The influence of anabolic steroids on physiologic processes and exercise

Introduction  

Anabolic-androgenic steroids (AAS) are a group of synthetic compounds that mimic the effects of testosterone in the body. AAS are often abused by individuals to utilize their anabolic effect with the intended purpose of increasing lean muscle mass. AAS can have profound effects on the cardiovascular system with extended abuse.

Cardiovascular Effects

Long-term use of supraphysiological doses of AAS use has been attributed to an increase risk of pathological changes in the cardiovascular system that can result in: myocardial infarction, cardiomyopathy, sudden death, cardiovascular morbidity, and mortality when compared to non-users . AAS users have been shown to have a lower amount of heart rate variability (HRV) than non-users, putting them at an increased risk of autonomic cardiovascular dysfunction and ventricular arrhythmia . Some evidence suggests a causal link between power athletes, body builders, and supraphysiological AAS use with atrial fibrillation (AF) . This may be due to inter- and intra-atrial electromechanical delay. AAS users have been found to have a lower measurement of high frequency power, which is indicative of decresed vagal and parasympathetic activity in the heart. Reduced parasympathetic activity in the heart slows the recovery of heart rate post-exercise. However, the exact mechanism of how AAS abuse contributes to atrial electromechanical delay is poorly understood .

Muscular System Effects

Steroids have not been shown to increase creatine concentrations in the muscle, red blood cell concentration, or serum liver enzyme concentrations as previously postulated. One study found that injection of 600 mg of testoterone in adult males who did not exercise resulted in more fat free mass and a greater increase in strength than in individuals who incorporated resistance training but only took a placebo. Some commonly reported side effects of steroid use, such as acne and breast tenderness, resulted in some of the subjects as well but most did not. This would seem to indicate that individual physiological differences have a profound impact on how a person reacts to steroids.

Research indicates a significant correlation between prolonged AAS usage and upper extremity tendon rupture. Out of 88 AAS users, 17% had confirmed triceps or biceps tendon ruptures, whereas none of the non AAS users had upper extremity tendon ruptures   . No significant difference was found between the two groups concerning lower extremity tendon ruptures  . The mechanism of AAS-associated tendon rupture is not well understood. One hypothesis is that high doses of AAS use combined with intense muscular exercise may cause structural damage to the tendon themselves. All the evidence to date supporting this hypothesis comes from animal studies . One study found ultrastructural changes in tendons of mice treated with AAS . Wood, Cooke, and Goodshipsaw documented changes in collagen fibril crimp angle and fibril length of rat tendons exposed to AAS . Marqueti et al. noticed inhibition of matrix tendon remodeling in rats  and Tsitsilonis et al. documented reduced maximal stress values in rodents treated with AAS . Others have found biomechanical changes in rat tendons causing tendon stiffness . However, direct evidence of structural changes in human tendons has not been demonstrated . A case-control study compared collagen ultrastructure, metabolism, and mechanical properties of patella tendons in 24 individuals assigned to three groups: resistance-trained AAS users (RTS), resistance-trained non-AAS users (RT), and a control group that was neither AAS user nor resistance-trained (CTRL). Higher patellar stiffness and tensile modulus was found in the RTS group; this finding could support changes in tendon remodeling, however, there was no significant difference in mechanical and material properties of the tendons between the RTS and RT group respectively . A competing hypothesis suggests that AAS use causes hypertrophy in the muscle without causing corresponding changes in the tendon tissue. In times of sudden or maximal stress the muscle becomes too strong for its tendon causing injury . Lastly, a study on retired National Football League (NFL) players found an association between AAS users and an increased likelihood of musculoskeletal injury, specifically ligamentous injuries .

Most people relate anabolic steroids to high intensity training done by elite athletes. However, the idea has also come about to combine this drug with therapy to help the older population rehabilitate following hip replacement surgery. Anabolic Steroids can boost muscle development and increase other factors that relate to range of motion and strength in athletes. Experts agree with the perception that this will correspond with the older population when it comes to recovering from hip surgery . Anabolic steroids may also improve frailty. A randomized controlled study of 274 elderly men with frailty concluded that administering testosterone may improve quality of life by improving strength, physical function, and body composition. Researchers are interested in this concept and will continue to look into how anabolic steroids can be used to help the older population recover from hip surgery and improve overall quality of life.

Neurological Effects

AAS use is associated with positive and negative psychological effects. AAS abuse and dependence is a potential problem among AAS users, especially those using it for performance or aesthetic purposes. AAS may increase beta-endorphin levels, decrease cortisol levels, and increase ACTH levels, which may lead to an increase in positive associations with exercise.  The increase in endorphin levels and exercise reinforcement may contribute to AAS dependence and abuse. AAS dependence is characterized by increases in AAS cycles, higher doses, and increases in psychological disorders, such as increased aggression. Depression and suicide can be caused by off-cycles of AAS or withdrawal from AAS use.  The risk for depression and suicide may be caused by the decrease in endorphin levels and changes in the reward systems of the brain. AAS can cause or exaccerbate anxiety disorders, schizophrenia, and eating disorders.  The psychopathology of AAS is theorized to be caused by direct or indirect changes in the central nervous system, including changes to intracellular receptors and neruotransmitter receptors. These changes may influence hormone and neurotransmitter levels, such as serotonin or GABA, and lead to changes in depression, anger, or stress. AAS use may contribute to motivation and positive experiences with exercise, but it can lead to negative effects that are long-lasting and decreases in motivation to exercise.

Psychological Effects

Anabolic steroids are drugs that have many neuropsychiatric effects in addition to the more commonly known effects they have on skeletal muscles. Anabolic steroids cause not only negative feelings like intense anger but also some positive moods. Some of the negative feelings people have resulting from the use of anabolic steroids include irritability, mood swings, violent feelings, anger, and hostility. Positive feelings related to steroid use include euphoria, increased energy, and sexual arousal. Steroids are also linked to other cognitive symptoms like distractibility, forgetfulness, and confusion. These effects of steroid use occur independently of other factors. These impacts on mood could have either positive or negative effects on exercise, depending on the feelings of the person exercising.

References

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