The effects of caffeine, nicotine, ethanol, and tetrahydrocannabinol on exercise perf

Stannis

[size=large]The effects of caffeine, nicotine, ethanol, and tetrahydrocannabinol on exercise performance[/size]


http://www.nutritionandmetabolism.com/content/10/1/71

Caffeine

Summary
In summary, caffeine, even at physiological doses (3–6 mg/kg), as well as coffee are proven ergogenic aids and as such – in most exercise situations, especially in endurance-type events – clearly work-enhancing [26]. It most likely has a peripheral effect targeting skeletal muscle metabolism as well as a central effect targeting the brain to enhance performance, especially during endurance events (see Table 1). Also for anaerobic tasks, the effect of caffeine on the CNS might be most relevant. Further, post-exercise caffeine intake seems to benefit recovery be increasing rates of glycogen resynthesis.

Nicotine

Summary
In summary, nicotine seems to have ergogenic potential. Athletes appear to benefit from activation of the sympathoadrenal system with increased catecholamine release and subsequent increases in muscle blood flow and lipolysis. One component of nicotine action seems to act via a central mechanism (by nicotine receptor activation and/or dopaminergic pathways; see Table 2). There is evidence for the abuse of nicotine by athletes. Although the sale of snus is illegal within the European Union [107], anecdotal observations by coaches and research from Scandinavia shows a high prevalence of snus use among athletes [83,108]. It might therefore be reasonable to assume that smoking cigarettes will not be an issue for athletes. Instead, as there are several nicotine alternatives many of the negative effects of cigarettes can be circumvented.

Ethanol (alcohol)

Summary
Alcohol is the most commonly consumed drug in athletic communities. The American College of Sports Medicine (ACSM) concludes in its position stand that alcohol consumption adversely affects psychomotor skills and exercise performance while resulting in minimal reductions in maximal oxygen consumption (see also Table 3). The ACSM also recommends that if an athlete must consume alcohol, that they should refrain from alcohol consumption for at least 48 hours prior to competition. Chronic alcohol abuse is associated with significant impairments in cardiac and skeletal muscle. It also slows post-exercise recovery by inhibiting protein synthesis. Thus, alcohol is a uniformly ergolytic agent that has significant detrimental effects on exercise performance and that use of the same during competitive activity should be minimized for athlete safety and so as to maximize athletic performance.

Tetrahydrocannabinol - Cannabis (Cannabis sativa)

Summary
Overall, it appears that cannabis does not have ergogenic potential in sports activities and thus, its inclusion on the banned list is likely a function of its illicitness. As cannabis smoking impairs exercise and psychomotor performance (such as sedative effect, slower reaction times and other psychomotor effects), its ability to serve as an ergogenic aid has been questioned, and is generally considered to be an ergolytic drug (see also Table 4). This is likely due to increase in heart rate and blood pressure, decline of cardiac output and reduced psychomotor activity that have been demonstrated in prior studies.