title: Does moderate hypoxia alter working memory and executive function during prolonged exercise?
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.
authors.affiliation: Graduate School of Sports and Health Science, Fukuoka University, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Komiyama
authors.affiliation: Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Tokyo, Japan; Fukuoka University Institute for Physical Activity, Fukuoka University, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Sudo
authors.affiliation: Fukuoka University Institute for Physical Activity, Fukuoka University, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Higaki
authors.affiliation: Fukuoka University Institute for Physical Activity, Fukuoka University, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kiyonaga
authors.affiliation: Fukuoka University Institute for Physical Activity, Fukuoka University, Japan; Faculty of Sports and Health Science, Fukuoka University, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Faculty of Sports and Health Science, Fukuoka University, Japan; Graduate School of Informatics and Engineering, The University of Electro-communications, Japan. Electronic address: soichi.ando@uec.ac.jp.
authors.forename: Soichi
authors.initials: S
authors.lastname: Ando
mesh_terms: D001642:Bicycling / Q000502:physiology; D056344:Executive Function / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism; D011581:Psychological Tests; D011930:Reaction Time; D012146:Rest / Q000502:physiology; D065852:Spatial Memory / Q000502:physiology; D055815:Young Adult
chemical_list: D019344:Lactic Acid; D010100:Oxygen
keywords: Cognition; Oxygen availability; Reaction time