For a dozen years, she had worsening shortness of breath symptoms.
"Like most people I tried to Ignore them, saying that I'm getting older and I just can't do the things I used to do," Horowitz said.
A new report says denying symptoms is common, even in people at risk for the Illness -- those over forty and those who smoke.
The study found that although 75 percent of people at risk had COPD symptoms, cough or shortness of breath, two-thirds of them did not know they had this very serious lung disease.
"there's been an historic under appreciation of COPD even though It Is the 4th leading cause of death and will soon overtake stroke as the third leading cause of death," Dr. Graham Barr of Columbia Medical Center said.
Underappreciated because patients don't report symptoms and doctors sometimes look for heart disease first rather than lung disease.
The advantage of patients telling their doctors and of doctors testing for COPD is that medications are available to improve someone's quality of life.
Ms. Horowitz uses inhaled medications, which open the airways and make breathing easier. She advises people not to follow her behavior.
"Don't swim in denial," she said. "The sooner the diagnosis is made, the sooner that it can be treated."