1 OPINION. 2  The screening process for Syrian refugees is much more rigorous than for other visitors coming to the U.S. (AP Photo/Hassan Ammar)
About 250 milligrams of caffeine â or the equivalent of 2 to 2 1/2 cups (473 to 591 milliliters) of plain, brewed coffee â a day may cause this effect. If you have type 2 diabetes and you're struggling to control your blood sugar levels, limiting the amount of caffeine in your diet may provide a benefit.
Sugar crashes, energy slumps and caffeine withdrawal. According to the infographic, caffeine enters the bloodstream within 10 minutes of consuming an energy drink, triggering a rise in heart rate and blood pressure. Over the next 15-45 minutes, caffeine levels in the bloodstream peak.