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Ultrasonic bone stimulation increases orthostatic tolerance after 24 hours of bed rest (1171.6)
Author(s) -
Ray Chester,
Sauder Charity,
Dyckman Damian
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.1171.6
Subject(s) - orthostatic vital signs , medicine , stimulation , blood pressure , anesthesia , heart rate , orthostatic intolerance , bed rest , cardiology
Our studies indicate that stimulation of the otolith organs by gravitational (head‐down rotation) and non‐gravitational (ultrasonic bone stimulation of mastoid; UBS) activation increases muscle sympathetic activity in humans. These findings suggest that otolith stimulation might assist in maintaining vascular resistance and arterial blood pressure during orthostatic challenges. To test this hypothesis, 16 subjects were placed in head‐down bed rest for 24 hours and then tested twice with an 80° head‐up tilt test once with and without UBS. The order of the two tilt tests was randomized with a maximum test duration of 30 min. Eight subjects were able to complete both tests after bed rest. In the remaining 8 subjects (2 M, 6 F, 26 ± 2 yr, 172.4 ± 3.0 cm, 74.6 ± 5.8 kg) who could not complete the tilt tests, tilt time was significantly greater in 7 of the 8 subjects with UBS compared to without (743 ± 180 vs. 574 ± 158 s, P = 0.002). Mean arterial pressure was 60±6 mmHg at the stoppage of the control tilt test and 90±5 mmHg at the same time point during UBS trial (P = 0.006). However, heart rate was unaffected by UBS during head‐up tilt (95 ± 5 and 93 ± 11 bpm for UBS and control, respectively). These findings indicate that UBS can improve orthostatic tolerance in subjects following bed rest. Similar results might be expected in subjects that experience orthostatic intolerance due to other reasons. Grant Funding Source : Supported by NIH (HL109952), NSBRI (CA00404)