The Effect of Caffeine on Swimming speed (Health, Medicine, Nursing Article)

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Introduction
With various kinds of drugs in the world, caffeine is known as one of the most popular drugs. Caffeine had been consumed since ancient times by people of different races. It has been used as an ingredient in foods and beverages such as in chocolate, soda, coffee, sports drink, and black and green tea. It can also be found in some over-the-counter medications such as Excedrin, Anacin, and Midol.
When consumed, caffeine can alter some physiologic functions of an individual. These changes include the stimulation of the central nervous system, the elevation of both heart rate and blood pressure, lowered levels of fatigue, and increased alertness (Astorino et al., 2007). A caffeine moderate intake of about 100-300 milligrams daily is considered safe for healthy adults (Williams, 2007). However, tremors, restlessness, and insomnia are known effects of acute intake of caffeine (Archna and Jaspal, 2008; Williams, 2007).
Caffeine had also been used in sports and during training by coaches, athletes, and recreational athletes for performance to improve. It is said to have beneficial effects during both aerobic and anaerobic exercises. According to Forman et al. (1995), caffeine is used by approximately about 70% of young athletes globally. Studies showed an improved sports performance of around 3 mg/kg of caffeine (Jenkins et al., 2008; Ivy et al., 1979; Kovacs et al., 1998; Bridge and Jones, 2006).
The explanation for caffeine’s ergogenic effect and its mechanism is still unclear. Caffeine intake is also associated with increased secretion of epinephrine (Graham et al., 1995; Greer et al., 1998). Researchers also suggested the effects of caffeine on endurance activities. Caffeine increases the use of fats while muscle glycogen is spared (Costill et al., 1978). However, this was argued by Graham et al. (2000) claiming that fat metabolism does not increase with caffeine. In another study, Kalmar and Cafarelli (1999) stated the mechanism of action of caffeine on strength exercises. Performance when doing strength exercises is enhanced since the firing rates of motor units are increased which would then lead to an increase in force production.
Several studies explored the ergogenic effect of caffeine supplementation when doing any physical activity or exercise in terms of sports performance. Caffeine showed beneficial effects on aerobic exercises as reported by the majority of the studies conducted. This claim was supported by Costill et al. (1978) wherein caffeine (330 mg) was found to significantly improve the cycle ergometer exercise time to exhaustion by 20%. In addition to this, a study conducted by Ivy et al. (1979) reported that the mean power output of cycling in two hours was enhanced significantly upon intake of caffeine (250mg). This result was 7.4% higher as compared with the placebo. Other findings of MacIntosh and Wright (1995) demonstrated in a 1500 m freestyle race an improved swimming time due to caffeine ingestion. Based on the results of these studies, it can be carefully concluded that caffeine enhances performance during endurance exercises.
The improvement of caffeine intake seen in sports performance is not just exclusive to aerobic exercises. Athletes, such as short-distance swimmers, who utilize the anaerobic system are interested in taking supplementation to boost their strength. Some studies indicate that caffeine can enhance performance on anaerobic exercises. Jacobson et al. (1992) found out that in highly trained males, caffeine intake (7 mg/kg) considerably improved their maximal strength. However, Bond et al. (1986) findings showed no significant difference in the muscular strength of untrained males between caffeine ingestion and placebo. A study by Beck et al. (2006) suggested that supplements that contain caffeine may be effective for increasing upper body strength but not for the lower body. Due to these varying results, a gap in the scientific literature exists regarding the effect of caffeine on anaerobic performance. There are only a few studies conducted concerning this gap. Moreover, the evidence available is inconclusive due to conflicting results. Based on this reason, this study is conducted to explore further the role of caffeine in strength enhancement particularly in swimmers. The purpose of this study is to examine the effects of caffeine supplementation (5 mg/kg) on swimming speed in college students. It is hypothesized that there will be a significant improvement in swimming time with supplementation of 5 mg/kg of pharmaceutical-grade caffeine.
METHODOLOGY
Study Design
The study design is a randomized double-blind cross-over. This study involves an initial visit and two testing sessions. During the initial visit, investigators measured the baseline for height and body mass of the subjects. During the first and second testing sessions, subjects were given either caffeine supplementation ...