有篇小型研究指出，規律運動的年輕女性，大腦內有比較多氧氣循環，頭腦可能會比較敏銳。
　　
　　研究人員表示，這篇針對52位健康年輕女性所做的研究結果，並未證明運動會讓你更聰明。
　　
　　紐西蘭Otago大學的研究人員Liana Machado表示，另一方面，這篇研究「合理」地認為，即使是年輕且健康的人，運動還是可能增進心智能力。
　　
　　這篇研究指出，依照大腦成像顯示，年輕女性大腦的氧氣供給與運動習慣息息相關。
　　
　　與較少活動的年輕女性相比，每週運動最多天的女性在做一連串需花費心智的工作時，額葉的氧氣循環較多。額葉掌管一些重要的功能，像是規劃、做決定、以及保存長期記憶等能力。
　　
　　Machado的團隊發現，好動的女性在做「認知抑制控制」的測試時，成績特別好；這是用自我控制來抑制反射性反應，替代重要反應的能力。
　　
　　要做多久的運動？研究結果指出，適度的運動就足夠，但重要的是須測試，是否較激烈的運動會有更好的效益。
　　
　　資料來源：http://www.24drs.com/WebMD/chinese_t.asp?page=1&who=091e9c5e810ce78d

Exercise May Tone Up Women's Bodies and Minds

Young women who regularly exercise may have more oxygen circulating in their brains -- and possibly sharper minds, a small study suggests.

The findings, from a study of 52 healthy young women, don't prove that exercise makes you smarter, researchers said.

On the other hand, it's "reasonable" to conclude that exercise likely boosts mental prowess even when people are young and healthy, said Liana Machado, of the University of Otago in New Zealand, the lead researcher on the study.

Previous studies have found that older adults who exercise tend to have better blood flow in the brain, and do better on tests of memory and other mental skills, versus sedentary people of the same age, the authors point out.

But few studies have focused on young adults, they said. The women in this study were between 18 and 30.

The "predominant view" has been that young adults' brains are operating at their lifetime peak, no matter what their exercise level, the researchers write in the journalPsychophysiology.

But in this study, brain imaging showed that the oxygen supply in young women's brains did vary depending on their exercise habits.

Compared with their less-active peers, women who exercised most days of the week had more oxygen circulating in the frontal lobe during a battery of mental tasks, the study found.

The frontal lobe governs some vital functions, including the ability to plan, make decisions and retain memories longer-term.

Machado's team found that active women did particularly well on tasks that measured "cognitive inhibitory control."

"That refers to the ability to suppress reflexive responses and instead respond strategically, using self-control," Machado explained.

That skill turns up a lot in daily life, she noted, whether in playing a video game or driving a car.

Similarly, the researchers found a link between higher brain oxygen levels and women's performance on the toughest test in the battery -- where the challenge was to combine inhibitory control with multitasking.

None of that proves cause-and-effect, Machado said.

But, she added, "it seems reasonable to deduce that a causal relationship likely exists -- where regular physical activity increases oxygen availability in the brain, which in turn supports better cognitive performance, particularly for more challenging tasks."

Another researcher said that when it comes to exercise and brain health, there is always a "chicken-or-egg" question.

It's possible that the young women who did better on the mental tasks were more likely to choose healthy habits because the frontal lobe is involved in "orchestrating a plan," said Sandra Bond Chapman, chief director of the Center for BrainHealth at the University of Texas at Dallas.

Chapman, who was not involved in the study, said it would be helpful for researchers to follow groups of people long-term to see whether those who adopt healthy habits end up sharpening their mental skills.

That said, Chapman encouraged people to lace up their sneakers and "get moving."

"There is growing scientific evidence that physical exercise is good for the body and the brain, no matter the age," she said.

And how much exercise would be enough to benefit a young person's brain? It's not clear, said Machado.

Women in this study were considered to be meeting guidelines on regular exercise if they got at least 30 minutes of moderate activity (such as brisk walking) or 15 minutes of vigorous activity (such as running) at least five days a week.

So the findings suggest that moderate amounts of exercise would "suffice," Machado said. "But it will be important to test whether more vigorous exercise affords greater benefits," she added.

Future studies should also focus on young men, Machado said, since women and men differ in the way the brain's vasculature (system of blood vessels) functions.

"It can't be assumed that similar findings will arise in men," she said.

More information

The Society for Neuroscience has more on exercise and the brain.

SOURCES: Liana Machado, Ph.D., senior lecturer, psychology, University of Otago, Dunedin, New Zealand; Sandra Bond Chapman, Ph.D., chief director, Center for BrainHealth, University of Texas at Dallas; Dec. 11, 2014, Psychophysiology online