TAKE-HOME POINTS
■ Performance-enhancing practices aid competitive skill or endurance, facilitate training and recovery, or help elude fair testing standards; they are generally task- or sport-specific.
■ The list of performance-enhancing substances is extensive and includes prescription drugs, OTC medications and supplements, and some prepared “foods.”
■ Awareness of a patient's avocational interests can be helpful in anticipating the nature of performanceenhancing practices.
■ Be alert for performance-enhancing practices in any patients who are engaged in competition or sports, or
who have recent significant changes in physique or health status; and ask specific questions about such practices.
WHO SHOULD READ THIS?
Any physician assistant who cares for patients who participate in recreational or competitive activities may encounter a person who is using a performance-enhancing substance or technique (such as blood doping).
WHAT ARE PERFORMANCE-ENHANCING SUBSTANCES?
In a 2005 policy statement, the American Academy of Pediatrics defined performance-enhancing substances as follows:
A substance should be considered performance enhancing if it benefits sports performance by increasing strength, power, speed, or endurance (ergogenic) or by altering body weight or body composition. Furthermore, substances that improve performance by causing changes in behavior, arousal level, and/or perception of pain should be considered performance enhancing.1
Many OTC products are marketed for their performance-enhancing properties. Furthermore, additional products are available through special providers. These range from so-called power foods to neutraceuticals and are often consumed in higher-than-recommended amounts when used as performance enhancers.2,3
Caffeine is the most commonly used performance enhancer. Eight ounces of brewed coffee contains 60 to 120 mg of caffeine. The caffeine concentration in caffeinated beverages ranges from 0 to 141 mg/serving. Both habitual and acute caffeine consumption increase BP.4,5 The effects of caffeine on cardiovascular and endothelial function are still under investigation.4-9 Because caffeine is ubiquitous in Western diets and in many dietary supplements, evaluation of persons with cardiovascular symptoms should include asking about caffeine consumption and use
of supplements. Some serious indicators of possible supplement abuse include syncope, arrhythmias, hypertension, antisocial aggressive behavior, and impaired renal function. Tendon injuries may occur with anabolic steroid abuse, and impaired hematologic parameters may suggest erythropoietin or diuretic abuse.
Human growth hormone (HGH) has the potential for abuse because of the high cost of effective detection tests and its relatively short half-life.10-12Erythropoietin injections have been used illicitly to increase RBC production and thus improve oxygen-carrying capacity and endurance.10-12
The World Anti-Doping Agency (WADA) is an independent agency funded by international governments and sports federations to coordinate and monitor the fight against doping in sports. Hundreds of prescription drugs, as well as creatine and many OTC products, are banned by WADA. The list includes diuretics, which are used for weight loss and to mask illicit drug use; beta-blockers, which aid performance in target sports such as archery and curling;10 anabolic steroids; amphetamines; erythropoietin; and HGH11 (Table: Selected products prohibited by WADA in the online version of this article).
The evolution of DNA technology for medical therapy is paralleled by gene-doping strategies developed throughout the world. Targets already identified for gene-doping include peroxisome proliferator-activated receptor-delta, which can modulate energy utilization, and myostatin-inhibitor genes, which can increase muscle bulk.13