How Different Stimulants Enhance Sports Performance to Give an Athlete a Competitive Advantage

The use of substances by athletes to improve performance has been a feature of competition since the ancient times. Athletes took these substances to improve strength and overcome fatigue, with this practice continuing to this very day. Today in numerous sports these performance-enhancing substances have become even more present. Some common examples of these substances are; steroids, erythropoietin, human growth hormone, and stimulants. This essay will focus on stimulants. Stimulants have been used long ago in competition, for example, Thomas Hicks won the 1904 Olympic marathon after taking a combination of stimulants (strychnine and brandy) [1]. However, the use of stimulants to enhance performance can have adverse effects on health. For instance, Tommy Simpson collapsed and died during the 1967 Tour de France.

The stimulants he was taking (alcohol and amphetamine) was partly blamed for his death [1]. Since then, stimulants have featured on the prohibited list and the use of stimulants during competition has been banned [2]. Regardless, stimulants, whether it is legal or illegal, are constantly still taken by athletes because they want to boost their performance to gain an advantage over others in order to win. Research has shown the reason for the athlete ’s competitive gain is primarily due to stimulants increasing alertness, anaerobic performance, endurance and decreasing fatigue [3].

Therefore, this essay will review the literature to see how different stimulants (i.e. amphetamine, ephedrine, caffeine, and cocaine) enhances sports performance to give an athlete a competitive advantage. Amphetamine Amphetamines were first synthesized in 1920 and were heavily used during the second world war to increase alertness and fatigue [4]. It stimulates the central nervous system (CNS) and causes the release of noradrenaline from the sympathetic nerves by mirroring sympathetic neural activity, as well as discharging dopamine from the brain [5]. So, amphetamines cause a surge in these neurotransmitters (dopamine and noradrenaline), resulting in physiological consequences, such as an increase in heart rate and blood flow to muscles [1]. Proposing the possibility that amphetamines can enhance sports performance because of its stimulatory effects. Evidently, a paper by Gene et al. [6] supports this, as it reveals that amphetamine significantly improved performance and athletes felt that this stimulant-enhanced their strength, coordination, and endurance.

To add, Avis et al. [7] shows the positive effect of amphetamines include higher levels of physical energy and mental aptitude, along with those who consume them feeling more confident and efficient. Additionally, in a randomized cycling cross-over trial at different RPE (hard or very hard) intensities, amphetamines enabled participants to endure higher work rates and levels of metabolic and cardio-respiratory for longer, while they perceived the exercise not to be that hard even when working at an RPE representing very hard [8]. Illustrating, exercise is prolonged by a stimulant acting on the CNS [8]. Indicating, that this stimulant is an ergogenic aid for performance. However, the continued use of this stimulant can have adverse effects on health. For instance, the side effects associated with amphetamines are confusion, palpitations, rapid breathing, hypertension, tachycardia and tremors [9]. Ephedrine Ephedrine is the purified form of an ephedra alkaloid, is a sympathomimetic amine known for its stimulant properties [10]. These include acting as a CNS stimulant and stimulating alpha and beta-adrenergic receptors [7]. Besides, this type of stimulant has been shown to help with sports performance and weight loss [4]. For this reason, they are used by athletes. With respect to weight loss, Shekelle et al. [11], meta-analysis reveals that ephedrine can promote moderate weight loss for up to 6 months, but there was no data about long-term weight loss.

Regarding performance, a double-blind crossover study investigating the effect 24 mg of ephedrine has upon physical performance, reports ephedrine indeed influences blood pressure and exercise and recovery heart rates, yet it did not improve any of the measures for physical work (strength, endurance, and power) [12]. On the other hand, Bell et al. [13] study findings disclose ephedrine significantly improved power output during the early phase of a cycle test (Wingate). Another study by Bell et al. [14] displays that a dose of 0.8 mg/kg ephedrine improved the running times of 12 athletes in a 10km run from 46.9 ± 3.3 minutes to 45.5 ± 2.9 minutes. These results indicate that this stimulant can be used as an ergogenic aid for prolonged exercise such as long-distance running.

The possible ergogenic effect exhibited by ephedrine could be because of this stimulant increasing the release of monoamines such as dopamine centrally and peripherally [10]. Caffeine Caffeine is consumed in a variety of forms and enjoyed by millions of people, including athletes. The effect of caffeine is to reduce fatigue, increase alertness and wakefulness [15]. Research has demonstrated that low to moderate doses of caffeine (3 to 9 mg/kg) has a significant impact on exercise performance [16,17]. This is further supported by a double-blind crossover study [18]. The study found that different quantities of caffeine consumed enhanced the performance of fifteen triathletes and cyclists during a 1-hour cycling time trial. Also, a meta-analysis by Doherty and Smith [19], quantified the effect caffeine had on different exercise protocols (short-term, high-intensity exercise and time to exhaustion). They report that caffeine has an impact on whole body exercise and has a greater effect on the time to exhaustion protocol (effect size = 0.63) compared to the short-term protocol (effect size = 0.16). In all, the ingestion of caffeine has been found to raise an individual’s endurance levels [20]. Suggesting, athletes use caffeine due to its reported ergogenic benefits. The supposed beneficial effects of caffeine on performance can be attributed to it exerting its effect through intracellular free fatty acid oxidation and serving as an adenosine receptor antagonist in the CNS [21].

Though, the influence it has on performance is probably due to its role as an adenosine receptor antagonist [9]. In other words, caffeine ’s advantageous effect on performance is a result of it directly affecting the CNS. Subsequently, caffeine also has potential side effects. For example, low doses cause anxiety gastrointestinal discomfort and inability to focus, while high doses can cause arrhythmias and mild hallucinations [22]. Cocaine Cocaine similar to the other stimulants mentioned stimulates the CNS and the sympathetic nervous system [5]. Hence, it was used by native South Americans to increase physical endurance, vigor, and efficiency [4]. As well, a review by Smith and Perry [23] concluded that there is a reason to suspect minor doses of cocaine yielding an effect on sports performance, as this drug has a very comparable catecholamine activity to that of amphetamines. Correspondingly, the enhancement seen in performance produced by cocaine can be attributed to it releasing noradrenaline from neurons and more importantly inhibiting the reuptake of noradrenaline and dopamine, in turn heightening the effect of these neurotransmitters [5].

In spite of cocaine being a conceivable ergogenic aid, this drug is more noticeable for distorting an athlete’s reality, for example, the sense of euphoria evoked by this drug may provide an illusion of better performance when in fact performance did not get any better [5]. Implying, cocaine has a detrimental effect on an individual’s performance. Not only is cocaine, not an ergogenic aid, the use of it can give rise to health complications. These include arrhythmias, hypertension, acute myocardial infarctions, myocardial ischemia, cardiomyopathy and endocarditis [24].

Overall, regardless of stimulants side effects, athletes still take legal or illegal stimulants to increase their performance levels during competition. Research has concluded this is because stimulants act on the CNS, induce the release of neurotransmitters such as noradrenaline and dopamine and acts as an adenosine receptor agonist. This, in turn, increases free fatty acid utilization, the force of skeletal muscle contraction, blood pressure, body temperature and heart rate. Hence, the enhancement of an individual’s alertness, anaerobic performance, endurance and reduction in fatigue. So, it can be claimed that stimulants are ergogenic in nature as it raises one’s performance level during the time of competition."