A cup of freshly ground coffee is what it takes to get some people moving in the morning.

    But, according to a study, it may be the aroma rather than the coffee itself that does the trick.

    Researchers believe that the aroma of roasted coffee beans can soothe frayed nerves - and that just the whiff could be enough to reverse the effects of a poor night's sleep on the brain.

    Aroma: Just smelling coffee can help cure tiredness better than drinking a cup

    They said that chemicals extracted from coffee and pumped into the air may one day be used as a way of reviving tired people.

    Scientists in Tsukuba, Japan, kept 16 laboratory rats awake for 24 hours, by keeping them in a cage filled with an inch of water, then exposed half of them to the smell of roasted coffee.

    After taking samples of the rats' brains, they found that the smell of coffee boosted the activity of key genes that promote cell survival in the body and reduce anxiety, New Scientist magazine reports today.

    Professor Yoshinori Masuo, who led the study in Tsukuba, Japan, said that when people drink coffee to stay up all night, just the smell of the coffee could alleviate some of the stress caused by sleeplessness.

    He added: 'Is it better for us to smell coffee bean aroma than to drink coffee, or would any other food-related odour produce similar effects? Further studies are needed.'

    清晨起來，一杯新鮮的研磨咖啡可以讓人精力充沛。

    但一項最新的研究表明，這種功效可能是咖啡的香氣而不是咖啡本身產生的。

    研究人員相信，烘培咖啡豆的香氣可以安撫緊張的神經-而且只是一點點香氣就可以緩解整夜失眠對大腦造成的影響。

    香氣: 僅僅聞咖啡比喝一杯咖啡更能幫助緩解疲勞

    他們說，早晚有一天可以通過提取咖啡中的化學物質并釋放到空氣中，來緩解人們的疲勞。

    日本筑波的科學家們把16只小白鼠放到有1英寸深的水的籠子里，這樣保證它們24小時不睡覺。然后，將一半的老鼠放在烘培咖啡的香氣中。

    在對小白鼠大腦取樣后，他們發現咖啡的氣味，增強了關鍵基因的活動，這種基因活動可以促進體內細胞存活，并且減少焦慮。

    領導日本筑波研究團隊的益男教授說，當人們為了熬夜而喝咖啡時，僅僅是咖啡的味道就會減輕由不睡覺而產生的壓力。

    他補充說：'聞咖啡豆的氣味要比喝咖啡更好。但是否其他食物的氣味會產生類似效應呢？這還需要進一步的研究。