The effects of caffeine on blood pressure, heart rate, cognitive function and reaction times in collegial level athletes.
Background: Caffeine is the world’s most commonly consumed psychoactive drug. Caffeine acts mainly via antagonism of adenosine receptors and by doing this caffeine prevents the slowing effect adenosine has on neural activity. It can also exert powerful effects at low doses including: enhancing performance, cognitive ability and upregulation of lipolysis and glycogen resynthesis. Less than two decades ago the drug was removed from the list of banned substances by the IOC, with this and its ability to enhance performance, caffeine is being used more frequently in sport. Objectives: this study will investigate the effects of caffeine on cardiovascular parameters, cognitive function and reaction times with secondary focuses on differences in sport and gender. Methods: 30 participants were recruited, 5 were excluded. The remaining 25 refrained from caffeine for 12 hours prior to each of the two sessions. A consent form was signed and a lifestyle questionnaire was also filled in. Both sessions each participant attended followed the same format: blood pressure and heart rate were taken, a reaction time test was done and then a stroop test was completed. From here the participant consumed either a caffeinated or decaffeinated beverage and then sat unstimulated for 45 minutes. Participants then repeated all tests again. They returned a week later and repeated this process once more. Results: Caffeine was responsible for an increased SBP and DBP but a decrease in HR, the decaffeinated beverage contributed to a decrease of all 3 measurements. Data concerning SBP between genders post caffeine administration returned a significant p value of P= 0.01. The results of the stroop test showed improvement with both the caffeinated beverage and decaffeinated – time for both data sets showed decreasing trends as well as the number of errors made. Reaction times consistently decreased in reference to all athletes. Independent t-tests showed post caffeinated data between male and female had a significant p value of P = 0.01. Conclusion: Overall, caffeine increased blood pressure and decreased heart rate. It contributed to decreased times and number of errors made therefore improved performance in the stroop test. Caffeine also showed a trend of decreasing reaction time tests. Between the sub groups although there were some significant results observed, trends were hard to identify. Further research on a larger sample of would may be more likely to identify definitive trends between gender and sports. Key words: Caffeine, Exercise, Cognitive Function, Reaction Time, Blood Pressure, Gender