Effect of vibration (30 or 50 Hz) on skin blood flow in the arm

The studies conducted so far show that whole-body vibration increas skin blood flow (SBF). However, there are no studies comparing the effectiveness of different vibration parameters. Therefore, American scientists from Loma Linda University decided to test the effect of vibrations of different frequencies on SBF.

• Both the 30 Hz and 50 Hz vibrations applied to the arm for 5 minutes significantly raised the SBF of the arm.
• This elevated SBF level was maintained for at least 9 minutes.
• 50 Hz vibrations increased SBF faster than 30 Hz vibrations.
• During the 15-minute rest phase after vibration, SBF remained elevated after 50 Hz vibration, while a decrease in SBF was observed after 30 Hz vibration.

Prepared on the basis of:

The effect of 30 Hz vs. 50 Hz passive vibration and duration of vibration on skin blood flow in the arm. Maloney-Hinds C, Petrofsky JS, Zimmerman G. Med Sci Monit. 2008 Mar;14(3):CR112-6.

Test procedure

Two studies were carried out. The first one was attended by 18 people (age: 20.3 ± 2.9 years), randomly assigned to receive vibrations of 30 or 50 Hz. The second study involved 7 people (age: 23.3 ± 3.8 years) who were given both 30 Hz and 50 Hz vibrations.

Vibrations were delivered to the arm for 10 minutes using the Power Plate® platform (Culver City, USA). A vibration amplitude of 5-6 mm was used.

At the end of each minute of vibration delivery, the vibration was stopped for 10 seconds to take a SBF measurement. SBF was also measured during 15 minutes of rest after vibration.

Results

Both tested vibration frequencies (30 or 50 Hz) significantly increased SBF (p <0.05) in the first 4 minutes of vibration, reaching peak SBF in the 5th minute. SBF was high from 4th to 10th minute of vibration. During the rest phase, the 30 Hz vibrations produced SBF below baseline, while the 50 Hz vibrations resulted in increased SBF.

The observed increase in SBF after vibrations of 50 Hz tended to exceed the increase after  30 Hz vibrations, however, due to the large diversity, the effects of both tested frequencies were not statistically significantly different from each other.

Comment

Five minutes of 30 or 50 Hz vibration significantly increases SBF. Clinically, 50 Hz vibration may be preferable because it causes a faster increase in SBF and does not induce vasoconstriction during the rest period after the vibration. Future research should focus on determining whether these increases in SBF may be of benefit to those with reduced circulation.

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