The mid-term exam period is over. During the time, students try to spend extra hours for studying, often staying late at night. For doing so, the most frequently used is coffee. Coffee is commonly consumed drink worldwide. Its active substance is not too hard to name - caffeine. Caffeine is a naturally occurring stimulant to central nervous system and rich in coffee beans. Tea leaves, cocoa beans, and kola nuts also contain caffeine.
  Caffeine consumed moderately can help improve memory, concentration and cognitive performance. Problems occur when it is over-ingested. Too much caffeine causes undesirable side-effects, including jittery feeling, anxiety, and even loss of concentration. 
  How much caffeine is ‘moderate’ or ‘too much’? The acceptable daily intake of caffeine is less than 400 mg of caffeine per day for adults. Caffeine content of commercial coffee drinks vary but are typically 100 to 200 mg per one serving cup of coffee. Over 600 mg of caffeine per day is regarded as an unsafe dose. Try not to drink more than 2-4 servings per day. Some energy drinks found in the markets also contain significant amount of caffeine, even up to approximately 200 mg. When you choose and select caffeine beverages, it is good to have a habit to see if there is any information on caffeine content in the package and to read the label.
  Does caffeine have no health benefits at all in any cases? Well, it has been suggested that adequate amount of caffeine have potential health benefits, including reduced risk of type-2 diabetes, cardiovascular diseases, some types of cancers, and neurodegenerative diseases. But it is still important to remember that such health benefits are not conclusive and the overdose of caffeine may have adverse effects.
  When you prepare exams, in addition to avoiding too much caffeine, you try to eat well and exercise. This will help your brain active and so you think clearly and study efficiently during daytime. You may want to do an experiment by yourself to see which is better, over-drinking caffeine and staying all night, or limiting caffeine, eating well, being active during daytime, and getting a good night’s sleep. Determine what you will do during the next exam period. Wish you be more successful in schools.