This study evaluates the intervention of the 1) sodium-restricted diet, or 2) diuretic, or 3) placebo pill in the treatment of obstructive sleep apnea in adults.

Men with apnea-hypopnea index greater than 30/hour will be included and randomly assigned into three groups: sodium-restricted diet, or diuretic, or control. The intervention will last one week. The diuretic group will receive combined spironolactone 100mg plus furosemide 20mg daily. The diet group will receive a regimen with a maximum intake of three grams of sodium per day. The control group will receive a placebo pill and will maintain all eating habits.

Inclusion Criteria:

• Men in the age range from 18 to 60 years
• Full-night in-laboratory polysomnography with apnea-hypopnea index > 30/h in the last three months
• Body mass index < 35 kg/m2
• Informed consent

Exclusion Criteria:

• Already having started any treatment for sleep apnea, including use of continuous positive airway pressure
• NYHA heart failure, any class
• Predominantly central apnea
• Peripheral venous or lymphatic insufficiency
• Any chronic renal disease
• Use of diuretics and substances with action in the central or peripheral nervous system such as benzodiazepines, hypnotics, anticonvulsants, antidepressants, appetite suppressants, amphetamines, antiparkinson agents, muscle relaxants, bronchodilators
• Stroke within 6 months or with incapacitating sequelae
• Any physical, mental or social condition impairing the ability to participate in the trial