Performances in endurance sports have been shrouded in controversy for the past 30 years because many athletes, intent on winning races and achieving faster times, have turned to banned performance-enhancing drugs. The World Anti-Doping Agency’s 2009 list of prohibited substances and methods includes erythropoietin, other erythropoiesis-stimulating agents and various methods designed to enhance oxygen transfer.1 The effects of these agents and methods are thought to be primarily beneficial in endurance sports such as distance running and cycling. Despite the prohibition, the use of these drugs and techniques persists, as evidenced by continued positive results of drug tests in and out of competition.
Altitude training has also become common among endurance athletes, because it has been associated with an increase in performance and in serum hemoglobin and hematocrit levels. However, this response is transient — the physiologic variables return to their baseline soon after the athlete returns to sea level.2 This moderate performance benefit is outweighed by several severe and life-threatening risks, including pulmonary edema,3 cerebral edema4 and severe flatulence.5
While athletes endanger their careers and well-being in attempts to gain small benefits with illicit or inconvenient practices, a legal, nonprescription alternative has been largely ignored by athletes, coaches and exercise physiologists alike. Cigarette smoking has been shown to increase serum hemoglobin and hematocrit levels, increase lung volume and stimulate weight loss — characteristics all known to enhance performance in endurance sports. This paper will discuss the potential benefits of cigarette smoking to endurance performance and make recommendations as to how individuals and national bodies could effectively integrate this practice into high-performance training programs.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001541/
Marginal gains?