I just saw my internist and he adamantly said I need to go for a colonoscopy even though my exam and blood work were normal . I am 55 years old and have run 30 or miles a week for the past 35 years . I am as healthy as anyone and there is no history of colon cancer in my family . Do I really need this test ?

Question: Why might I feel this way about the test ?
Answer: I am scared about the test since the doctor adamantly said I need to go for a colonoscopy .I exercise regularly and have no family history of the condition so I am annoyed that I need the test .I am worried about the colonoscopy   since my exam and blood work were normal .I exercise regularly and have no family history of the condition so I am confused why I need the test .