LAUSR

Objective: Obstructive Sleep Apnea (OSA) via disruption of physiological sleep pattern may alter both nighttime and diurnal physical activity of untreated patients. CPAP-therapy constitutes a method of choice for moderate-to-severe OSA. Several clinical markers suggest the effectiveness of CPAP treatment incl. refreshing sleep. Whether a subjective better performance during daytime after CPAP translates into altered activity in hypertensive patients remains to be determined. The aim of the study was to assess the impact of OSA and OSA-treatment on activity patterns of hypertensive patients subjected to short-term CPAP. Design and method: 195 consecutive patients with moderate-to-severe OSA were enrolled to the study (25% female, age 58,1 ± 10.0 years; mean ± SD; BMI = 34.7 ± 5.8 kg/m2). Patients were instrumented with actigraphy recorder ACTIWATCH Philips for 7 consecutive days/nights, at baseline, and while on CPAP. Objectively assessed therapy effectiveness was based on CPAP logs i.e.: AI < 5#/hr. and median usage>4hrs per night. Results: A total of 159 patients completed the protocol. Mean actigraphy recordings lasted 6.94 and 6.53 days before, and during CPAP treatment, respectively. Several baseline actigraphic measurements correlated with PSG-derived indices i.e.: Total sleep time (Acti) vs. SpO2 (PSG) R = 0.21, P = 0.01; Sleep efficiency (Acti) vs. Mean oxygen saturation (PSG) R = 0.27, P < 0,001; Sleep efficiency (Acti) vs. T90 - oxygen saturation < 90% (PSG) R = −0.17, P = 0.04. In the subset of patients with effective CPAP there was an evident difference in daytime activity before vs. during CPAP: 14.57*103AU vs. 15.36*103AU vs. 15.36*103AU, P = 0.03, respectively; but not during nighttime P = 0.51. There was a positive relationship between increased daytime activity and severity of OSA measured as T90 (R = 0.21; P = 0.04). Patients with ineffective CPAP had similar activity at baseline, and during therapy. Conclusions: Untreated OSA affects day/night pattern of physical activity of untreated patients with hypertension, and the magnitude of desaturations best predict such dearrangement. Effective short-term CPAP appears to enhance daytime activity while the night-time activity remains intact. Whether alterations in activity patterns during CPAP play the role in cardiovascular control in OSA patients warrants further studies.