title: Topical menthol, ice, peripheral blood flow, and perceived discomfort.
abstract: BACKGROUND
  Injury management commonly includes decreasing arterial blood flow to the affected site in an attempt to reduce microvascular blood flow and edema and limit the induction of inflammation. Applied separately, ice and menthol gel decrease arterial blood flow, but the combined effects of ice and menthol gel on arterial blood flow are unknown.
  
  
  OBJECTIVE
  To compare radial artery blood flow, arterial diameter, and perceived discomfort before and after the application of 1 of 4 treatment conditions.
  
  
  METHODS
  Experimental crossover design.
  
  
  METHODS
  Clinical laboratory. PARTICIPANTS OR OTHER PARTICIPANTS: Ten healthy men, 9 healthy women (mean age = 25.68 years, mean height = 1.73 m, mean weight = 76.73 kg).
  
  
  METHODS
  Four treatment conditions were randomly applied for 20 minutes to the right forearm of participants on 4 different days separated by at least 24 hours: (1) 3.5 mL menthol gel, (2) 0.5 kg of crushed ice, (3) 3.5 mL of menthol gel and 0.5 kg of crushed ice, or (4) no treatment (control).
  
  
  METHODS
  Using high-resolution ultrasound, we measured right radial artery diameter (cm) and blood flow (mL/min) every 5 minutes for 20 minutes after the treatment was applied. Discomfort with the treatment was documented using a 1-to-10 intensity scale.
  
  
  RESULTS
  Radial artery blood flow decreased (P < .05) from baseline in the ice (-20% to -24%), menthol (-17% to -24%), and ice and menthol (-36% to -39%) treatments but not in the control (3% to 9%) at 5, 10, and 15 minutes. At 20 minutes after baseline, only the ice (-27%) and combined ice and menthol (-38%) treatments exhibited reductions in blood flow (P < .05). Discomfort was less with menthol than with the ice treatment at 5, 10, and 20 minutes after application (P < .05). Arterial diameter and heart rate did not change.
  
  
  CONCLUSIONS
  The application of 3.5 mL of menthol was similar to the application of 0.5 kg of crushed ice in reducing peripheral blood flood. Combining crushed ice with menthol appeared to have an additive effect on reducing blood flow.
authors.affiliation: Marquette University, Milwaukee, WI 53201-1881, USA. robert.topp@marquette.edu
authors.forename: Robert
authors.initials: R
authors.lastname: Topp
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Ledford
authors.forename: Dean E
authors.initials: DE
authors.lastname: Jacks
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007053:Ice; D008297:Male; D008610:Menthol / Q000008:administration & dosage*; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D017534:Radial Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D014463:Ultrasonography
chemical_list: D007053:Ice; D008610:Menthol