Question

the graph represents a persons heart rate in beats per minute during 30 minutes of exercise. 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. cardiac exercise

Explanation:

Step1: Analyze the graph

The graph shows that the heart rate increases for the first 6 minutes (from \(t = 0\) to \(t=6\)), then remains constant from \(t = 6\) to \(t = 19\) (a duration of \(19 - 6=13\) minutes, but let's check the options. The closest is 10 - minute constant in the options). After that, it gradually decreases for the last part.

Step2: Match with options

• Option 1: Incorrect as the constant - time is not 6 minutes.
• Option 2: Incorrect as the heart rate does not decrease first.
• Option 3: Correct. The heart rate increases for 6 minutes, remains constant (approx 10 - minute range in the graph's constant - part) and then decreases.
• Option 4: Incorrect as the heart rate does not start constant.

Answer:

The heart rate increases for 6 minutes, remains constant for 10 minutes, and then gradually decreases for 5 minutes.