Question

.The graph represents a person’s heart rate in beats per minute during 30 minutes of exercise.

A graph titled Cardiac Exercise. The horizontal axis shows time (minutes), numbered 3 to 30, and the vertical axis shows Heart Rate (b p m) numbered 15 to 150. The line starts at 75 b p m in 0 minutes, to 135 b p m from 6 to 25 minutes, and ends at 105 b p m at 30 minutes.

Which statement best describes the relationship between heart rate and time during exercise?

The heart rate increases for 6 minutes, remains constant for 19 minutes, and then gradually increases for 5 minutes.
The heart rate decreases for 6 minutes, remains constant for 19 minutes, and then gradually increases for 5 minutes.
The heart rate increases for 6 minutes, remains constant for 19 minutes, and then gradually decreases for 5 minutes.
The heart rate remains constant for 6 minutes, increases for 19 minutes, and then gradually decreases for 5 minutes.

Answer 1

The heart rate increases for 6 minutes, remains constant for 19 minutes, and then gradually decreases for 5 minutes.

Explanation:

Based on the description of the graph, the heart rate starts at 75 bpm and then increases for the first 6 minutes of exercise until it reaches a maximum of 135 bpm. The heart rate then remains constant (i.e. does not increase or decrease) for the next 19 minutes of exercise. Finally, during the last 5 minutes of exercise, the heart rate gradually decreases from 135 bpm to 105 bpm.

Therefore, the correct statement that describes the relationship between heart rate and time during exercise is "The heart rate increases for 6 minutes, remains constant for 19 minutes, and then gradually decreases for 5 minutes."