Cardiovascular Effects of Caffeine on Goldfish
By
Lauren Corwin
College Biology I
November 26, 2014
Dr. Michelle Gibson
Introduction
The purpose of this experiment was to understand the effects of caffeine on heart rate using the common goldfish, Carassius gibelio. With the caffeine intake in most American adults being 300 mg (Somogyi, 2009), research in the field of caffeine effects is important. One of the most debated effects of caffeine is the one of which is placed on the circulatory system. To find the cardiovascular effects of caffeine, the common goldfish was placed in 100 g of caffeine diluted in 1000 mL of distilled water. The number of opercular movements was then recorded at a consistent rate resulting in the knowledge…show more content… After 2 minutes, the fish’s respiration rate was at 153, then decreased back down to 150. All of the fish tested followed this pattern. During the first 2 minutes, the opercular movements increased, but at the 4 minute, all of the movements decreased by an average of 3.
Conclusions
These results show that the hypothesis was proven false.The average increase from before the goldfish were put in the caffeine solution to the highest point, the number of opercular movements after 2 minutes, was 21.3 percent, not 15. As shown in Figure 2, the amount of opercular movements was the highest after the 2 minute mark in all of the fish tested.
All of the data was fairly accurate, as all of the numbers were all within reason, but, a few things happened unexpectedly. At the 2 minute mark, all of the fish tested had a decrease in opercular movements. After doing some research, the decrease in movements could be attributed to the idea that some animals develop tolerance to the effects of caffeine after prolonged exposure, which varies by species. (Fredholm, Bättig, Holmén, Nehlig, Zvartau, 1999) This would explain why after the 2 minute mark, the number of opercular movements…show more content… They became more active and almost looked distressed. The increase in activity is likely a result of tachycardia, or a fast heart rate, from caffeine intoxication (Helmenstine, 2014) Problems such as insomnia, anxiety, and an increase in gastric acid (Chambers 2009) occur in humans when too much caffeine is consumed. This could be what caused the goldfish’s behaviors to change after being placed in the caffeine solution.
With every experiment, there are ways to improve. To be even more precise, more fish should have been used. Better techniques to measure the rate of respiration of each fish would also improve the precision of this experiment. The next step to this experiment would be studying the effects of caffeine on other systems in the fish’s body, like the nervous and the excretory system. This would results in more of an understanding of how goldfish react to caffeine in their