Maria, age 48, was recently diagnosed with moderate obstructive sleep apnea. Her clinician recommends a program of caloric restriction and regular aerobic activity in addition to CPAP therapy because:

• A. improved cardiovascular fitness directly cures upper-airway collapse.
• B. lowering body mass reduces soft-tissue pressure around the throat and can lessen airway obstruction.
• C. weight loss eliminates the risk of developing central apneas.
• D. increased daytime activity alone will normalize nocturnal breathing patterns.

Answer: (B)