肥胖、心血管適能與抑制相關執行功能之關係：事件相關電位研究

Obesity and Cardiovascular Fitness Associated with Inhibition of Executive Function: An ERP study

緒論：過去許多研究已發現肥胖對於執行功能的負面效應，而心血管適能則被發現與增進抑制相關執行功能有所關聯。本研究之目的在同時肥胖、心血管適能探討其與抑制相關執行功能之關聯。此外，本研究亦採用事件相關電位進一步探討該些變項與神經電位活動之關聯。具體而言，本研究依肥胖與心血管適能狀態比較參與者在抑制相關型態執行功能表現，以及事件相關電位P3成分之差異。方法：本研究首先以52位健康的男大生為粗篩的數，參與者需符合身體質量指數與最大攝氧量的篩選標準，最終符合條件的參與者共有40位，並將其分為正常體重高心血管適能組、肥胖高心血管適能組、正常體重低心血管適能組，以及肥胖低心血管適能組。認知功能與事件相關電位檢測採用叫色作業之反應時間與正確率，及其所誘發之P3成分。結果：正常體重高心血管適能組在異質情境作業的反應時間顯著快於肥胖低心血管適能組；同樣地，相較於正常體重高心血管適能組，肥胖低心血管適能組與肥胖高心血管適能組顯著更小的P3振幅。然P3潛伏時間並未呈現肥胖與心血管適能在不同組別的差異。結論：本研究發現，低肥胖且高心血管適能水準者在叫色任務表現最佳，其並可投入較多之注意力資源配置於執行功能相關之認知表現情境。高肥胖程度且低心血管適能水準者在叫色作業任務則最差，而肥胖者與低認知表現之關聯可能受到心血管適能的調節。建立於本研究的發現，建議未來研究可由樣本數、不同認知測驗、其他年齡組群、性別，以及更多影響肥胖者與認知功能的變項等方面作後續探討。

Introduction: Previous studies have suggested that obesity negatively affects executive function and cardiovascular fitness moderates such a relationship by enhancing the inhibition aspect of executive function. The purpose of this study was to simultaneously explore the association of both obesity and cardiovascular fitness on the inhibition of executive function and to reveal the neuroelectric activity through measuring event-related potentials (ERP). Specifically, this study was performed to compare different levels of cardiovascular fitness between young adults with obese and normal state on the inhibition of executive function and the P3 component, respectively. Methods: Fifty-two healthy male college students were first recruited and then screened for body mass index and maximal oxygen uptake. A total of forty participants meeting the criteria entered the study and they were categorized into four groups: obese young males with low cardiovascular fitness or high cardiovascular fitness, and normal-weight young males with either low cardiovascular fitness or high cardiovascular fitness. Inhibition of executive function was assessed by their response times and accuracy of performance on a Stroop test, during which the P3 amplitude and latency were recorded. Results: Regarding the Stroop test, normal-weight young males with high cardiovascular fitness had shorter response times compared to those of young males with low cardiovascular fitness. Concerning the P3 component of ERP, normal-weight young males with high cardiovascular fitness showed larger P3 amplitude compared to that of the obese young males, irrespective of their specific cardiovascular fitness levels, whereas no group differences were identified on P3 latency. Conclusion: Our findings suggest that, in contrast to obesity with low cardiovascular fitness, normal body weight coupled with high cardiovascular fitness facilitates an inhibition of executive functioning, which may in turn enhance attentional resource allocation among young males. Therefore, cardiovascular fitness could moderate the relationship between obesity and cognitive function. Future research is recommended, to include in design larger sample sizes, different cognitive tests, different populations, and other variables related to both obesity and cognitive function.