What are ergogenic aids?

Introduction

In the history of sport, athletes have attempted to find a competitive advantage through advanced techniques in training, nutrition, and even in ergogenic aids, such as nutritional supplements and pharmacological aids. The use of these substances—such as anabolic-androgenic steroids (AAS), testosterone precursors (such as androstenedione), and nonsteroidal aids such as human growth hormone (GH) and creatine—have become increasingly popular in recent years, even without thorough scientific data supporting their efficacy and safety.

The population using such performance-enhancing drugs ranges from collegiate to professional athletes to adolescents and high school students. Recent meta-analyses estimate that 3 to 12 percent of adolescent boys have used an anabolic steroid
at least once, and 28 percent of collegiate athletes admit to taking creatine. Other studies have suggested that the number may be closer to 41 percent.

Though such ergogenic aids are thought to improve strength, endurance, agility, and overall performance, most athletic improvement is anecdotal at best. Scientific evidence supporting these ideas is scarce and incomplete. Even with aids that may improve strength and/or performance, the safety of these substances has been seriously questioned, such as with the use of AAS, GH, and ephedra.

Types of Ergogenic Aids

Anabolic-androgenic steroids (AAS) as ergogenic aids in sports are chemical compounds that resemble the structure of testosterone, the naturally occurring male sex hormone that affects muscle growth and strength. “Anabolic” refers to the growth of cells, and “androgenic” refers to the stimulation of the growth of male sex organs and masculine sex characteristics. AAS bind to cells that are used for muscle repair and that can transform into muscle fibers.

AAS has been one of the most studied ergogenic aids, yet many of its mechanisms and adverse effects are still not well understood. Studies have shown that increased doses of testosterone can decrease total body adipose tissue in the body and can increase strength and fat-free mass. Adverse effects of AAS use include hypothalamic-pituitary dysfunction, gynecomastia, severe acne, infection as a result of sharing needles, aggressive and depressive behavior, and a possible association with premature death.

Androstenedione (andro) is a testosterone precursor produced by the adrenal glands and gonads. Its ergogenic effect occurs after it is converted to testosterone in the testes as well as in other tissues. It can also be converted to estrone and estradiol, which are steroid compounds that are primary female sex hormones (found in both men and women). The creation of testosterone is regulated by the amount of testosterone precursors in the body. Theoretically, an increase in androstenedione would increase the production of testosterone and thus can increase protein synthesis, lean body mass, and strength.

Older studies showed that andro supplementation results in increased serum testosterone levels. However, more recent studies have shown that andro supplementation fails to directly improve lean body mass, muscular strength, or serum testosterone levels. Possible side effects to andro use are suppressed testosterone production, liver dysfunction, cardiovascular disease, testicular atrophy, baldness, acne, and aggressive behavior.

Similar to androstenedione, dihydroepiandrosterone (DHEA) is a precursor of testosterone and is also formed in the adrenal glands and gonads. DHEA is the most abundant steroid hormone in circulation and is a precursor to androstenedione and other testosterone precursors (such as androstenediol). Studies of DHEA supplementation have not been shown to increase lean body mass, strength, or testosterone levels. Possible side effects are similar to andro and AAS use.

Human growth hormone (GH) is a metabolic hormone that is secreted into the blood by cells found in the anterior pituitary gland. After its secretion, GH stimulates the production of insulin-like growth factor (IGF)-1 in the liver. These hormones stimulate bone growth, protein synthesis, and the conversion of fat to energy. Athletes have been attracted to GH not only because of such theoretical benefits but also because of the limited techniques in detecting GH in the urine. GH levels vary in individuals of different, ages, sex, and activity and can vary throughout the day, so no reliable benchmark can be made to determine if illicit use has taken place.

Scientific studies have been unable to show that GH leads to increased muscle strength and exercise performance or changes in protein synthesis. Because of ethical limitations, it is difficult to study the effect of larger doses of GH on healthy individuals. Adverse effects of GH use include cosmetic damage, joint pain, muscle weakness, fluid retention, impaired glucose regulation (which may lead to diabetes mellitus), cardiomyopathy, hyperlipidemia, and possibly death.

