Introduction
Caffeine is a component of many common beverages such as coffee, tea, and energy drinks. It operates as a stimulant, and this effect often becomes the subject of studies concerning human physical and mental health and cognitive abilities. The connection between consuming caffeinated beverages and one’s response to exercise is also researched by many scholars. Caffeine may appear in the diets of athletes in many forms and serve as an aid in enhancing one’s performance during training and competing (Graham 2001).
However, caffeinated beverages such as coffee may be less effective in delivering these results in comparison to other substances such as topical gels and pure caffeine (Graham 2001). Nevertheless, all types of these products may have some effect on one’s health and performance.
The range of studies examining the effect caffeine can have on one’s exercising covers different aspects and outcomes of consuming this stimulant. For instance, one study found that daily consumption of caffeine-containing supplements did not have a significant impact on one’s body weight and composition when coupled with intensive aerobic training (Malek et al. 2006). Although prolonged consumption of caffeine was thought to affect the metabolic and hormonal processes of athletes, its influence on people’s bodies was not significant enough to assume such an impact could be viable (Malek et al. 2006). Caffeine also had no notable effect on people’s endurance and force during exercising, although it showed an ability to increase one’s speed of cognitive response (Van Duinen, Lorist, & Zijdewind 2005).
A notable divide between the resting metabolic rates of people consuming caffeine and having an active or a sedentary lifestyle was also not established (Poehlman et al. 1985). Also, insignificant differences in heart rate and blood pressure were found among people who consumed caffeine regularly and occasionally, regardless of their exercise training and experience (Poehlman et al. 1985). Another study confirmed a similar hypothesis investigated possible reasons behind researchers’ initial belief that caffeine can affect one’s exercising performance.
Here, the results showed that caffeine was raising people’s blood pressure regardless of whether they were exercising or resting and thus could not have affected people’s response to physical training (Daniels et al. 1998). Measuring one’s myocardial blood flow and its response to caffeine consumption before exercising and staying in an idle state yielded different results. This study showed that caffeine was able to affect people’s exercise-induced myocardial flow reserve and increase the flow above the average volume (Namdar et al. 2006).
The research regarding the connection between caffeine consumption and one’s response to exercising is replete with studies failing to find any significant effects of the stimulant on people’s vitals. Nevertheless, the process of studying such links remains important as it reveals the impact (or a lack thereof) of caffeine on people’s performance and health. This particular study continues to challenge the idea that caffeine significantly affects people’s well-being.
Aside from measuring people’s pulse rate before and after exercise, it also compares people’s response to caffeine before engaging in any physical activity, thus, revealing the effect of caffeine on the besting body. Two groups of subjects measured their pulse rates at three points in the time mentioned above and performed a simple step test as an exercise for the final part of the experiment (Cooney et al. 2013).
This study aims to establish whether caffeine has an effect on people’s pulse rate before and after exercising and compare it to the changes that happen in people who did not consume caffeine before physical activity. The central hypothesis states that there will be a visible difference between the pulse rates of two subject groups before and after exercising, proving that caffeine has a significant impact on one’s blood flow.
Methods
Refer to the School of Life and Environmental Sciences (2018).
Results
The study analyzed the results of two groups where one of them consumed a caffeinated beverage (group A), and the other consumed a decaffeinated beverage (group B). The former group of participants consisted of 57 individuals, while the latter had 49 individuals. The heart rate of both groups was measured at three points – before and after consuming the beverage and after exercising. All estimations of the pulse rates were documented in the form of beats per minute.
The mean (± SE) pulse rate of the first group was 76.1 ± 2 bpm pre-treatment, 78.4 ± 1.9 bpm after drinking the caffeinated beverage and further rose to 124.8 ± 3.6 bpm after physical activity (Figure 1). The documented mean (± SE) pulse rates of the group that consumed a decaffeinated drink were 79 ± 1.9 bpm pre-treatment, 79.3 ± 1.9 bpm post-treatment, and 127.7 ± 4 bpm post-exercise (Figure 1).
A two-way Analysis of Variance (ANOVA) was conducted after collecting and assessing raw data to establish or eliminate the possibility of notable divergences between the results of the two groups (Table 1; Table 2). There was no significant difference in the mean pulse rate between subjects who consumed caffeinated coffee and those who consumed decaffeinated coffee (ANOVA: F(1, 312) = 0.09, p > 0.05). Across all coffee treatment groups, the mean pulse rate at pre-treatment was significantly different to that at post-exercise (ANOVA: F(2, 312) = 211.50, p < 0.0001; Tukey’s multiple comparisons: p < 0.0001) and the mean pulse rate at post-treatment was significantly different to that at post-exercise (ANOVA: F(2, 312) = 211.50, p < 0.0001; Tukey’s multiple comparisons: p < 0.0001).
