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Knee‐high compression socks minimize head‐up tilt‐induced cerebral and cardiovascular responses following dynamic exercise
Author(s) -
Dorey T. W.,
O'Brien M. W.,
Robinson S. A.,
Kimmerly D. S.
Publication year - 2018
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.13084
Subject(s) - medicine , supine position , blood pressure , blood volume , cardiology , anesthesia , population , transcranial doppler , environmental health
In healthy individuals during a non‐exercised state, knee‐high compression socks ( CS ) may reduce the magnitude of lower limb venous pooling during orthostasis but are not effective at minimizing the incidence of pre‐syncopal symptoms. However, exaggerated reductions in cerebral blood flow velocity ( CBV ) and cardiac stroke volume ( SV ) occur during passive head‐up tilt ( HUT ) testing following dynamic exercise. It is unknown if CS can minimize post‐exercise HUT ‐induced decrements in CBV and SV in this population. To test the hypothesis that CS will attenuate the reductions in SV and CBV during 60° HUT following 60 minutes of moderate‐intensity (60% VO 2 peak) cycling exercise. Ten healthy volunteers (22.6 ± 2.1 years, 24.1 ± 2.5 kg/m 2 ) completed pre‐ and post‐exercise 15‐minute HUT tests during randomized CS and Control (no CS ) conditions. Changes in blood pressure (finger plethysmography), SV (Modelflow® method), and CBV (Transcranial Doppler) were measured during HUT and preceding supine rest periods. Pre‐exercise HUT ‐induced similar (all, P > .47) reductions in SV (Control; −23.1 ± 11.5%, CS ; −20.5 ± 10.9%) and CBV (Control; −18.1 ± 6.3%, CS ; −15.3 ± 9.0%). However, larger post‐exercise decreases in SV and CBV during HUT were observed in the Control versus CS condition. Specifically, CS attenuated the drop in SV (Control: −32.9 ± 5.6%, CS : −24.3 ± 11.6%; P = .01) and CBV (Control: −25.1 ± 5.8%, CS : −17.6 ± 7.8%; P = .02) during the post‐exercise HUT test. These results indicate that CS attenuated HUT ‐induced reductions in SV and CBV following moderate‐intensity cycling exercise and suggest that CS may be an effective countermeasure to reduce the incidence of post‐exercise syncope in vulnerable populations.