Have you been sipping too much coffee lately? Well, your iPhone could now help you keep tabs on just how much caffeine enters your body. Called the Caffeine Zone, this free iOS application was developed by two doctors at the Penn State University, Frank E. Ritter and Kuo-Chuan Yeh. Keeping a wary eye on the amount of caffeine in your blood, the application advises you on the optimum time to down a cuppa and tells you just when to stop. This makes sure you don’t keep awake at times when you should be sound asleep, due to over intake of coffee or tea. Also, as per studies conducted by the developers of the app, 200 and 400 milligrams (mg) of caffeine in a person’s bloodstream is optimum for a good amount of mental alertness, while below a 100mg is bound to leave you drowsy.