Which of the following is a significant side effect of long-term exposure to high concentrations of oxygen?

Long-term exposure to high concentrations of oxygen can lead to oxygen toxicity, which significantly affects the lungs and the nervous system. This condition arises from the toxic effects of reactive oxygen species produced when oxygen is present in excessively high amounts. In the lungs, oxygen toxicity can result in symptoms such as inflammation, pulmonary edema, and damage to the alveoli, which can impair gas exchange.

In the nervous system, oxygen toxicity can cause neurological symptoms due to oxidative stress, potentially leading to seizures or other complications. Recognizing this side effect is crucial in medical gas therapy, as managing and monitoring oxygen levels appropriately can prevent adverse outcomes associated with prolonged exposure to high concentrations of oxygen.

The other options provided do not accurately describe the significant side effects associated with long-term high-concentration oxygen exposure. For example, while increased heart rate can occur in various medical scenarios, it is not a direct consequence of oxygen toxicity. Similarly, improved lung capacity does not result from exposure to high oxygen levels, and while short-term memory loss could be influenced by many factors, it is not a recognized direct effect of oxygen toxicity.