OVERNIGHT FLUID SHIFT IN SLEEP APNEA AND STROKE: DOES BEING PHYSICALLY ACTIVE MATTER?

C. Frange¹, C. Siengsukon², R.M. Elias^3,4, B.J. Murray^5,6, F.M.S. Coelho^1,7

Background: Obstructive sleep apnea (OSA) and physical inactivity frequently occur following stroke. Physical inactivity can lead to edema or exacerbate edema following stroke, and the resultant overnight fluid shift may increase the risk of OSA.

Purpose: The purpose of this study was to investigate the effect of physical activity on fluid shift redistribution and its impact on OSA, sleep pattern and edematous state of hemiparetic stroke patients.

Methods: In 7 patients post first-ever ischemic stroke at subacute phase (3-6 months), we measured change in apnea-hypopnea index (AHI) and sleep parameters measured during 2 polysomnography exam (PSG). Neck circumference (tape measure at cricoid cartilage), and arms, legs and trunk (thorax, abdomen and pelvis) fluid volume (multifrequency bioelectrical impedance spectrum analyzer) were measured before and after PSG. The PSGs were performed after 1-day of being inactive (sitting/lying) at the lab, and again after performing physical activity (standing, walking, climbing stairs and calf exercise for 30 mins/hour) for 1-day under PTs supervision. Physical activity has ended 2 hours before to PSG. Data analysis was performed using SPSS version 20.0 (SPSS Inc., Chicago, IL, USA). Each subject served as their own control. Nonparametric tests were used (Wilcoxon test or Friedman test) for changes in fluid volumes, neck circumference and sleep parameters were compared by paired when appropriate. The parameter variation of fluid redistribution (Δ) is the change between the two nights, defined by variables in the physical active condition night minus variables in the physical active condition night. Data are presented as mean±SD or percentage, when appropriate. Level of significance was set as p<0.05.

Results: No statistical significance was found for AHI when comparing inactivity and activity (inactive: 16.9/h vs. active: 12.3/h, Z=-1.57, p=0.12), despite the clinical significance of this finding. REM sleep stage statistically significant decreased (Z=-2.03, p<0.05); increased fluid volume in trunk (X2=7.00, p<0.01), and paretic arm (X2=7.00, p<0.01). Combined, sleep and acute physical activity statistically significant increased fluid volume in the trunk (X2=7.00, p<0.01), and in the paretic arm (X2=7.00, p<0.01). The variation of fluid volume in the paretic arm was statistically significantly lower in the physically active condition compared to inactivity (Z=-2.37, p<0.05).

Conclusion(s): Being physically active for just one day did not change AHI significantly, but clinically changed from moderate to mild OSA. Acute physical activity decreased REM sleep stage and prevented fluid accumulation in the paretic arm. Reducing inactivity and increasing physical activity in patients following stroke may be a promising intervention to reduce OSA and ameliorate functional recovery.

Implications: Breaking up inactivity and increasing physical activity in patients following stroke may be a promising intervention to reduce OSA severity and ameliorate functional recovery of paretic arm. Our investigation support physical activity as an evidence-based intervention to improve objective metrics of sleep in patients following stroke.

Funding, acknowledgements: São Paulo Research Foundation (FAPESP, grant #2018/18952-1).

Keywords: obstructive sleep apnea, physical activity, stroke

Topic: Health promotion & wellbeing/healthy ageing/physical activity

Did this work require ethics approval? Yes

Institution: UUniversidade Federal de São Paulo

Committee: UNIFESP, #1469/2018

Ethics number: CAAE #04393318.8.0000.5505