Materials and Methods~

Research Question: How does caffeine affect your heart rate?

Materials needed:

One caffeinated beverage will be drank by each person each day for 3 weeks. After each week is over the drink will be switched out for another and a total of three different beverages will be consumed. Among these are coffee, soda, and tea. The brand of coffee that was chosen to be used is Maxwell House; For the soda it was Coca-Cola; And for the tea, Lipton Pure Leaf was used. One standard 8-ounce mug of coffee will be consumed; One 12-ounce can of Coca-Cola; And one 18.5-ounce bottle of Lipton Pure Leaf Iced Tea. Also a timer will be needed for measuring heart rate.

Caffeine Content

The caffeine content is obviously going to be different for each of these three beverages. As far as the coffee goes, its hard to tell exactly how much caffeine is in a cup becuase, unlike some other caffeinated drinks, the caffeine is in the coffee beans naturally instead of added in during processing. However, it is estimated that coffee contains about 115 to 175 milligrams of caffeine per cup, but that depends on the strength of the coffee. Coke is easier to measure as an exact amount of caffeine is added in during processing, and it contains about 35 milligrams per 12-ounce serving. Lipton Pure Leaf tea also contains about 57 milligrams of caffeine. But, does the difference in caffeine content change the affect it has on your heart rate? Through this experiment the answer will be found, as well as how caffeine affects your heart rate in general.

Measuring Heart Rate:

Three different heart rate measurments will be taken each day, and each of the measurements will be takin within a 3-hour period. The first measurement is taken before any caffeine has been consumed; The measurements will be taken by using the old fashion method of placing two fingers on your wrist, setting a timer for one minute, and counting the beats until the time is up. This will give the heart's beats per minute (BPM).

The beverage will be drank about 20 minutes after the first measurement, giving the caffeine about 40 minutes to kick in (about the average) before the second measurement is taken. Then, about an hour after the second measurement, giving the caffeine a little time to wear off, the third and final measurement is taken.

From these measurements one will be able to see the average heart rate when there is no caffeine in the system, the likely spike after the caffeine has been given just enough time to make its way into the system, and finally the likely "crash" afterward, and from that see how much caffeine can really have an affect on your heart rate.