The impact of sleep duration in obstructive sleep apnea patients.

PURPOSE: Obstructive sleep apnea (OSA) is a risk factor for cardiovascular disease. Strong associations have been reported among sleep duration, hypertension, obesity, and cardiovascular mortality. The authors hypothesize that sleep duration may play a role in OSA severity. The aim of this study is to analyze sleep duration in OSA patients. METHODS: Patients who underwent overnight polysomnography were consecutively selected from the Sleep Clinic of Universidade Federal de São Paulo database between March 2009 and December 2010. All subjects were asked to come to the Sleep Clinic at 8:00 a.m. for a clinical evaluation and actigraphy. Anthropometric parameters such as weight, height, hip circumference, abdominal circumference, and neck circumference were also measured. RESULTS: One hundred thirty-three patients were divided into four groups based on total sleep time, sleep efficiency, sleep latency, and wake after sleep onset: very short sleepers (n = 11), short sleepers (n = 21), intermediate sleepers (n = 56), and sufficient sleepers (n = 45). Apnea-hypopnea index (AHI) was higher in very short sleepers (50.18 ± 30.86 events/h) compared with intermediate sleepers (20.36 ± 14.68 events/h; p = 0.007) and sufficient sleepers (23.21 ± 20.45 events/h; p = 0.02). Minimal and mean arterial oxygen saturation and time spent below 90 % oxygen saturation exhibited worse values in very short sleepers. After adjustment for gender, age, AHI, and body mass index, mean oxygen saturation was significantly associated to total sleep time (p = 0.01). CONCLUSIONS: In conclusion, the present study suggests that sleep duration may be associated to low mean oxygen saturation in OSA patients.

Exercise capacity and obstructive sleep apnea in lean subjects.

BACKGROUND: Conflicting data regarding exercise capacity and obstructive sleep apnea (OSA) have been published, which may be partially explained by the difficulty of controlling all of the confounding factors. The aim of this study is to evaluate the exercise, anthropometric, and blood parameters in lean, sedentary patients with OSA compared with controls. METHODS: Fifty-four lean subjects (including 27 patients with OSA and 27 controls) were selected. The control group was matched for age and gender. All subjects underwent polysomnography, anthropometric measures, a cardiorespiratory exercise test, two-dimensional transthoracic echocardiography, and spirometry. RESULTS: The mean age was 52.9 +/- 7.9 years in subjects with OSA and 52.8 +/- 8.1 years in controls (P = .95). The cervical circumference was greater in the lean OSA group when compared with the controls (33.7 +/- 3.5 cm vs 31.4 +/- 2.8 cm; P = .01). There were statistical differences in the apnea-hypopnea index, minimal oxygen saturation, and mean oxygen saturation in the lean patients with OSA. Glycemia was higher in the lean OSA group (115.1 +/- 50.1 mg/dL vs 94.2 +/- 9.8 mg/dL; P = .04). There were no differences between groups in the peak oxygen consumption (Vo(2)), anaerobic threshold (AT), respiratory exchange ratio (RER), BP, and heart rate. CONCLUSION: High glycemia and cervical circumference enlargement are the main characteristics of lean patients with OSA. Exercise performance is similar between groups, considering the peak Vo(2), AT, and RER. These results suggest that OSA does not impair functional capacity in lean subjects and that obesity probably participates in the diminished cardiopulmonary capacity observed in patients with OSA.

Estudo comparativo da resposta da pressão arterial e da frequência cardíaca entre exercícios isotônicos resistidos e isométricos em indivíduos hipertensos e normotensos / Comparative study of blood pressure and heart rate responses between isotonic and isometric resistance exercises in hypertensive and normotensive subjects

A monitorização da frequência cardíaca e da pressão arterial após o exercício físico é uma prática utilizada em programas de reabilitação cardiovascular. O objetivo do presente estudo foi verificar diferença nas respostas da pressão arterial e da frequência cardíaca entre exercícios físicos isotônicos resistidos e isométricos resistidos em hipertensos e normotensos...

Incremental shuttle and six-minute walking tests in the assessment of functional capacity in chronic heart failure.

BACKGROUND: The incremental shuttle test presents some theoretical advantages over the six-minute walk test in chronic heart failure (CHF), including better standardization and less dependency on collaboration. OBJECTIVES: The present study evaluated test-retest repeatability, test accuracy in predicting a peak oxygen consumption (VO(2)) of 14 mL/kg/min or less, as well as the prognostic value of both walking tests in stable CHF patients. METHODS: Sixty-three patients (44 men; New York Heart Association functional class II to IV) underwent an incremental treadmill exercise test and, on another day, the walk test in duplicate. RESULTS: Patients showed well-preserved functional capacity according to the distance walked in both tests (six-minute walk test 491+/-94 m versus incremental shuttle walk test 422+/-119 m; P<0.001). Interestingly, the six-minute and incremental shuttle walk test differences in distance walked were higher in more disabled patients. The mean bias +/-95% CI of the within-test differences were similar (7+/-40 m and 8+/-45 m, respectively). Peak VO(2), but not distance walked in either test, was associated with survival (P<0.05). CONCLUSIONS: The incremental shuttle walk test showed similar repeatability and accuracy in estimating peak VO(2) compared with the six-minute walk test in CHF patients. Direct measurement of peak VO(2), however, remains superior to either walking test in predicting survival--at least in patients with well-preserved functional capacity.

