An elderly man visited his doctor and began to describe his ailments. As the doctor inquired further, the man explained, "Well, Doc, after climbing to the first floor, I'm extremely tired. After the second, I feel completely worn out. After the third, my heart starts pounding. After the fourth, I break out in a cold sweat. And after the fifth, I'm so exhausted, I feel like I'm going to die right then and there!"
"That's incredible," said the doctor. "But how old are you?"
"Eighty-five," replied the patient.
The doctor said, "Well, at 85, why don't you just stop after the first floor?"
The man answered, "I can't stop. I live on the fifth floor!"