The effects of oral smokeless tobacco administration on endurance performance

BACKGROUND

Smokeless tobacco is widely used by athletes to enhance performance. Nicotine is a central nervous system stimulant and acts on cardiocirculatory and metabolic systems, involving tissue blood flow and circulatory vasoreactivity. The aim of this study was to investigate the effects of the oral smokeless tobacco (Swedish snus (SS)) on the perception of fatigue and time to exhaustion (TTE) during moderate-intensity aerobic exercise.

METHODS

Fourteen healthy non-tobacco male users were recruited for a double-blind, controlled crossover design (SS vs. snus placebo (SP)). Subjects were tested for 3 sessions: experimental session 1 (Exp1) consisted of an incremental test to determine the maximal aerobic power output (W_max), whereas Exp2 and Exp3 consisted of exercising at 65%W_max until exhaustion in SS or SP conditions. During Exp2 and Exp3, muscle and cerebral oxygenation was assessed by means of near-infrared spectroscopy, and the rating of perceived exertion (RPE) was recorded.

RESULTS

Comparing SS with SP tests, significant differences (p < 0.05) were found in the values of cerebral (~3%) and muscular tissues oxygenation (~4%) in the first 30 min of exercise. The RPE values were not significantly different between the 2 conditions (SS vs. SP). No significant difference was found in TTE (SS: 54.25 ± 21.84 min; SP: 50.01 ± 17.03 min).

CONCLUSION

This study showed that muscular and cerebral oxygenation increased significantly with snus administration during an endurance exercise until exhaustion, but this did not affect fatigue perception and TTE. The results showed that snus could not be considered an ergogenic substance in non-tobacco users.

[Old and new tobacco products]

Tobacco use is not just about manufactured cigarettes. Rolling tobacco, highly prized in the wake of price increases, is estimated to carry more toxic agents than its counterpart. This study shows that the use of cigar, pipe, cigarillos and narghile also leads to a cohort of pathologies similar to or more than what is known for smoking single cigarettes. Exotic, liquid or heated forms do just as much. The non-smoked tobacco, often fallen into disuse in France is very used in the United States and especially in Scandinavia. Denuded of inhaled products, it is often pointed as a form of reduction of smoking risks. Its use by athletes in all countries as a doping attitude, especially in ski disciplines, required a campaign of prevention within the federations concerned.

Physical Activity and Snus: Is There a Link?

The study aimed at assessing the link between physical activity (PA), sports activity and snus use among young men in Switzerland. Data from the Cohort Study on Substance Use Risk Factors (C-SURF) were used to measure PA with the International Physical Activity Questionnaire and sports activity with a single item. Multivariate logistic regression analysis was conducted to measure the association between snus use, PA and sports activity. Similar models were run for smoking and snuff use. Snus use increased in a dose-response association with PA (high level: OR = 1.72; 95% CI 1.16-2.55) and with individuals exercising once a week or more often (OR = 1.65; 95% CI 1.26-2.16; p < 0.001) or almost every day (OR = 2.27; 95% CI 1.72-3.01; p < 0.001) in separate models. Entered simultaneously, only sports and exercise maintained a basically unchanged significant dose-response relationship, whereas PA became non-significant. A non-significant dose-response relation was found for cigarette smoking and snuff use, indicating that the association with sport is specific to snus and not to tobacco use in general or smokeless tobacco in particular. This study showed that the association between snus use and sports is not specific to Nordic countries.

Smokeless tobacco, sport and the heart

Smokeless tobacco (snuff) is a finely ground or shredded tobacco that is sniffed through the nose or placed between the cheek and gum. Chewing tobacco is used by putting a wad of tobacco inside the cheek. Smokeless tobacco is widely used by young athletes to enhance performance because nicotine improves some aspects of physiology. However, smokeless tobacco has harmful health effects, including cardiovascular disorders, linked to nicotine physiological effects, mainly through catecholamine release. Nicotine decreases heart rate variability and the ventricular fibrillation threshold, and promotes the occurrence of various arrhythmias; it also impairs endothelial-dependent vasodilation and could therefore promote premature atherogenesis. At rest, heart rate, blood pressure, inotropism, cardiac output and myocardial oxygen consumption are increased by nicotine, leading to an imbalance between myocardial oxygen demand and supply. The same occurs at submaximal levels of exercise. These increases are accompanied by a rise in systemic resistances. At maximal exercise, heart rate, cardiac output and maximal oxygen uptake (V˙O2max) are unaffected by nicotine. Because endothelial dysfunction is promoted by nicotine, paradoxical coronary vasoconstriction may occur during exercise and recovery. Nicotine induces a decrease in muscular strength and impairs anaerobic performance. However, nicotine is used in sports as it diminishes anxiety, enhances concentration and agility, improves aerobic performance and favours weight control. Importantly, smokeless tobacco, similar to cigarette smoking, leads to nicotine dependence through dopaminergic pathways. Smokeless tobacco has harmful cardiovascular effects and is addictive: it fulfils all the criteria for inclusion in the World Anti-Doping Agency prohibited list as a doping product. Smokeless tobacco use in sporting activities must be discouraged.