New app tells you whether or not it's a good idea on caffeine effect

A new smartphone app, developed by researchers at Penn State in the US, graphs caffeine's effect on your body throughout the course of the day, so you'll know if that afternoon cuppa will keep you awake at night.

To plot caffeine's effect with the app, dubbed Caffeine Zone 2, type in information about how much caffeine you drank (coffee, tea, soda, etc.), or plan to drink, and when you plan to have a caffeinated beverage and how fast you plan to drink it.

After you make your selections, the app generates a line chart of your predicted caffeine levels for the next 24 hours -- such as whether or not your caffeine level will make you feel mentally alert or if it will cause problems with your sleep. The values are adjustable based on individual differences, such as weight, according to a press release last week.

"Many people don't understand how caffeine levels in their bloodstream go up and how they go down," researcher and professor Frank Ritter told health website Science Daily in an article on Tuesday. "It's important to understand the effect that caffeine can have at these various levels."

Ritter adds that if you drink a cup of coffee quickly, for example, you'll experience a spike in mental alertness, but enough caffeine can linger in your bloodstream to keep you awake at night.

Both a free version of Caffeine Zone 2 (with ads) and a paid ad-free version ($0.99) are available for the iPhone, iPod Touch and iPad.

An app for Android users that tracks your caffeine intake is Caffeine Tracker, which records the amount of caffeine you consume and "accounts for the natural metabolism" of the caffeine in each drink over time. The caffeine metabolism algorithm takes into account factors such as your weight, whether or not you are pregnant, and if you use oral contraceptives, for example.

For other daily addictions, smokers can check out apps such as Cigarettes Tracker by GigiApps or TobaccoQuitter to keep tabs on your daily cigarette count, craving history, and even financial costs. For alcoholic beverages, you can rely on apps such as AlcoDroid to track your daily drinks and calculate your blood alcohol content.