Clinical reliability of the 6 minute corridor walk test performed within a week of a myocardial infarction.

The 6 minute walk test (6 MWT) has been shown to provide a clinically useful index of functional capacity in chronic heart failure. We hypothesized that similar results would be found in patients who had a recent (ie, within a week) myocardial infarction (MI). Twenty-five patients (23 males, aged 43 to 72 years) who had undertaken an exercise stress test without complications underwent 3 consecutive 6 MWTs (1 hour apart). Heart rate, systolic and diastolic blood pressure, the level of perceived exertion (Borg scale), and the walking distance were determined. In addition, chest pain was assessed by a 0 to 10 numerical rating scale (NRS) and the ECG was continuously monitored. All subjects were able to successfully complete the exercise tests without major cardiovascular complications: mild chest pain (NRS 1 to 3) was found in 3 patients. A Bland-Altman analysis revealed that the mean bias +/- 95% confidence interval of the differences on distance walked between test 2 - test 1 were substantially higher than test 3 - test 2 differences (18 +/- 66 m and 6 +/- 41 m, respectively). The intraclass correlation coefficients were consistently high for all physiological and sensorial responses at the end of the 6 MWTs (range, 0.75 to 0.95). The 6 MWT is a safe and reproducible measurement of functional capacity in stable patients after a noncomplicated MI, even when performed within a week of the event. Therefore, this test might be useful for the evaluation of exercise tolerance in phases I and II of inpatient cardiovascular rehabilitation programs or to assess functional responses to selected interventions.

Teste graduado da caminhada (Shuttle Walk Test) na avaliação funcional de pacientes com insuficiência cardíaca crônica / Incremental shuttle walk test in the assessment of functional capacity in chronic heart failure

Objetivos: Avaliar a segurança, reprodutibilidade, a acurácia em estimar o consumo de oxigênio pico e o valor prognóstico do teste graduado da caminhada ("shuttle walk test"), em comparação com o teste da caminhada de seis minutos em pacientes com insuficiência cardíaca crônica sintomática. Métodos: Avaliamos prospectivamente 63 pacientes com insuficiência cardíaca. Todos os pacientes realizaram um teste cardiopulmonar, dois testes graduados da caminhada, dois testes da caminhada de seis minutos e foram acompanhados por um período médio de 14,01±7,8 meses. Resultados: A idade média dos pacientes foi 51,28 ± 10,26 anos, a fração de ejeção 24,05±5,69 por cento e o consumo de oxigênio pico 16,79±5,76ml/kg/min. As distâncias percorridas, no 1° e no 2° teste graduado da caminhada foram 414,44±122,87 e 422,85 ±119,18m, respectivamente, atestando sua ótima reprodutibilidade (p = 0,979). O teste mostrou-se seguro. A distância percorrida no teste graduado da caminhada foi menor em relação ao teste da caminhada de seis minutos (p < 0,001) e o índice de percepção do esforço foi maior (p = 0,029). Houve forte correlação entre as distâncias percorridas em ambos os testes (r = 0,88) e entre o teste graduado da caminhada e o consumo de oxigênio pico (r = 0,79). A acurácia em estimar um consumo de oxigênio pico menor ou igual a 14ml/kg/min foi semelhante nos dois testes. As distâncias percorridas em ambos os testes não foram preditoras de eventos e somente o consumo de oxigênio pico foi preditor de sobrevida livre de eventos. Conclusões: O teste graduado da caminhada é reprodutível, seguro e apresenta boa correlação com o teste da caminhada de seis minutos e com o consumo de oxigênio pico; mostrou-se sensível e específico em estimar um consumo de oxigênio pico inferior a 14ml/kg/min. Entretanto não foi capaz de fornecer informações sobre o prognóstico dos pacientes desta amostra.

Caderneta de orientação e controle da atividade física para reabilitação cardíaca não-supervisionada / Exercise log for control training in non-supervised home-based cardiac rehabilitation

A reabilitação cardíaca não-supervisionada é um procedimento terapêutico útil na doença coronária, contribuindo para o controle dos fatores de risco e para a melhoria da capacidade funcional. Pode ser realizada em ambulatórios, residências e logradouross públicos, com supervisão multiprofissional à distância. Seu objetivo principal é estender, sob supervisão indireta, a prática de exercícios a maior número de pacientes, de preferência considerados de baixo risco para esforço físico (Classe B, sociedade Brasileira de Cardiologia). Todavia, a reabilitação cardíaca não-supervisionada necessita de orientação e controle, com consultas periódicas e instruções teórico-práticas adequadas. É útil para o paciente receber uma caderneta, contendo os detalhes do protocolo de treinamento. O objetivo deste estudo é propor um modelo de caderneta interativa para a orientação e o controle do programa de exercícios físicos. Baseada no AHA Scientific Statement (2001) e no I Consenso Nacional Reabilitação Cardiovascular (1997), vem sendo utilizada no ambulatório de reabilitação cardíaca não-supervisionada da Escola Paulista de Medicina...