Discussion
The insignificant increase in the pulse rate of people before and after consuming a caffeinated and a decaffeinated beverage indicates that caffeine does not have a notable effect on people’s blood flow. Both groups experienced a small change in their pulse rate, which may imply a presence of a placebo effect or a natural fluctuation of pulse rates due to anxiety related to the experiment or other unrelated reasons. This finding does not correspond with the results of other studies that noted a rather significant alteration of people’s blood flow in an idle state (Namdar et al. 2006). However, some studies’ outcomes correspond with the result of this research and confirm a lack of impact of caffeine on one’s pulse rate, blood pressure, and other processes (Graham 2001; Poehlman et al. 1985).
Another type of result is the change of the pulse rates before and after exercise. Here, the numbers in both groups increased significantly, which indicates the effect that physical activity has on people’s bodies (Duncker & Bache 2008). According to the final calculations, the insignificant difference in the mean rates shows that caffeine does not have a substantial impact on people’s pulse. This finding also supports previous studies which do not find a correlation between caffeine and altered body responses to exercising (Daniels et al. 1998; Malek et al. 2006; Van Duinen, Lorist, & Zijdewind 2005).
It should be noted that this experiment considers a single event of consuming caffeine. Moreover, it features a rather simple exercise (Cooney et al. 2013). The third limitation of the study is that it does not feature long-term outcomes of continuous caffeine use or athlete-level training. Thus, the methodology can be improved by broadening the range of participants, including prolonged studies of regular caffeine consumption, and using different exercises to confirm the results.
The results of the experiment do not confirm the original hypothesis and show that caffeine does not have a significant impact on people’s pulse rate before and after exercising. The results of the two participating groups do not have any significant differences that could indicate that caffeinated substances can disturb the body’s processes and change its response to physical activity. This study supports the existing scope of research is confirming the insignificant effect of caffeine on exercising.
Reference List
Cooney, JK, Moore, JP, Ahmad, YA, Jones, JG, Lemmey, AB, Casanova, F, Maddison, P, & Thom, JM 2013, ‘A simple step test to estimate cardio-respiratory fitness levels of rheumatoid arthritis patients in a clinical setting’, International Journal of Rheumatology, vol. 2013, no. 174541, pp. 1-8.
Daniels, JW, Molé, PA, Shaffrath, JD, & Stebbins, CL 1998, ‘Effects of caffeine on blood pressure, heart rate, and forearm blood flow during dynamic leg exercise’, Journal of Applied Physiology, vol. 85, no. 1, pp. 154-159.
Duncker, DJ & Bache, RJ 2008, ‘Regulation of coronary blood flow during exercise’, Physiological Reviews, vol. 88, no. 3, pp. 1009-1086.
Graham, TE 2001, ‘Caffeine and exercise: metabolism, endurance and performance’, Sports Medicine, vol. 31, no. 11, pp. 785-807.
Malek, MH, Housh, TJ, Coburn, JW, Beck, TW, Schmidt, RJ, Housh, DJ, & Johnson, GO 2006, ‘Effects of eight weeks of caffeine supplementation and endurance training on aerobic fitness and body composition’, Journal of Strength and Conditioning Research, vol. 20, no. 4, pp. 751-755.
Namdar, M, Koepfli, P, Grathwohl, R, Siegrist, PT, Klainguti, M, Schepis, T, Delaloye, R, Wyss, CA, Fleischmann, SP, Gaemperli, O, & Kaufmann, PA 2006, ‘Caffeine decreases exercise-induced myocardial flow reserve’, Journal of the American College of Cardiology, vol. 47, no. 2, pp. 405-410.
Poehlman, ET, Despres, JP, Bessette, H, Fontaine, E, Tremblay, A, & Bouchard, C 1985, ‘Influence of caffeine on the resting metabolic rate of exercise-trained and inactive subjects’, Medicine and Science in Sports and Exercise, vol. 17, no. 6, pp. 689-694.
School of Life and Environmental Sciences 2018, Data collection for scientific report (BIOL1008 only), The University of Sydney, Sydney.
Van Duinen, H, Lorist, MM, & Zijdewind, I 2005, ‘The effect of caffeine on cognitive task performance and motor fatigue’, Psychopharmacology, vol. 180, no. 3, pp. 539-547.
Appendix
Table 1: Two-Way Analysis of Variance Testing the Effect of Caffeine on Mean Pulse Rate.
Table 2: Tukey’s Multiple Comparisons Test for Significant Differences in the Mean Pulse Rate at Pre-Treatment, Post-Treatment and Post-Exercise Times.