Erythropoieten (EPO) is a hormone secreted by the kidneys that is a precursor to bone marrow. EPO increases the oxygen-carrying capacity of blood and, as a result, aids in endurance and aerobic respiration. The appeal of EPO among athletes is this endurance-enhancing effect. As a result, many users have been found to be skiers, cyclists, and other athletes who require high levels of endurance. Early use of EPO as an ergogenic aid, termed “blood doping,” came in the form of autologous blood transfusions, in which athletes would harvest their own red blood cells and reintroduce them into their systems before events. A synthetic form of EPO, recombinant human erythropoietin (r-HuEPO) became available in 1988.

Scientific studies have shown that EPO and r-HuEPO treatments do increase certain blood concentrations and can aid in endurance. EPO may also have serious and dangerous side effects, however, such as hypertension, seizures, thromboembolic events, and possibly death.

Creatine monohydrate is an amine synthesized in the kidneys, pancreas, and liver, and it can also be obtained through the diet from meat and fish. Approximately 90 to 95 percent of creatine in the body is found in skeletal muscle. Creatine, which is converted to creatine phosphate (PCr), is an important limiting factor in the resynthesis of adenosine triphosphate (ATP), which plays a significant role in energy reserves within the body. Theoretically, an increase of PCr in the body would increase the regeneration of ATP, resulting in an increase in sustained maximal energy production for short-term exercise. This could lead to increased intensity and repetition frequency, and thus possible increases in skeletal muscle mass.

In 2002, A. M. Bohn and colleagues argued in an article in Current Sports Medicine Reports that there are “no studies demonstrating benefit with the relatively indiscriminant use of variable amounts of creatine by large numbers of athletes on a specific team.” Nevertheless, creatine has been shown to enhance performance in small populations of athletes of various sports. Possible adverse effects of creatine include muscle cramping, dehydration, gastrointestinal distress, weight gain, increased risk of muscle tears, inhibited insulin and creatine production, renal damage, and possibly nephropathy.

Stimulants are drugs that increase nervous system activity. Examples of stimulants commonly used as ergogenic aids include the class of drugs called amphetamines, as well as specific chemical compounds such as caffeine and ephedrine. The use of caffeine has been shown to improve exercise time to exhaustion and may even significantly increase intestinal glucose absorption. It has been suggested that caffeine increases fat utilization for energy and delays the depletion of glycogen (the stored form of glucose). As a result, caffeine and other stimulants are popular ergogenic aids for extended aerobic activity.

Caffeine in small doses has been shown to increase performance. Possible adverse effects of caffeine may include anxiety, dependency, withdrawal, and possibly a diuretic effect (dehydration). Ephedrine may have similar adverse affects. Other stimulants, such as amphetamines or cocaine, have more serious and detrimental effects.

Perspective and Prospects

The use of ergogenic aids in the history of sport has progressively moved from primitive aids to more sophisticated performance enhancers. Crude natural concoctions and stimulants have paved the way for complex pharmacological agents (such as erythropoietin) and designer
anabolic steroids (such as tetrahydrogestrinone). Athletes and trainers have utilized any and all means to gain a competitive edge, even if that results in damage to health and even a risk of death.

The biggest problem stemming from the use of such aids is the difficulty in detecting them. This is evident in recent media attention given to ergogenic aids and their popularity, as seen through the 2007 Mitchell Report, an independent congressional investigation of the use of performance-enhancing drugs in Major League Baseball, as well as the 2012 discoveries of abuse by high-profile cyclists and athletes at the Summer Olympics held in London. This media attention has also shown the difficulties among investigators, such as the International Olympic Committee, the World Anti-Doping Agency, and the United States Anti-Doping Agency, in detecting the use of new designer steroids and new ergogenic aids among elite athletes.

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