Effect of local vibrations with different exposure times on skin blood flow in diabetes

One of the most serious complications of poorly treated diabetes is diabetic foot syndrome. It appears as the presence of an infected ulcer (wound) with features of neuropathy and impaired blood flow, which are not only the most important pathological factors leading to the formation of a foot ulcer, but also responsible for the deterioration of the ulcer. In the light of reports of improved blood flow by therapeutic vibrations, scientists from the University of Beihang (China) decided to investigate the effect of short-term local vibration of various durations on plantar skin blood flow (SBF) in healthy and diabetic subjects.

• In diabetic patients, local intermittent vibrations (LIV1 and LIV2) significantly increased SBF during and after the administration of vibrations, while local continuous vibrations (LCV) did not induce changes in SBF.
• In healthy subjects, all vibration interventions (LIV1, LIV2, LCV) significantly increased SBF during administration of vibrations and up to 90 s after administration.

Prepared on the basis of:

Effects of Local Vibration With Different Intermittent Durations on Skin Blood Flow Responses in Diabetic People. Ren W, Pu F, Luan H et al. (2019). Front. Bioeng. Biotechnol. 7:310.

Study population

11 patients with diabetes (7 men) and 15 healthy adults (6 men) participated in the experiment.

Test procedure

Local continuous vibration (LCV) or two intensities of local intermittent vibration (LIV1 and LIV2) were delivered to the middle metatarsal head of the right foot. SBF was measured before, during and after the administration of the vibrations.

A laser Doppler flowmeter (PeriFlux 5001, Perimed, Sweden) was used to measure the SBF of the metatarsus. During the examination, it was placed on the skin through the hole of the vibration head cylinder.

Use of vibration in the study

The vibration was provided by a specially designed device, consisting of a motor, a vibration head in the form of a cylinder, a control module, a power supply, a platform and a support frame for the feet and calves. The frequency of vibrations was set at 50 Hz, the amplitude at 2 mm.

Time parameters of vibrotherapy protocols:

• LCV – continuous vibration for 5 minutes
• LIV1 – 10 s of vibration followed by a 5 s pause for a total duration of 7.5 minutes.
• LIV2 – 10 s of vibration followed by a 10 s pause for a total of 10 minutes.

The total vibration time for all 3 protocols was 5 minutes.

Results

In diabetic patients, LIV1 and LIV2 significantly increased SBF during and after administration of vibrations, while LCV did not induce changes in SBF.

In healthy subjects, all vibration interventions significantly increased SBF during administration of the vibration and in the first 90 s after administration of the vibration.

Comment

In the presented report it was observed that intermittent vibrations can significantly increase SBF in both diabetic and healthy subjects. Continuous vibration, on the other hand, may not be effective in diabetics. Moreover, increasing blood circulation by vibrations was much less effective in diabetics than in healthy subjects. This may confirm the presence of a vessel’s  pathological condition in diabetes, where impaired microcirculation may be responsible for the impaired response to vibrations.

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