Caffeinated drinks such as coffee and soda are the pick-me-ups of choice for many people, but too much caffeine can cause nervousness and sleep problems. Caffeine Zone, a new software app developed by researchers, can help people determine when caffeine may give them a mental boost and when it could hurt their sleep patterns. The software takes information on caffeine use and integrates it with information on the effects of caffeine to produce a graph of how the caffeine will affect the users over time.