Factors affecting continuous beat-to-beat orthostatic blood pressure response in community-dwelling older adults

To examine the effect of age, time of day, the timing of medication and food ingestion on orthostatic blood pressure response (OBP) in community-dwelling adults.

A nationally representative sample of 109 community-dwelling adults aged at least 50 years attended for health assessment in a pilot study of The Irish Longitudinal Study on Ageing. OBP was measured using continuous beat-to-beat plethysmography (Finometer) during active stand, and OBP with excessive artefacts were excluded. Nine outcome variables were supine systolic blood pressure (SBP), lowest standing SBP (nadir), standing SBP at 40, 60 and 120 s and the difference in supine SBP and nadir (delta SBP) and delta at 40, 60 and 120 s. Factors included for multiple linear regression analysis were age, time of assessment, interval from the last meal and whether regular medications were taken on the day. Subgroup analysis was performed on 103 respondents who were not on β-blocker, fludrocortisone and Parkinson medications.

There were 53 men, mean age 62.1 (SD=9.4) years. Older respondents (≥60 years) showed greater delta at 40 s by up to 12.9 mmHg. Delta SBP and delta 40, 60 and 120 were not significantly affected by the time of day or food ingestion. The effect of medications on delta 40 was no longer present in subgroup analysis.

Age was the most significant determinant of OBP and was most strongly associated with greater delta at 40 s. This was independent of the time of day, food and medication ingestion. Continuous beat-to-beat plethysmography provides for a window into the pattern of OBP in community-dwelling adults aged 50 years and older.