Main objective: To assess the effect of the daily physical activity promotion with a pedometer during 12 months on the apnea-hypopnea index (AHI) in patients with mild to moderate obstructive sleep apnea (OSA).

Study patients. Subjects 30-80 years old with diagnosis of mild-moderate OSA (AHI: 5-30 and predominance of obstructive events [>80%)].

Design. Randomized, parallel and open-label clinical trial, controlled with conventional treatment.

Intervention: Patients will be randomized (1:1) to control group [treatment and follow-up according to conventional clinical practice] or intervention group [in addition to conventional treatment and follow-up, the patients will receive a pedometer to measure the number of steps walked daily. Based on the cumulative step count for each day and the mean value since the last visit, patients will receive a task to increase their steps per day by the next appointment according to the next protocol (<6000 steps/day: increase by 3000 steps/day; 6000 - 10000 steps/day: reach 10000 steps/day; and > 10000 steps/day: maintain or increase steps).

Measurements. At , 12, 24 and 52 weeks of randomization, the following determinations will be made: anthropometric characteristics; clinical evaluation (smoking history, sleep symptoms, comorbidities, current medication); questionnaires (ESS, FOSQ, SF-12, EuroQoL and iPAZ); heart rate and blood pressure; analytical determinations (HbA1c, HOMA index, cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, homocysteine, NT-proBNP and hsCRP); plasmatic biomarkers (8-isoprostane, IL1beta, IL6, IL8 and TNFalpha); and evaluation of daily physical activity using an accelerometer.](streamdown:incomplete-link)

Inclusion Criteria:

• Age from 30 to 80 years
• Diagnosis of mild-moderate obstructive sleep apnea [apnea-hypopnea index 5-30 h-1] by polysomnography or respiratory polygraphy
• Predominance of obstructive events (> 80%)
• Signature of informed consent

Exclusion Criteria:

• Previous diagnosis of chronic obstructive pulmonary disease, asthma, diffuse interstitial lung disease or chest wall disease.
• Evidence of central apneas, hypoventilation syndrome or respiratory failure
• Previous diagnosis of refractory arterial hypertension, congestive heart failure, ischemic heart disease or cerebro-vascular disease.
• Neurological or osteoarticular limitation that prevents ambulation.
• Professional drivers or occupational risk or respiratory
• Previous treatment with CPAP
• Participation in another clinical trial in the 30 days prior to randomization.