Thursday, March 21, 2013

Nicotine Increases Exercise Endurance

In my lectures on tobacco harm reduction I compare the properties of nicotine with those of caffeine (see slides at left).  Despite some obvious differences, the drugs have remarkably similar effects.  I have just found a study from 2006 showing that “…nicotine administration during moderate-intensity exercise delays fatigue, with a significant improvement of 17% [±7%] in time to exhaustion. This observation is similar to observations of the effects of caffeine supplementation.” (Available at the journal Experimental Physiology here).

Authors Toby Műndel and David A. Jones of the Human Performance Laboratory, School of Sport and Exercise Sciences, The University of Birmingham (United Kingdom), recruited 12 healthy non-smoking men and asked them to cycle in a laboratory setting at a moderate pace until exhausted on two occasions.  Subjects randomly applied either a 7 milligram nicotine patch or a placebo patch the evening before.  

Ten subjects who wore the nicotine patch cycled for 70 minutes – about 17% longer than the 62 minutes cycled by those with the placebo patch.  Nicotine had no effect on heart rate or respiratory parameters, and it “…did not alter the perception of effort… associated with progressive fatigue.”  The researchers noted that “…activity of dopamine pathways has
been suggested to be associated with improved endurance exercise performance.”  In other words, nicotine’s endurance boost stemmed from its effect on the brain. 

As I mentioned in 2011 (here), the World Anti-Doping Agency (WADA) is considering labeling nicotine a performance-enhancing drug.  However, WADA could treat nicotine as it has caffeine, summarized this way by the agency in 2012 (here):

“Caffeine was removed from the Prohibited List in 2004. Its use in sport is not prohibited.  Many experts believe that caffeine is ubiquitous in beverages and food and that reducing the threshold might therefore create the risk of sanctioning athletes for social or diet consumption of caffeine.  In addition, caffeine is metabolized at very different rates in individuals.”

Since using nicotine is a “social” choice and the substance is metabolized at very different rates, one can only hope that WADA applies such a reasoned, practical analysis to it as well.

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