An eighty year old man was having an annual  physical. As

An eighty year old man was having an annual 
physical. As the doctor was listening to his heart 
with the stethoscope, he began muttering, "Uh oh!" 

The man asked the doctor what the problem was. 

"Well," said the doc, "you have a serious heart 
murmur. Do you smoke " 

"No," replied the man. 

"Do you drink in excess?" 

"No," replied the man. 

"Do you have a sex life?" 

"As a matter of fact, I do!" 

"Well," said the doc, "I'm afraid with this heart 
murmur, you'll have to give up half your sex life." 

Looking perplexed, the old man asked, "Which 
half...the LOOKING or the THINKING???"