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.
The health effects of caffeine have been extensively studied. Caffeine competitively inhibits different adenosine receptors, thereby producing mild central nervous system stimulant effects. Short term side effects such as headache, nausea, and anxiety have been shown as symptoms of mild caffeine consumption.