Cardiorespiratory exercise is defined as?

• A. Continuous, rhythmic exercise lasting ≥10 minutes
• B. Short, explosive efforts
• C. Exercises using only upper body
• D. Never changes heart rate

Answer: (A)

Cardiorespiratory exercise is about using the heart and lungs to supply oxygen during sustained, rhythmic movement of large muscle groups. The best choice describes continuous, rhythmic activity that lasts long enough—at least about 10 minutes—to keep the body in an aerobic, oxygen-using state and to raise and maintain heart rate and breathing.

This fits because aerobic work relies on a steady pace that the body can sustain, engaging the circulatory and respiratory systems over a period of time. Examples include brisk walking, cycling, swimming, or dancing at a comfortable, continuous pace.

The other ideas don’t fit as well: very short, explosive efforts rely mainly on anaerobic energy systems; exercising with only the upper body can be less effective for elevating overall heart rate and may not meet the standard definition that emphasizes continuous, rhythmic activity involving larger muscle groups; and an exercise that never changes heart rate isn’t characteristic of cardiorespiratory training, which aims to elevate and sustain heart rate to improve endurance.