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.

Cardiorespiratory response to exercise in men and women with obstructive sleep apnea.

BACKGROUND: OSA severity has been associated with self-reported lack of exercise. Most of the research has been done with men recruited from sleep clinics. There is limited data on the exercise performance of women with OSA. Therefore, the aim of this study was to assess exercise performance in a prospective, consecutive sample of men and women with OSA to compare their cardio respiratory parameters, arterial blood pressure and heart rate responses during and after exercise. METHODS: Sixty-two subjects (32 men) completed the protocol. Men had a higher peak VO2, percent predicted peak VO2, VCO2, heart rate, systolic BP, and oxygen pulse than women. RESULTS: There were no differences between men and women for peak oxygen saturation, peak Borg scales for dyspnea and leg fatigue and diastolic BP. A significant negative correlation was found between severity of OSA as measured by AHI, and peak VO2 (r=-0.4) in women, but not in men. CONCLUSION: Men with OSA have higher peak VO2 and higher peak exercise heart rate than women with OSA; they also have higher end-exercise systolic BP than women and higher SBP during recovery from exercise; although this difference is not significant when adjusted for peak systolic BP. In men with OSA, there is no correlation between peak VO2 and AHI, but there is a significant correlation between these variables in women. Heart rate and blood pressure behaved similarly during exercise in both groups.