The popularity of tattoos has increased tremendously in the last 10-years particularly among athletes and military personnel. The tattooing process involves permanently depositing ink under the skin at a similar depth as eccrine sweat glands (3-5 mm).
PURPOSE: The purpose of this study was to compare the sweat rate and sweat Na+ concentration of tattooed vs. non-tattooed skin.
METHODS: The participants were 10 healthy males (age = 21 +/- 1 yr) all with a unilateral tattoo covering a circular area at least 5.2-cm2. Sweat was stimulated by iontophoresis using agar gel disks impregnated with 0.5% pilocarpine nitrate. The non-tattooed skin was located contralateral to the position of the tattooed skin. The disks used to collect sweat were composed of Tygon(R) tubing wound into a spiral so that the sweat was pulled into the tubing by capillary action. The sweat rate was determined by weighing the disk before and after sweat collection. The sweat Na+ concentration was determined by flame photometry.
RESULTS: The mean sweat rate from tattooed skin was significantly less than non-tattooed skin (0.18 +/- 0.15 vs. 0.35 +/- 0.25 mg/cm2/min.; p=0.001). All 10 participants generated less sweat from tattooed skin than non-tattooed skin and the effect was -0.79. The mean sweat Na+ concentration from tattooed skin was significantly higher than non-tattooed skin (69.1 +/- 28.9 vs. 42.6 +/- 15.2 mMol/L; p=0.02). Nine of ten participants had higher sweat Na+ concentration from tattooed skin than non-tattooed skin and the effect size was 1.01.
CONCLUSION: Tattooed skin generated less sweat and a higher Na+ concentration than non-tattooed skin when stimulated by pilocarpine iontophoresis.
(C) 2017 American College of Sports Medicine