In student life, sleep is considered as a deadly enemy. It seems like its pulling you off from reaching your goals. You feel more sleepy when exams are just around the corner. Isn't it?
Your sitting position matters a lot while studying for longhours. try to sit on a chair, it will help you stay active. avoid table fanwhile you are studying, before studying don't eat heavy meal, this will make yousleepy.
While studying, first you should decide your place for study and your sitting position. You should keep lights in your room switched on. Do not have a heavy meal just before the study. When you lie on your bed while studying you may get into the lazy mode. Hence do not lie in the bed and study. If you don't want to lose concentration while studying, you should meditate for at least 20 minutes daily, concentrating on one specific thing at a time