AbstractIntroductionMethodResultsDiscussionBibliographyDoes the intake of caffeine affect your heart rate?Bhavi Patel 3/8/12AbstractPrevious research has shown that the intake of caffeine has an effect on the pulse rate of human beings. Therefore, in this lab, we had 10 of the subjects drink one cup of coffee and 10 subjects that did not. Then we took the pulse rate of each subject after five minutes for one hour and thirty minutes to see if the intake of caffeine had any effect on pulse rate. Our results further proved that the intake of caffeine indeed has an effect on pulse rate. IntroductionWhat is coffee? Coffee is a brewed beverage with a dark, acidic flavor prepared from the roasted seeds of the coffee plant…Coffee can have a stimulating effect on humans due to its caffeine content (Wikipedia). How does caffeine affect the human body? Caffeine blocks adenosine, a neurotransmitter that normally causes a calming effect in the body. This blockage causes the adrenal glands to release adrenaline, causing your heart rate to increases, your pupils to dilate, your muscles to tighten up, and glucose to release into your blood stream for extra energy (Over caffeinated). My lab group wanted to see whether or not the intake of caffeine really has an effect on pulse rate. With this information my lab group hypothesized that if caffeine is consumed, then the pulse rate would increase and thiswould mean that the intake of caffeine has an effect on heart rate. Method First take every one’s pulse rate (per min) for an initial count. Then have 10 subjects drink one cup of Dunkin Dounts’ coffee and have the other 10 subjects drink nothing. After the intake of coffee take the pulse rate of all the subjects after every five minutes for one hour and half. Then record and organize your data and conduct a t-test and an f-test. ResultsAfter getting all the data from all 20 subjects, we figured out the average, the variance, the standard deviation, the standard error, and the change in heart rate for each subject in both thecontrol group, the subjects that did not drink coffee and the experimental group, the group thatdid drink coffee. Table 1: Shows the average, variance, standard deviation, standard error, and delta heart rate for the caffeine groupSubject A B C D E F G H I J KAverage 81.263 60 78.32 86.53 74.32 80.63 74.11 76.84 60.63 80.42 71.16Variance 186.76 26.667 18.34 53.71 25.01 16.47 94.88 6.363 2.246 40.7 41.92St. Dev 13.666 5.164 4.282 7.329 5.001 4.058 9.74 2.522 1.499 6.38 6.474St. Error 3.1352 1.1847 0.982 1.681 1.147 0.931 2.235 0.579 0.344 1.464 1.485Delta HR 48 16 16 20 16 20 32 8 4 20 20Table 2: Shows the average, variance, standard deviation, standard error, and delta heart rate for the non-caffeine groupSubject A B C D E F G H I J KAverage 72.211 80.211 69.89 72.21 64.42 63.37 66.11 89.89 81.68 76.21 70.32Variance 4.3977 16.842 11.32 29.29 10.48 21.8 20.21 4.211 13.01 0.842 16.56St. Dev 2.0971 4.1039 3.365 5.412 3.237 4.669 4.496 2.052 3.606 0.918 4.07St. Error 0.4811 0.9415 0.772 1.242 0.743 1.071 1.031 0.471 0.827 0.211 0.934Delta HR 12 16 12 20 8 16 20 4 12 4 16Table 3: Shows the difference in heart rate between the two groups. The red bar is the experimental group and the blue bar is the control group. Since the red bar is larger than the blue bar, this means that there is a greater change in heart rate in the experimental group.051015202512.72720.00Chart Title Control Group Experimental GroupDelta HRThen we conducted a two –tailed t-test and an f-test to further analyze our data. For our f-test we got a p-value of .0287 and for our two-tailed t-test we got a p-value of 0.073.DiscussionOverall the data supported our original hypothesis that the intake of caffeine would increase heart rate, according to table 3, we could see that there is a significant amount of difference between the changes in heart rate between the two groups. And since the experimental group has a greater difference than the control group this shows that caffeine plays a role in effecting heart rate and therefore the information obtained from over caffeinated was correct. In addition to this, when we conducted an f-test, we found out that our data had a p-value of 0.0287 by comparing the delta HR of the two groups for variance. This means that since the p-value is less than 0.05 we reject the null hypothesis that says that if caffeine is consumed, then the heart rate is not increased. In addition to this, the f-test showed that there is no equal variance between the two groups. The t-test we used was two tailed because the data looks likecaffeine intake raises heart rate for some people and lowers for others. With this information, we got a p-value of 0.0783 using a two tailed t –test, this suggests that we reject the null hypothesis since the p-value is less than 0.05. The results of a 2-tailed equal t-test suggest that caffeine intake does increase heart rate because the p-value of 0.073 is very low.When we looked back at our data, we realized that there may have been an issue with the heartrate because we did not wait for a half hour to an hour after we got to the lab and therefore each subject’s heart beat could have been faster than normal since they may have walked to thelocation of the lab room. This could cause an increase in heart rate and the initial may have not been the normal heart rate. Bibliography"Coffee." Wikipedia. Wikimedia Foundation, 03 Aug. 2012. Web. 07 Mar. 2012. <http://en.wikipedia.org/wiki/Coffee>."Over Caffeinated." Caffeine. OverCaffeinated.org, 2006. Web. 08 Mar. 2012.