effects of a multicomponent exercise program (90 min/d, 2 d/week, 40 times for 6 months) on cognitive function in older adults with MCI (n = 100). Moderate-