September 2, 2008

IMPROVING CAPILLARY CIRCULATION
WITH ELECTRICAL STIMULATION^©

Lyn Paul Taylor, A.A., B.A., M.A., R.P.T.

(Editing Assistant and Computer Consultant: Joanna Soon, B.S.)

It has long been accepted that electrical stimulation of muscle tissue to provoke muscle contractions to rhythmically squeeze associated blood vessels may be used to therapeutically improve circulation.  This process induces the muscles to artificially provide the pumping action required by nature to facilitate venous blood flow and to add impetus to lymphatic circulation.

Electrode placement for electrical stimulation of the major musculature of the calf

Less known or appreciated is the effect that electrical stimulation may have on capillary development.  Research undertaken in the late 1970's demonstrated that continuous low frequency electrical stimulation could increase capillary to muscle fiber ratio and thus the number of capillaries present in a cross-sectional area.  The formation of new capillaries may be accompanied by an increase in the total capillary surface area and the sprouting of large capillaries.  Increases in capillary density (20% after 4 days of stimulation, 50% after 14, and 100% after 28 days) are apparently not a consequence of the action of the electrical current itself.  They result from the muscular need for additional blood supply to support the demand of electrically induced muscular contractions.  Similar changes have been demonstrated to accompany hypoxia in humans and animals (non-primates) induced by endurance or aerobic exercise (repetitive isotonic contractions).  It should be noted that high frequency electrical stimulation (30 hertz and above) and isometric exercise have both failed to demonstrate the ability to increase capillary density.

Because of the ability to increase capillary density, low frequency electrical stimulation may be used to good effect when treating conditions stemming from impaired or decreased blood circulation, as in late stage diabetes.

Application:

• To increase capillary density, the electrodes may be placed in bipolar fashion (both the negative and the positive electrodes over the same muscle or muscle group) over the major musculature in the involved extremity or over musculature associated with the involved area.

• The electrical stimulator should be preset to deliver a pulsed square wave or faradic current flow at a pulse frequency of between four and 14 hertz (Hz) (six to 10 Hz would be ideal), for a 20-minute period.

• The stimulator should be turned on, and the intensity slowly increased until a visible contraction of the muscle or muscle group develops.

• As the patient gets used to the sensation of electrical stimulation, the current should be gradually increased again until the contractions are quite brisk.

• Daily treatments provide the best results.

References:

M. Brown and P.P. Gogia, "Effects of High Voltage Stimulation On Cutaneous Wound Healing in Rabbits," Physical Therapy, 67:5, May 1987. Pp. 662-667

C. Brown, O. Hudlicka, and G. Vrbova, "The Effects of Different Patterns of Muscle Activity on Capillary Density, Mechanical Properties and Structure of Slow and Fast Rabbit Muscles," Pflugers Arch., 361:241, 1979.

F.R. Clemente, D.H. Matulionis, K.W. Barron, D.P. Currier, "Effect of Motor Neuromuscular Electrical Stimulation on Microvascular Perfusion of Stimulated Rat Skeletal Muscle," Physical Therapy, 71:5, May 1991. Pp. 397-406

D.P. Currier, C.R. Petrilli and A.J. Threlkeld, "Effect of Graded Electrical Stimulation on Blood Flow to Healthy Muscle," Physical Therapy, 66:6, June 1986. Pp. 937-943

O. Hudlicka, M. Brown, M. Cotter, M. Smith, and G. Vrbova, "The Effect of Long-term Stimulation of Fast Muscles on Their Blood Flow, Metabolism and Ability to Withstand Fatigue," Pflugers Arch., 369:141, 1977.

H-I. Liu, D.P. Currier and A.J. Thelkeld, "Circulatory Response of Digital Arteries Associated with Electrical Stimulation of Calf Muscle in Healthy Subjects," Physical Therapy, 67:3, March 1987. Pp. 340-350

T. Mohr, T.K. Akers and H.C. Wessman, "Effect of High Voltage Stimulation on Blood Flow in the Rat Hind Limb," Physical Therapy, 67:4, April 1987. Pp. 526-533

R. Myrhage and O. Hudlicka, "Capillary Growth in Chronically Stimulated Adult Skeletal Muscle as Studied by Intravital Microscopy and Histological Methods in Rabbits and Rats," Mirovasc Res 16:73, 1978.

S. Salmons and F.A. Streter, "The Adaptive Response of Skeletal Muscle to Increased Use," Muscle Nerve, 4:94, 1981.

G.K. Stillwell, Therapeutic Electricity and Ultraviolet Radiation, The Williams & Wilkins Co., Baltimore, Md., 1983. Pp. 130-131

L.P. Taylor, T. Hui, The Taylor Technique of Soft Tissue Management, Inflammation: Evaluation & Treatment, 2002.  Pp. 70-72

J.E. Tracy, D.P. Currier, A.J. Threlkeld, "Comparison of Selected Pulse Frequencies from Two Different Electrical Stimulators on Blood Flow in Healthy Subjects," Physical Therapy, 68:10, October 1988. Pp. 1526-1532

D.C. Walker, D.P. Currier and A.J. Threlkeld, "Effects of High Voltage Pulsed Electrical Stimulation on Blood Flow," Physical Therapy, 68:4, April 1988. Pp. 481-485

[Back to Articles]