Increased skin blood flow during low intensity vibration in human participants: Analysis of control mechanisms using short-time Fourier transform.

Aim: Investigate the immediate effect of low intensity vibration on skin blood flow and its underlying control mechanisms in healthy human participants.
Materials and Methods: One-group pre-post design in a university laboratory setting. Nine adults underwent two bouts of 10-minute vibration (30Hz, peak acceleration 0.4g). Outcome measures include skin blood flow, and skin temperature on the right foot. To examine the control mechanisms underlying the vibration-induced blood flow response, SHORT-TIME Fourier analyses were computed to obtain the spectral densities for three frequency bands: metabolic (0.0095-0.02Hz), neurogenic (0.02-0.06Hz), and myogenic (0.06-0.15Hz). Non-parametric Friedman's tests were computed to compare changes of the outcome measures and control mechanisms over the course of vibration.
Results: Vibration increased skin blood flow during both bouts of vibration, however the effect did not last after vibration was terminated. Myogenic spectral density increased during both bouts of vibration, whereas the metabolic and neurogenic spectral densities increased only during the 2nd bout of vibration. Interestingly, only the metabolic spectral density remained elevated after vibration ended.
Conclusion: Low intensity vibration produced acute increases in skin blood flow mediated in part by vascular control mechanisms of myogenic origin. Further investigation is warranted to determine whether low intensity vibration induces similar increases in skin blood flow in populations prone to developing chronic non-healing wounds, such as spinal cord injury and diabetes.
Competing Interests: The author of this manuscript (Koh) has the following competing interest: patent pending on the application of vibration for therapeutic treatment. The name for the pending patent is, “Method and system for physical stimulation of tissue” (#2013/0165,824). This does not alter our adherence to PLOS ONE policies on sharing data and materials.