title: Cerebral oxygenation during intermittent supramaximal exercise.
abstract: This study examined cerebral deoxygenation during intermittent supramaximal exercise in six healthy male subjects (age: 27.2 +/- 0.6 years (mean +/- S.E.). The subjects performed seven times exercise at an intensity corresponding to 150% of maximal oxygen uptake (VO2max) on cycle ergometer (30 s exercise/15 s rest). Cerebral oxygenation was measured by near-infrared spectroscopy (NIRS). The peak blood lactate concentration after exercise was 15.3 +/- 0.2 mmol/l. Cerebral oxygenation increased in first repetition compared with at rest (+ 5.7 +/- 0.6 microM; P < 0.05), but then decreased with time. Thus, in the last repetition cerebral oxygenation was - 8.5 +/- 0.4 microM (P < 0.05). There was no significant change in arterial oxygen saturation (99.6 +/- at rest, 98.4 +/- 0.2 at the final set of intermittent exercise), and there was no correlated change in end-tidal CO2 concentration with cerebral oxygenation (P > 0.05). These findings suggest that the fatigue resulting from dynamic severe exercise related to a decrease in the cerebral oxygenation level.
authors.affiliation: Graduate School of Human-Environment Studies, Kyushu University, 6-1 Kasuga-koen, Kasuga City, Fukuoka 816-8580, Japan. SHIBUYA_ken-ichi@ihs.kyushu-u.ac.jp
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Shibuya
authors.forename: Junya
authors.initials: J
authors.lastname: Tanaka
authors.forename: Naomi
authors.initials: N
authors.lastname: Kuboyama
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Ogaki
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000378:metabolism*; D016552:Ergometry / Q000379:methods; D015444:Exercise / Q000502:physiology*; D006454:Hemoglobins; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D010108:Oxyhemoglobins; D012119:Respiration; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; D019344:Lactic Acid