Robert Has Been Visiting His Physician for an Annual Physical

Robert has been visiting his physician for an annual physical every spring since he retired a decade ago. This year, Robert tells his doctor that he has taken up several new hobbies in an effort to ward off "old age." He then tells his doctor all about his winter schedule, which included curling, learning Spanish, knitting, and yoga. Upon hearing about these new activities, Robert's doctor tells him that his decreased systemic blood pressure and increased muscle mass, endurance, and strength make sense now. What is the most likely explanation for these changes in Robert's health?

A) Robert's doctor misinterpreted his chart.
B) Learning a language has an impact on physical health.
C) Robert is experiencing the benefits of increased social activities.
D) Robert is experiencing the benefits of regular physical activity.