HEALTH TOPICS 
Asthma
Some men think of asthma as "kid stuff," a childhood illness. But they're wrong: the disease strikes people of all ages. Fortunately, lifestyle adjustments and proper medication will allow most asthmatics to lead full, active lives.
Your lungs, in health and in asthma
The average man takes more than 20,000 breaths a day. With each, air travels down the windpipe, then through smaller tubes called bronchi. Finally, the air arrives at the lungs' 300 million tiny air sacs, where oxygen crosses into the blood and carbon dioxide is removed (see figure).
To continue reading this article, you must login.
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.
- Research health conditions
- Check your symptoms
- Prepare for a doctor's visit or test
- Find the best treatments and procedures for you
- Explore options for better nutrition and exercise