Effect of age on exercise-induced alterations in cognitive executive function: Relationship to cerebral perfusion

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• 作者：Samuel J.E. Lucas ; Philip N. Ainslie ; Carissa J. Murrell ; Kate N. Thomas ; Elizabeth A. Franz ; James D. Cotter
• 关键词：CBF ; cerebral blood flow ; HHb ; deoxyhemoglobin ; HRR ; heart rate range ; MCAv ; middle cerebral artery blood flow velocity ; NIRS ; near infrared spectroscopy ; O2Hb ; oxyhemoglobin ; PCO2 ; partial pressure of CO2 ; PETCO2 ; partial pressure of end tidal CO2 ; tHb
• 刊名：Experimental Gerontology
• 出版年：2012
• 出版时间：August, 2012
• 年：2012
• 卷：47
• 期：8
• 页码：541-551
• 全文大小：1129 K

文摘

Regular exercise improves the age-related decline in cerebral blood flow (CBF) and is associated with improved cognitive function; however, less is known about the direct relationship between CBF and cognitive function. We examined the influence of healthy aging on the capability of acute exercise to improve cognition, and whether exercise-induced improvements in cognition are related to CBF and cortical hemodynamics. Middle cerebral artery blood flow velocity (MCAv; Doppler) and cortical hemodynamics (NIRS) were measured in 13 young (24 ¡À 5 y) and 9 older (62 ¡À 3 y) participants at rest and during cycling at 30 % and 70 % of heart rate range (HRR). Cognitive performance was assessed using a computer-adapted Stroop task (i.e., test of executive function cognition) at rest and during exercise. Average response times on the Stroop task were slower for the older compared to younger group for both simple and difficult tasks (P < 0.01). Independent of age, difficult-task response times improved during exercise (P < 0.01), with the improvement greater at 70 % HRR exercise (P = 0.04 vs. 30 % HRR). Higher MCAv was correlated with faster response times for simple and difficult tasks at rest (R² = 0.47 and R² = 0.47, respectively), but this relation uncoupled progressively during exercise. Exercise-induced increases in MCAv were similar and unaltered during cognitive tasks for both age groups. In contrast, prefrontal cortical hemodynamic NIRS measures [oxyhemoglobin (O₂Hb) and total hemoglobin (tHb)] were differentially affected by exercise intensity, age and cognitive task; e.g., there were smaller increases in [O₂Hb] and [tHb] in the older group between exercise intensities (P < 0.05). These data indicate that: 1) Regardless of age, cognitive (executive) function is improved while exercising; 2) while MCAv is strongly related to cognition at rest, this relation becomes uncoupled during exercise, and 3) there is dissociation between global CBF and regional cortical oxygenation and NIRS blood volume markers during exercise and engagement of prefrontal cognition.