The EXERCISE group will participate in an aerobic exercise program for 12 weeks, performed in intensity relative to 50% of reserve heart rate, on a treadmill.

Polysomnographic recording included an electroencephalogram, an electrooculogram, an electromyogram, and an electrocardiogram. Measurements of air flow (oral and nasal), respiratory effort (thoracic and abdominal), body movement, and oxygen saturation were also taken. The measured variables included total sleep time, sleep efficiency (ratio between total sleep time and total recorded time multiplied by 100), sleep onset latency, wake after sleep onset, arousals, sleep stages (N1, N2 and N3 non-rapid eye movement [non-REM] sleep and REM sleep), latencies for each sleep stage. Two researchers who were blinded to the study design performed the staging and analysed the polysomnographic events using international criteria

Prior sleep state anxiety will be assessed with the State-Trait Anxiety Inventory-STAI,25 the Portuguese version of which was validated by Gorenstein and Andrade.26 This scale encompasses 20 items and provides a one-dimensional measurement of anxiety. The volunteers were instructed to answer it 30 minutes before going to sleep at baseline and at the post-exercise evaluation.

The POMS questionnaire is an instrument to evaluate the acute profile of mood. It has 65 items and 6 domains: tension-anxiety, depression, anger-hostility, vigour-activity, fatigue, and confusion- bewilderment. The total mood disturbance score is derived by subtracting the vigour-activity score from the the sum of scores from the other subscales

The PSQI assesses sleep quality over a 1-month period. The questionnaire consists of 19 self-rated questions and 5 questions that should be answered by bedmates or roommates. The latter questions are used only for clinical information. The 19 questions are categorized into 7 components, graded on a score that ranges from 0 to 3. The PSQI components are as follows: subjective sleep quality (C1), sleep latency (C2), sleep duration (C3), habitual sleep efficiency (C4), sleep disturbances (C5), use of sleeping medication (C6) and daytime dysfunction (C7). The sum of scores for these 7 components yields one global score, which ranges from 0 to 21, where the highest score indicates worst sleep quality. A global PSQI score greater than 5 indicates major difficulties in at least 2 components or moderate difficulties in more than 3 components.

The blood sample will be collected at 8a.m. The serum serotonin dosage will be made by high performance liquid chromatography (HPLC)