不少高、初中临近毕业考试的学生,夜晚学习常以浓茶或咖啡作为醒脑饮料,许多父母也为孩子如此用功的表现所感动。殊不知,浓茶和咖啡少饮虽然具有益智提神等作用,但是,过浓过量则会有害。浓茶和咖啡中有较多的咖啡碱,能刺激胃液分泌量,及增加酸度,使上腹嘈杂、不适,加剧胃、十二指肠溃疡,还可造成心动过速、心律不齐、兴奋不安。日本的研究证明,饮咖啡2小时后,人体血中游离脂肪酸、乳酸、丙酮酸及血糖都升高;如 Many high, junior high school graduation exam students often learn tea or coffee at night as a refreshing drink, many parents are also impressed by the performance of children so hard. As everyone knows, tea and coffee drink less although it has the effect of puzzle refreshing, however, too much will be harmful. More tea and coffee caffeine, can stimulate the secretion of gastric juice, and increased acidity, so that noisy abdominal, discomfort, increased stomach, duodenal ulcer, can also cause tachycardia, arrhythmia, excitement . Japanese studies have shown that 2 hours after drinking coffee, human blood free fatty acids, lactate, pyruvate and blood sugar are elevated; such as