Historically part of Midlothian, the city has long been a centre of education, particularly in the fields of medicine, Scots law, literature, the sciences and engineering. The University of Edinburgh, founded in 1582 and now one of four in the city, was placed 17th in the QS World University Rankings in 2013 and 2014. The city is also famous for the Edinburgh International Festival and the Fringe, the latter being the world's largest annual international arts festival.
Onset and Duration. It takes approximately 15 to 45 minutes for caffeine to reach its peak levels in your bloodstream. Caffeine has a half-life of approximately five to six hours, meaning that it takes this long for its concentration in your bloodstream to reduce by half.
Caffeine is also found in some prescription and non-prescription drugs, including cold, allergy and pain relievers. Caffeine acts as a stimulant by exerting an effect on the central nervous system. The effects of caffeine on the body may begin as early as 15 minutes after ingesting and last up to six hours.hile consuming moderate amounts of caffeine does not seem to have long-term detrimental effects, consuming larger amounts of caffeine (1000 mg or about ten 6-oz cups of coffee a day) on a regular basis may be linked to conception problems, increased episodes of heartburn, and changes in bowel habits.