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.
Dietary sources include coffee, tea, cola drinks, and chocolate, as well as energy drinks. The most notable behavioral effects of caffeine occur after consumption of low-to-moderate doses (50-300 mg) and include increased alertness, energy, and ability to concentrate.