Characteristics of cardiovascular responses to an orthostatic challenge in trained spinal cord-injured individuals

Journal of Physiological Anthropology

Masako Yamaoka Endo¹  Masahiro Itoh²  Yoshiyuki Fukuoka³  Tatsuya Hojo⁴  Miho Yoshimura⁴ 

[1] Department of Exercise Science and Physiology, Faculty of Human Culture and Science, Prefectural University of Hiroshima;Department of Physiology, Kumamoto University Graduate School of Life Sciences;Laboratory of Environmental Physiology, Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto;Laboratory of Sports Medicine, Faculty of Health and Sport Science, Doshisha University;

关键词: Orthostatic challenge;    Spinal cord injury;    Cardiovascular responses;    Near-infrared spectroscopy;   

DOI  :  10.1186/s40101-018-0182-x

来源: DOAJ

【 摘 要 】

Abstract Background We investigated cardiovascular responses to an orthostatic challenge in trained spinal cord-injured (SCI) individuals compared to able-bodied (AB) individuals. Methods A total of 23 subjects participated, divided into three groups: seven were trained as spinal cord-injured (Tr-SCI) individuals, seven were able-bodied individuals trained as runners (Tr-AB), and nine were untrained able-bodied individuals (UnTr-AB). We measured the cardiovascular autonomic responses in all three groups during each 5-min head-up tilt (HUT) of 0°, 40°, and 80°. Stroke volume (SV), heart rate (HR), and cardiac output (Qc) as cardiovascular responses were measured by impedance cardiography. Changes in deoxyhemoglobin (∆[HHb]) and total hemoglobin (∆[Hbtot]) concentrations of the right medial gastrocnemius muscle were measured using near-infrared spectroscopy (NIRS). Results As the HUT increased from 0° to 80°, Tr-SCI group showed less change in SV at all HUT levels even if HR increased significantly. Mean arterial pressure (MAP) also did not significantly increase as tilting increased from 0° to 80°. Regarding peripheral vascular responses, the alterations of ∆[Hbtot] from 0° to 80° were less in Tr-SCI group compared to AB individuals. Conclusion There is a specific mechanism whereby blood pressure is maintained during a HUT in Tr-SCI group with the elicitation of peripheral vasoconstriction and the atrophy of the vascular vessels in paraplegic lower limbs, which would be associated with less change in SV in response to an orthostatic challenge.

【 授权许可】

Unknown