Final answer:
Steroids are known to have several negative side effects but they do not cause decreased exercise capacity; in fact, they are often misused for their performance-enhancing effects that can increase exercise capacity.
Step-by-step explanation:
Steroids have varied effects on the human body, but an effect they do not generally cause is a decreased exercise capacity. On the contrary, one of the reasons athletes use anabolic steroids is to increase muscle mass and performance, which can lead to an increase in exercise capacity. Steroid use is associated with numerous negative side effects, including severe acne, prostate disease, psychological aggression (often referred to as 'roid rage'), and a range of cardiovascular issues. Additionally, steroids can lead to hormonal imbalances causing physical changes such as testicular shrinkage in men and facial hair growth in women. However, they do not typically impede an athlete's ability to exercise but rather are misused for their performance-enhancing effects.