According to the 2018 Physical Activity Guidelines for Americans, adults should aim for at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity aerobic activity each week, plus muscle-strengthening activities on two or more days a week.
Let's evaluate Arnold’s weekly workout plans based on this:
A. He golfs for 2 hours every Sunday.
- 2 hours = 120 minutes. This does not meet the minimum recommendation.
B. He bikes for 45 minutes a day, 3 days a week.
- 3 days x 45 minutes = 135 minutes. This does not meet the minimum recommendation.
C. He runs for 15 minutes a day, 6 days a week.
- 6 days x 15 minutes = 90 minutes. This does not meet the minimum recommendation.
D. He walks for 30 minutes a day, 5 days a week.
- 5 days x 30 minutes = 150 minutes. This meets the minimum recommendation.
Therefore, the only weekly workout plan that meets the minimum exercise recommendations is D. He walks for 30 minutes a day, 5 days a week.