Caffeine Experiment Research Paper

However, our prediction that caffeine consumption is a factor responsible increasing respiration rate and pulse rate was not observed but rather, results imply that caffeine does not have a visible effect on short-term exercise performance. Therefore, the alternate hypotheses are rejected in favour of the null. is This may be because caffeine only has a positive effect in prolonged, intense exercise that last up to 2 hours (Hogervorst 2008). As respiratory rate and pulse rate are just simple measures of exercise performance, the experiment does not accurately determine whether caffeine ingestion increases power (force of muscles), or endurance (time rate) of exercise performance. Furthermore, in parallel with Kalmar & Cafarelli’s (1999) study,

when exercise of shorter duration are examined, the results are more inconsistent and no significant differences in short-term exercise performance.
Various studies prior have found that subjects in the caffeinated condition with a higher muscle mass had a greater increase in pulse rate after aerobic exercise than subjects with a lower muscle mass (Woolf et al.

2008). In other words, there is an interaction between caffeine intake and muscle mass that determines pulse rate and in this experiment, muscle mass was a variable that was not accounted for. Furthermore, the resting pulse rate response to caffeine consumption prior to exercise is considered one of the most variable parameters of those in the study. Because this experiment measured resting pulse rate less than one hour before exercise, it is not completely reliable as a study by Bailey (1989) similarly suggested the implications of pulse rate variability to be a factor of the fluctuating results across subjects despite

having a much longer resting pulse rate measurement (3-4 hours). However due to the time restriction of the experiment, a longer resting period was unable to be implemented. Previous literature studies into caffeine effects on exercise involved an 8-week longitudinal study with specifically all male or female subjects of similar body mass and age, implementing a daily structured diet and exercise. These controlled variables vastly aid in a more accurate result as caffeine sensitivity and body mass may be large factors influencing pulse and respiratory rate before and after caffeine ingestion (Malek et al. 2006). A more accurate method may be to measure heart rate using an electrocardiography machine (ECG) to specifically measure the R-R intervals (time interval between sequential heart beats) and to observe changes in heart rhythm for further analysis of their possible link to caffeine ingestion.
There were similarly no significant differences in respiratory rate between the two coffee conditions, meaning levels of carbon dioxide in cells and tissues that need to be expired are not directly affected by caffeine.

Previous studies on the effects of caffeine on aerobic and anaerobic exercise have revealed elevated blood pressure at fatigue in the caffeine condition compared to the placebo condition, which translates to cells requiring more oxygen thus higher respiration rates required for oxygen uptake (Bailey 1989). Controversially, a study on habitual caffeine ingestion responses to exercise have found that subjects in the habitual coffee condition had reduced respiratory rate during exercise compared to the placebo condition. However this may mean that habitual caffeine intake decreases the body’s sensitivity to caffeine thus have no effect on exercise. In this experiment, subjects were required to be daily coffee drinkers so the concept of caffeine desensitivity could be an explanation for the similar measurements in respiratory rate in both conditions (Bangsbo et al.

1992).
Amounts of daily caffeine intake and diet were not controlled and compliance to caffeine consumption for a specific period of time was not ensured. Other factors such as rest, prior exercise, and over-the-counter medications may have affected each subject’s response and sensitivity to caffeine. In addition, subjects in this study ranged from high to low caffeine consumers which may have contributed to the study results. Different doses of caffeine should therefore be examined to ensure subjects have not grown a tolerance to the amount of caffeine provided in the experiment (Woolf et al. 2008). Thus, future research that compares the effect of caffeine in habituated caffeine consumers and low caffeine consumers in aerobic exercise performance. Despite previous literature having shown the implications of caffeine as an ergogenic substance via its antagonistic effects on adenosine receptors and stimulation of calcium ions on exercise performance, no increase in respiratory rate or pulse rate was observed in this study thus our null is accepted and ergogenic properties of caffeine cannot be assumed.