Effect of topical menthol on ipsilateral and contralateral superficial blood flow following a bout of maximum voluntary muscle contraction

Various doses of topical menthol are commonly applied prior to, during, and after exercise to relieve pain although there is limited empirical evidence examining the physiological effects of this treatment. The purpose of this study was to examine the effects of two different doses of menthol (3.5% and 10%) on blood flow and arterial diameter before and after an acute bout of three isokinetic maximum voluntary muscular contraction (MVMC) of the quadriceps and hamstrings. Blood flow and arterial diameter of the right and left popliteal arteries were measured with an ultrasound Doppler prior to and after subjects completed 1 set of 3 MVMC isokinetic knee extension/flexion exercises. Immediately following this exercise one of three different treatment conditions was randomly applied to the right thigh only; 3.5% menthol gel, 10% menthol wipe, or a control condition. Five minutes following the treatment application blood flow through both right and left popliteal arteries was reassessed. This procedure was completed once per week until each of the 16 subjects was exposed to each treatment condition. Repeated measures ANOVA with post hoc analysis indicated that both menthol dosages resulted in significant decreases in popliteal blood flow on the right (-19.60 to -8.39%) and left sides (-14.72 to -5.4%) while the control condition demonstrated an increase in blood flow bilaterally (+26.40 to +15.19%) as a result of the MVMC exercise. The right popliteal arterial diameter was also significantly reduced as a result of both menthol dosages (-5.73 to -6.73%) and increased under the control condition (+6.67%). These results indicate that topical menthol has a rapid effect on reducing ipsilateral and contralateral arterial blood flow as well as ipsilateral arterial diameter. 2a.