The man who dared to boldly go where no one had gone before has revealed that he can't go as many places as he used to. 

"I'm doing OK," Leonard Nimoy tweeted Friday. "Just can't walk distances. Love my life, family, friends and followers." 

Nimoy announced last week that he has been diagnosed with chronic obstructive pulmonary disease -- 30 years after having given up cigarettes. 

"Not soon enough," tweeted the 82-year-old actor and director who played Spock, the half-human science officer aboard the Starship Enterprise from 1966 to 1969 on the TV series "Star Trek" and in movies during the decades since. "I have COPD. Grandpa says, quit now!!! LLAP." 

The last reference is to his signature phrase, "Live long and prosper." 

Nimoy, who told an interviewer last year that he flunked chemistry in high school, may not have grasped the long-term risks associated with smoking, but his announcement is not surprising, said Dr. Richard Casaburi, a pulmonologist at Los Angeles Biomedical Research Institute in Torrance, California. 

Smoking could very well be responsible for the appearance of symptoms of COPD decades after quitting, because it is a progressive disease and lung function declines with age, said Casaburi, who is not involved with Nimoy's treatment. 

COPD is the third-leading cause of death in the United States -- after heart disease and cancer -- and smoking is responsible for the vast majority of cases, he said. 

Some 12 million people in the United States have been diagnosed with the disease, and perhaps another 12 million have it, but don't know, he said, adding that about 30% of people who smoke will get clinically significant COPD. "The mystery really is why everybody doesn't get it." 
What sickness has he got?
Nimoy announced last week that he has been diagnosed with chronic obstructive pulmonary disease