For the proposed randomized controlled treatment study, the investigators plan to compare the effects of this hypoventilation-based breathing training with a control intervention that will focus on breathing regularity and awareness. The two therapeutic procedures are closely matched on important variables such as duration and the nature of patient-therapist interaction, monitoring asthma related status and the medication intake, use of scientific equipment and monitoring devices to increase adherence, and initial plausibility. Asthma patients who will be evaluated before, during, directly after, and at 2 months and 6 months after training.

For this randomized controlled treatment study, the investigators plan to compare the effects of hypoventilation-based breathing training with a control intervention that will focus on breathing regularity and awareness. The two therapeutic procedures are closely matched on important variables such as duration and the nature of patient-therapist interaction, monitoring asthma related status and the medication intake, use of scientific equipment and monitoring devices to increase adherence, and initial plausibility. Asthma patients will be evaluated before, during, directly after, and at 1 month and 6 months after training. The primary goal of this training is to determine if a capnometry-assisted breathing training to raise end-tidal CO2 will produce more improvement in asthma control than a control training of breathing awareness. The second goal is to determine if capnometry-assisted breathing training for raising pCO2 will lead to higher pCO2 levels after training than before training on all three measures of pCO2 (the 2-hour monitoring, the standardized training sessions, and the homework assignments). The last objective is to determine if the clinical improvement in asthma outcomes for the raise-pCO2 breathing group will be greater in patients with more improvement in their pCO2.

Inclusion Criteria:

1. Men or women between 18 and 65 years of age
2. Understand and read english adequately
3. A previously documented history of asthma from intermittent to severe (symptoms plus objective documentation of at least partially reversible airflow obstruction)
4. Willing to undergo a 5-session course of breathing training
5. Current asthma symptoms

Exclusion Criteria:

1. Clinically significant heart disease
2. Clinically significant cerebrovascular disease
3. Clinically significant thyroid dysfunction
4. Out-of-control diabetes
5. Use of oral corticosteroids in the last 3 months
6. Active smokers or more than 10 pack years
7. Clinically significant chronic obstructive pulmonary disease
8. Clinically significant emphysema
9. Current alcohol and substance dependence
10. Psychotic disorders and high risk for personality disorders
11. Having received previous breathing training exercises for asthma
12. Not willing to abstain from taking the morning dose of their long-term bronchodilator or leukotriene inhibitors or from using their short-acting beta-2 adrenergic agonists or anticholinergic bronchodilators for 8 hours before the pre-treatment, post-treatment, 1-month follow-up, and 6-month follow-up assessments (Medication withdrawal will be discouraged if patients should experience significant symptoms before the assessments. They will be offered to reschedule the appointment without any consequences for their enrollment in the study.)
13. Night shift workers
14. Tuberculosis
15. Pregnant, plan on becoming pregnant, or nursing during the course of the study