Which of the following conditions does NOT represent a risk factor for infection following cardiac surgery?

Regular exercise is associated with numerous health benefits, including improved cardiovascular fitness, enhanced immune function, and better overall recovery from surgical procedures. Engaging in regular physical activity can help strengthen the immune system, decrease the risk of postoperative complications, and promote better wound healing. Because of these positive effects, regular exercise does not constitute a risk factor for infection following cardiac surgery.

In contrast, diabetes, obesity, and prolonged intubation are all recognized risk factors that can contribute to increased susceptibility to infections. Diabetes can impair immune function and wound healing, which can lead to a higher risk of surgical site infections. Obesity is often linked to a variety of complications, including poor wound healing and greater strain on the respiratory system, further increasing risks. Prolonged intubation may lead to ventilator-associated pneumonia and other respiratory infections. Thus, while regular exercise supports recovery and reduces risks, the other conditions can compromise the body's ability to fight infections post-surgery.