Actions of caffeine in the brain with special reference to factors that contribute to its widespread use. Pharmacol Rev. Lipid content and composition of coffee brews prepared by different methods. Food Chem Toxicol. Tocopherols in coffee brews: influence of coffee species, roast degree and brewing procedure.
Pytother Res. Article Google Scholar. Effects of caffeine ingestion on metabolism and exercise performance. Med Sci Sports Exer. CAS Google Scholar. International society of sports nutrition position stand: caffeine and performance. J Int Soc Sports Nutr. Coffee acutely increases sympathetic nerve activity and blood pressure independently of caffeine content.
Article PubMed Google Scholar. Doherty M, Smith PM. Effects of caffeine on ingestion of exercise testing: a meta-analysis. Effect of caffeine on sport-specific endurance performance: a systematic review. J Strength Cond Res. Dicinnamoylquinides in roasted coffee inhibit the human adenosine transporter. Eur J Pharmacol. Failure of caffeine to affect substrate utilization during prolonged running. Med Sci Sports Exerc. Effect of nutritionally enriched coffee consumption on aerobic and anaerobic exercise performance.
PubMed Google Scholar. A new validated endurance performance test. Reliability of time-to-exhaustion versus time-trial running tests in runners. Effects of time-release containing supplement on metabolic rate, glycerol concentration, and performance.
J Sports Sci Med. Validity and reliability of a scale to assess fatigue. Psychiatry Res. Performance changes in NBA basketball players vary in starters vs nonstarters over a competitive season. Resistance exercise may improve spatial awareness and visual reaction in older adults. Cohen, J. Statistical power analysis for the behavioral sciences, 2 nd ed. Hillsdale, New Jersey: Erlbaum; Methods for controlling type I error across multiple hypothesis tests. Using SPSS for windows: analyzing and understanding data.
New Jersey: Prentice-Hall; Google Scholar. Caffeine ingestion does not alter carbohydrate or fat metabolism in human skeletal muscle during exercise. J Physiol. Metabolic, catecholamine, and exercise performance responses to various doses of caffeine. Eur J Clin Pharmacol. The influence of a CYP1A2 polymorphism on the ergogenic effects on caffeine. Effects of caffeine, sleep loss, and stress on cognitive performance and mood during us navy seal training. Psychopharmacology Berl. Smith AP. Caffeine at work.
Hum Psychopharmacol. An investigation of the effects of coffee on alertness and performance during the day and night. Slow-release caffeine: a new response to the effects of a limited sleep deprivation. Caffeine or melatonin effects on sleep and sleepiness after rapid eastward trans meridian travel. Recovery after prolonged sleep deprivation: residual effects of slow-release caffeine on recovery sleep, sleepiness and cognitive functions.
Effect of chronic caffeine intake on choice reaction time, mood, and visual vigilance. Physiol Behav. Trice I, Haymes EM.
Effects of caffeine ingestion on exercise-induced changes during high-intensity, intermittent exercise. Int J Sport Nutr. Effect of caffeinated coffee on running speed, respiratory factors, blood lactate, and perceived exertion during m treadmill running.
Br J Sports Med. Caffeine, cycling performance, and exogenous CHO oxidation: a dose—response study. Coffee blunts mental stress-induced blood pressure increase in habitual but not in nonhabitual coffee drinkers. Download references. The authors would like to thank Elite Turkish Coffee Strauss Coffee, Lod, Israel for providing the funding and supplying the product for this study.
David D. Church, Jay R. Hoffman, Michael B. LaMonica, Joshua J. Riffe, Mattan W. Hoffman, Kayla M. Baker, Alyssa N. Varanoske, Adam J. Wells, David H. The positive effects of caffeine on alertness and reaction time have been studied extensively and an overview of these studies can be found in the EFSA evaluation 1. Thus, it appears that interval timing and reaction time performance are not always necessarily interdependent The latter two studies point to the potential impact of caffeine consumption on performance and safety.
Caffeine is often consumed shortly after waking up to help increase alertness and fight sleep inertia. Finally, the efficacy of drinking coffee versus napping to aid night-time highway driving has been compared. Data from the aforementioned studies suggests that caffeine may help as an effective countermeasure to the performance decrements induced by sleep-deprivation, particularly when there is no opportunity to take a nap.
It does this by attaching to the same spot on nerve cells used to detect adenosine these spots are called adenosine receptors. Because adenosine is what your brain uses to reduce and stabilize nerve activity, suddenly all of the brain cells become hyperactive.
This effect causes the pituitary to release adrenaline it thinks that all the activity means there is an emergency , which leads to the responses I mentioned above. Reaction time is essentially defined as the time taken for a stimulus to be picked up by the receptors in the body and the response to be carried out by the central nervous system as a result of the stimulus.
Electrical impulses travel from the sensory neurones to the motor neurones. These signals travel through junctions called synapses between the ends of neurones by transmitting chemicals and diffusing through the gaps.
This however, may cause some to be confused with reflexes. Reflexes, unlike reactions, are involuntary actions used to protect the body. The principle of the experiment was to examine why certain drinks affected reaction time more than others, and what their particular effects are.
With our particular interests in sports, we wanted to incorporate our passion into the fields of science. To find out which drink is the most effective in reducing reaction time, and why. We tested this by measuring our reaction times using a reaction time data logger which was connected to a computer after having consumed ml of the drink, with a time interval between 0 minutes to 10 minutes.
The reaction time data logger involved pressing a button as soon as the symbol on a computer screen turned from white to yellow, and the time taken between the colour turning yellow and you pressing the button determines your reaction time.
We repeated this procedure 10 times, giving 10 readings and then averaged to give the mean result, as to increase the reliability of the results. The colour change was controlled by a different person, ensuring that the subject could not predict the next colour change. As I mentioned earlier, the repetition was necessary for reliability and we averaged the readings to evaluate whether the results correlated to the mean.
This also allowed us to identify an possible anomalies. Hence, it is plausible to conclude that the results are reliable if they are more or less similar to each other. Results can vary for each subject so we measured a control for each person by conducting the experiment having only just drunk water and no other liquids beforehand.
To further evaluate and prove the effects of the drinks on reaction times, we used a second experiment which involved one person dropping a 30cm ruler at eye level and the subject catching it as fast as possible. We made sure that the 0cm mark was at the bottom and that the 30cm mark was at the top. The subject would then catch the ruler with his index finger and thumb only.
We measured the length at which the subject caught the ruler, and repeated this procedure three times to increase the reliability.
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