What is a reason why anaerobic exercise may be dangerous?

• A. It uses oxygen efficiently
• B. It improves flexibility
• C. It reduces muscle mass
• D. Intensity making it difficult to sustain for a long period of time

Answer: (D)

The main factor being tested is that anaerobic exercise relies on very high intensity for short bursts, which can be dangerous because the body is pushed to near-maximum effort and cannot be sustained for long periods. When effort is so intense, heart rate and blood pressure rise quickly, fatigue sets in fast, and form can break down, increasing the risk of acute injuries, dizziness, dehydration, or overheating if proper precautions aren’t taken. Pushing beyond safe limits or skipping warm-ups amplifies these risks, making the sustained, intense effort the key danger.

The other ideas don’t explain the danger as clearly. Using oxygen efficiently is more aligned with aerobic activity, and while improving flexibility or muscle mass are useful effects of training, they aren’t the reason anaerobic bursts are risky.