The average person takes more than 20,000 breaths on any given day. Imagine fighting for every one of them.
That's the reality for millions of Americans with emphysema, bronchitis, asthma and other lung diseases.
Though better treatments have improved many patients' lives, some of the conditions still defy modern medicine. Overall, chronic lung disease is the fourth-leading cause of death in Florida and across the nation.
Symptoms usually start with a nagging cough, then grow into shortness of breath during exertion. It only gets worse with time.
"Eventually, you get shortness of breath even when you're doing nothing at all," said Dr. Fortune Alabi, a Florida Hospital pulmonologist at Celebration Health in Osceola County. "By the time I see many patients they are so far along, there is very little I can do for them."
The state estimates nearly 9,000 Florida residents die from chronic lung disease each year. The best way to protect yourself is also the most obvious: Don't smoke. Other tips include staying indoors when pollution levels are high and avoiding triggers for breathing attacks if you have asthma.
The lungs are large, elastic organs that supply the body with fresh oxygen and rid it of carbon dioxide gas. Each lung holds a dense network of airways that culminate in tiny, sac-like clusters called alveoli.
Problems with the tubes and these little sacs make it harder to breathe.
One of the most deadly lung conditions is called COPD, a catchall term that stands for chronic obstructive pulmonary disease. The airways are inflamed, narrowed and often filled with secretions in COPD patients, who are diagnosed by their symptoms, personal risk factors (smoking history), lung function tests and chest X-rays.
Two conditions fall under the broader category of COPD: emphysema and chronic bronchitis. But doctors often don't distinguish between them because they are treated in the same way. Patients rely on multiple medications and breathing treatments with a nebulizer, which creates a medicated mist to open the airways.
Many have oxygen machines in their homes and use them frequently to get the fresh air that their lungs can no longer provide. They take small, portable oxygen tanks with them everywhere just in case. The loss of lung function is progressive -- though it's slow in some and faster in others.
Alabi said there is no cure for COPD and often, existing treatments are not very effective.
"There are medicines that can reduce the symptoms to have a better quality of life," he said. "But most of the medicines just make you feel a little bit better. Once the damage starts, it's irreversible; the disease is not going to go away."
About 12 million Americans have been diagnosed with the condition, and experts suspect that an equal number are developing the disease.
Dr. Adam Wanner is a pulmonologist and professor at the University of Miami's school of medicine. He said smoking is the major cause of COPD in western countries such as the United States, where about 80 percent of cases are linked to cigarettes. But that doesn't mean most smokers get COPD. Overall, about 20 percent develop the condition.
For the unlucky ones, it is a devastating diagnosis.
"It is a frustrating disease in terms of treatment, but if you can give the patient just a 10- to 15-percent improvement in lung function, that's a lot when every breath is an effort," said Wanner, who also works with the COPD Foundation based in Miami.
Cecilia Adams of Kissimmee has been living with lung disease for more than a decade. On a recent day, she managed to unfurl her garden hose and water the flowers beside her front porch. That's an accomplishment.
"Every year I can tell it gets a little bit worse," said Adams, 66, who has emphysema. "I'm just very careful. I know how far I can push myself, then I stop."
Asthma is another major form of chronic lung disease. It differs from COPD in that asthma doesn't cause permanent damage to the lung tissue.
Instead, patients suffer from chronic inflammation and tightening of the airways. The condition can be controlled with medications and a solid treatment plan, said Dr. Jose R. Arias Jr., an Orlando doctor who specializes in allergies and asthma.
Even so, the disease is demanding. It affects an estimated 22 million Americans, often starting in childhood and requiring a complex daily regimen of medications that includes inhalers, pills and nebulizers.
Asthma can be connected to allergies that spark the sudden and life-threatening breathing attacks. Other triggers are exercise and cold weather.
Being overweight also makes asthma worse. Arias tells his patients that every 10 pounds of excess fat is like stacking a brick on the chest and trying to breathe.
He said asthma kills an estimated 4,000 Americans every year. It is a major cause of emergency-room visits and absenteeism at work and school.
"If your asthma is controlled, you have a normal life; if it's not controlled, you're going to be very limited," Arias said. "You're going to feel tired and irritable, and you're going to have a hard time doing anything. It can have a major, major impact" on a person's life.
More lung conditions
Here are other chronic lung diseases, as described by the American Lung Association:
*Pulmonary fibrosis occurs when tissue between the air sacs in the lungs becomes scarred, making the lungs thick and breathing difficult. The cause is often unknown, though some people develop pulmonary fibrosis after exposure to asbestos and other contaminants.
*Alpha-1 related emphysema is an inherited form of the disease in which people fail to make a protein that normally protects the lungs. Damage results and patients progressively lose lung function.
*Cystic fibrosis is a hereditary disease that causes a thick mucus to form in the lungs, blocking the airways. On average, CF patients live about 37 years, according to the Cystic Fibrosis Foundation.
Robyn Shelton can be reached at firstname.lastname@example.org or 407-420-5487.