Exercise capacity in patients with obstructive sleep apnea syndrome

Area of Science:

• Cardiology
• Pulmonology
• Sleep Medicine

Background:

• Obstructive sleep apnea syndrome (OSAS) is a prevalent condition linked to cardiovascular complications.
• Cardiovascular disturbances in OSAS contribute to increased morbidity and mortality.
• Daytime somnolence, fatigue, and hypoxemia may negatively affect exercise capacity in OSAS patients.

Purpose of the Study:

• To evaluate the cardiopulmonary response to exercise in patients diagnosed with severe OSAS.
• To investigate the relationship between sleep apnea severity and exercise limitations.

Main Methods:

• One hundred eleven middle-aged, obese patients with severe OSAS underwent overnight polysomnography.
• Symptom-limited cardiopulmonary exercise testing was conducted using the Bruce protocol on a treadmill.
• Exercise termination reasons, VO2 peak, and hemodynamic responses were analyzed.

Main Results:

• Muscle fatigue/dyspnea (66%) and hypertensive response (20%) were primary exercise termination reasons.
• While mean VO2 peak was normal, 46% of patients had VO2 peak <84% of predicted.
• Severe OSAS patients showed elevated blood pressure at rest, during exercise, and delayed recovery, correlating with apnea severity.

Conclusions:

• Exercise tolerance in OSAS patients can be limited by hypertensive responses.
• Severe OSAS is associated with exaggerated hemodynamic responses and delayed blood pressure recovery post-exercise.
• Cardiopulmonary exercise response is significantly related to the severity of obstructive sleep apnea.