title: Cardiovascular responses to orthostasis and their association with falls in older adults.
abstract: BACKGROUND
  Orthostatic hypotension (OH) refers to a marked decline in blood pressure when upright. OH has a high incidence and prevalence in older adults and represents a potential intrinsic risk factor for falls in these individuals. Previous studies have not included more recent definitions for blood pressure responses to orthostasis, including initial, delayed, and recovery blood pressure responses. Furthermore, there is little research examining the relationships between cerebrovascular functioning and falling risk. Therefore, we aimed to: (i) test the association between different blood pressure responses to orthostatic stress and retrospective falling history and; (ii) test the association between cerebrovascular responses to orthostatic stress and falling history.
  
  
  METHODS
  We tested 59 elderly residents in long term care facilities who underwent a passive seated orthostatic stress test. Beat-to-beat blood pressure and cerebral blood flow velocity (CBFV) responses were assessed throughout testing. Risk factors for falls and falling history were collected from facility records. Cardiovascular responses to orthostasis were compared between retrospective fallers (≥1 fall in the previous year) and non-fallers.
  
  
  RESULTS
  Retrospective fallers had larger delayed declines in systolic arterial pressure (SAP) compared to non-fallers (p = 0.015). Fallers also showed poorer early (2 min) and late (15 min) recovery of SAP. Fallers had a greater decline in systolic CBFV.
  
  
  CONCLUSIONS
  Older adults with a positive falling history have impaired orthostatic control of blood pressure and CBFV. With better identification and understanding of orthostatic blood pressure impairments earlier intervention and management can be implemented, potentially reducing the associated risk of morbidity and mortality. Future studies should utilize the updated OH definitions using beat-to-beat technology, rather than conventional methods that may offer less accurate detection.
authors.affiliation: Department of Biomedical Physiology and Kinesiology, Simon Fraser University, British Columbia, V5A 1S6, Canada.
authors.forename: Brett H
authors.initials: BH
authors.lastname: Shaw
authors.affiliation: Department of Statistics and Actuarial Science, Simon Fraser University, British Columbia, V5A 1S6, Canada.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Loughin
authors.affiliation: Department of Biomedical Physiology and Kinesiology, Simon Fraser University, British Columbia, V5A 1S6, Canada.
authors.forename: Stephen N
authors.initials: SN
authors.lastname: Robinovitch
authors.affiliation: Department of Biomedical Physiology and Kinesiology, Simon Fraser University, British Columbia, V5A 1S6, Canada. victoria_claydon@sfu.ca.
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Claydon
mesh_terms: D000058:Accidental Falls; D000203:Activities of Daily Living / Q000145:classification; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology*; D001921:Brain / Q000098:blood supply*; D003430:Cross-Sectional Studies; D004244:Dizziness; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007024:Hypotension, Orthostatic / Q000503:physiopathology*; D008297:Male; D051346:Mobility Limitation; D012189:Retrospective Studies; D012307:Risk Factors; D013599:Systole / Q000502:physiology