Drinking in Standing up Position
In the islamic law version is there several hadis states that Rasulullah was ever been drinking both while standing or sitting position, but the most popular opinion and most widely followed by many islamic community in the world is from Imam nawawi's statement like as written in his book titled "syarah al- muslim" (commentary notes upon the book of Hadith Imam Muslim), He says that drinking with standing position is Makruh Tanzih, the meaning like mentioned in the book of "al-waraqat" by Imam haramain, Makruh Tanzih is refers to an act that is no promise of punishment for the one who carries it out, but left it out is better. But in this case is excluded if the drink Zamzam water, because drinking Zamzam water with standing position is Sunnah.
So, drinking with sitting down is better than drinking with standing up, This conclusion may be based on that there negative effects when drinking in a standing position, in the most popular islamic literature titled "I'anatu at-tholibin" quoted from Imam Ibn Qoyyim's explanation, he says that drinking in standing position is causes the water can not be retained in stomach, and can not be spread to other parts of the body, but the water will be continue going down, and this will be make the human body is dehydrated, although he is drinking many lots of water.