FIRST STAGE (Healthy volunteers)  Inclusion Criteria:  Age between 20 and 40 years old Living in the city of São Paulo, Brazil No physical or intellectual disability that prevent attending to a in-lab polysomnography or understanding its instructions.  Exclusion Criteria:  Excessive daytime sleepiness (as measured by the Epworth Sleepiness Scale) Poor sleep quality (as measured by the Pittsburgh Sleep Quality Index) Insomnia symptoms at any level (as measured by the Insomnia Severity Index) Symptoms of depression (as measured by the Beck Depression Inventory) High risk to sleep apnea (as measured by the Stop-Bang questionnaire) Presence of sleep-related symptoms (as measured by the UNIFESP (Federal University of São Paulo sleep questionnaire) Self-reported abuse of alcohol, use of abuse drugs or use of medicine that might impact the normal sleep pattern (including hypnotics, benzodiazepines, antidepressants, corticosteroids, etc). Self-reported chronic diseases Diagnosis of any sleep disorders during the polysomnography  SECONDS STAGE (volunteers with sleep disorders or complaints)  Inclusion Criteria:  Age between 20 and 40 years old Living in the city of São Paulo, Brazil No physical or intellectual disability that prevent attending to a in-lab polysomnography or understanding its instructions. At least one sleep disorder or sleep complaint. . Among these, at least 30% of the sample should have moderate to severe insomnia (as measured by the insomnia severity index), 30% should have high risk to sleep apnea (as measured by the STOP-BANG questionnaire) and 70% should have excessive sleepiness scale (as measured by the Epworth sleepiness scale).  Exclusion criteria:  Absence of sleep disorders.