I studied physics before doing medicine, and id say medicine required about 10% the intellectual capacity. There's a lot of hard work to do studying medicine, but concerning the "smartness" it's not so challenging.B.
And as a doctor, I wouldn't speculate on the percentage of mental capacity it takes. Let's just say, when you are treating patients, you had better give it 100%.P.S. Everyone knows smart and not-so-smart people in all fields.