- Effects of Spinal Cord Injury on Heart Rate Variability and Blood Pressure Variability

The incidence rate of spinal cord injury (SCI) varies widely across different parts of the world. While the incidence rate is estimated at 35 per million in Canada, in the United States, the incidence rate is estimated at 50 per million per year (Sekhon and Fehlings, 2001). While these incidence rates seem relatively small, they translate to approximately 1,100 new injures in Canada and approximately 12,000 new injuries in the United States each year (Rick Hansen Foundation, 2010), numbers that are added to the estimated 41,000 CONTENTS 19.1 Introduction ........................................................................................................................ 371 19.2 Cardiovascular Disease and Dysfunction after SCI ..................................................... 372 19.3 Measures of Autonomic Regulation of the Cardiovascular System ........................... 378 19.3.1 HRV as an Index of Autonomic Control of the Heart ...................................... 378 19.3.2 HRV as a Predictor of Cardiovascular Risk ....................................................... 379 19.3.3 Neurovascular Control .........................................................................................380 19.3.4 BPV as an Index of Neurovascular Control .......................................................380 19.3.5 BPV and Risk of Cardiovascular Disease ........................................................... 381 19.4 Effects of SCI on Measures of HRV and BPV ................................................................ 382 19.4.1 HRV in Individuals with SCI ............................................................................... 382 19.4.1.1 Debating the Presence or Absence of the LF Component after SCI .................................................................................................. 382 19.4.1.2 Validity and Reliability of HRV Measures after SCI .........................384 19.4.2 Effects of Exercise Training on HRV: Comparisons between Able-Bodied Population and SCI Population ....................................................386 19.4.3 BPV in Individuals with SCI ................................................................................388 19.4.4 Effects of Exercise Training on BPV: Comparisons between Able-Bodied Population and SCI Population ............................................................................ 389 19.5 Discussion ........................................................................................................................... 390 19.6 Future Research ................................................................................................................. 390 19.7 Conclusions ......................................................................................................................... 391 Acknowledgments ...................................................................................................................... 391 Abbreviations .............................................................................................................................. 391 References ..................................................................................................................................... 392 Canadians and 306,000 Americans already living with an SCI. Globally, there are 223-755 million individuals living with an SCI, a number that increases annually by 10.4-83 million individuals (Wyndaele and Wyndaele, 2006).