OBJECTIVE: There are several treatments for obstructive sleep apnea syndrome, such as weight loss, use of an oral appliance and continuous positive airway pressure, that can be used to reduce the signs and symptoms of obstructive sleep apnea syndrome. Few studies have evaluated the effectiveness of a physical training program compared with other treatments. The aim of this study was to assess the effects of physical exercise on subjective and objective sleep parameters, quality of life and mood in obstructive sleep apnea patients and to compare these effects with the effects of continuous positive airway pressure and oral appliance treatments. METHODS: Male patients with moderate to severe obstructive sleep apnea and body mass indices less than 30 kg/m2 were randomly assigned to three groups: continuous positive airway pressure (n = 9), oral appliance (n = 9) and physical exercise (n = 7). Polysomnographic recordings, blood samples and daytime sleepiness measurements were obtained prior to and after two months of physical exercise or treatment with continuous positive airway pressure or an oral appliance. Clinicaltrials.gov: NCT01289392 RESULTS: After treatment with continuous positive airway pressure or an oral appliance, the patients presented with a significant reduction in the apnea-hypopnea index. We did not observe changes in the sleep parameters studied in the physical exercise group. However, this group presented reductions in the following parameters: T leukocytes, very-low-density lipoprotein and triglycerides. Two months of exercise training also had a positive impact on subjective daytime sleepiness. CONCLUSIONS: Our results suggest that isolated physical exercise training was able to modify only subjective daytime sleepiness and some blood measures. Continuous positive airway pressure and oral appliances modified the apnea-hypopnea index.

FUNDAMENTO: O teste de exercício de 4 segundos (T4s) avalia o tônus vagal cardíaco durante o transiente inicial da frequência cardíaca (FC), em exercício dinâmico súbito, por meio da identificação do índice vagal cardíaco (IVC) obtido a partir do eletrocardiograma (ECG). OBJETIVO: Testar a utilização do monitor de frequência cardíaca (MFC) Polar S810 como recurso alternativo ao ECG na aplicação do T4s. MÉTODOS: Neste trabalho, 49 indivíduos do sexo masculino (25 ± 20 anos, 176 ± 12 cm, 74 ± 6 kg) realizaram o T4s. Os intervalos RR foram registrados simultaneamente por ECG e MFC. Calcularam-se média e desvio padrão do último intervalo RR do período pré-exercício ou o primeiro do período de exercício, aquele que for mais longo (RRB), do mais curto intervalo RR do período de exercício (RRC) e do IVC obtidos por ECG e MFC. Utilizou-se o teste t de Student para amostras dependentes (p < 0,05) para testar a significância das diferenças entre as médias. Para identificar a concordância entre o ECG e o MFC, utilizou-se a regressão linear, com cálculo do coeficiente de correlação de Pearson e a estratégia proposta por Bland e Altman. RESULTADOS: A regressão linear apresentou r² de 0,9999 para o RRB, 0,9997 para o RRC e 0,9996 para o IVC. A estratégia de Bland e Altman apresentou desvio padrão de 0,92 ms para o RRB, 0,86 ms para o RRC e 0,002 para o IVC. CONCLUSÃO: O MFC Polar S810 se mostrou eficiente na aplicação do T4s quando comparado ao ECG.

BACKGROUND: The 4-second exercise test (T4s) evaluates the cardiac vagal tone during the initial heart rate (HR) transient at sudden dynamic exercise, through the identification of the cardiac vagal index (CVI) obtained from the electrocardiogram (ECG). OBJECTIVE: To evaluate the use of the Polar S810 heart rate monitor (HRM) as an alternative resource to the use of the electrocardiogram in the 4-second exercise test. METHODS: In this study, 49 male individuals (25 ± 20 years, 176 ±12 cm, 74 ± 6 kg) underwent the 4-second exercise test. The RR intervals were recorded simultaneously by ECG and HRM. We calculated the mean and the standard deviation of the last RR interval of the pre-exercise period, or of the first RR interval of the exercise period, whichever was longer (RRB), of the shortest RR interval of the exercise period (RRC), and of the CVI obtained by ECG and HRM. We used the Student t-test for dependent samples (p < 0.05) to test the significance of the differences between means. To identify the correlation between the ECG and the HRM, we used the linear regression to calculate the Pearson's correlation coefficient and the strategy proposed by Bland and Altman. RESULTS: Linear regression showed r² of 0.9999 for RRB, 0.9997 for RRC, and 0.9996 for CVI. Bland e Altman strategy presented standard deviation of 0.92 ms for RRB, 0.86 ms for RRC, and 0.002 for CVI. CONCLUSION: Polar S810 HRM was more efficient in the application of T4s compared to the ECG.

FUNDAMENTO: El test de ejercicio de 4 segundos (T4s) evalúa el tono vagal cardíaco durante el transiente inicial de la frecuencia cardíaca (FC), en ejercicio dinámico súbito, por medio de la identificación del índice vagal cardíaco (IVC) obtenido a partir del electrocardiograma (ECG). OBJETIVO: Probar la utilización del monitor de frecuencia cardiaca (MFC) Polar S810 como recurso alternativo al ECG en la aplicación del T4s. MÉTODOS: En este trabajo, 49 individuos del sexo masculino (25 ± 20 años, 176 ±12 cm, 74 ± 6 kg) llevaron el T4s. Los intervalos RR fueron registrados simultáneamente por ECG y MFC. Se calcularon el promedio y la desviación estándar del último intervalo RR del período pre ejercicio o el primer del período de ejercicio, aquel que fuera más largo (RRB), del más corto intervalo RR del período de ejercicio (RRC) y del IVC obtenidos por ECG y MFC. Se utilizó la prueba t de Student para muestras dependientes (P < 0,05) para probar la significancia de las diferencias entre los promedios. Para identificar la concordancia entre el ECG y el MFC, se utilizó la regresión lineal, con cálculo del coeficiente de correlación de Pearson y la estrategia propuesta por Bland y Altman. RESULTADOS: La regresión lineal expresó r² de 0,9999 para el RRB, 0,9997 para el RRC y 0,9996 para el IVC. La estrategia de Bland y Altman expresó desviación estándar de 0,92 ms para el RRB, 0,86 ms para el RRC y 0,002 para el IVC. CONCLUSIÓN: El MFC Polar S810 se halló eficiente en la aplicación del T4s cuando comparado al ECG.