USA: Tattooing and Its Impact on Sweat Secretion

A recent study in the Journal of Applied Physiology suggests that tattooing may impede sweat secretion, impacting heat dissipation and potentially resulting in overheating of the body.

Skin tattooing involves repeated insertions of a needle to deposit ink into the skin's dermal layer. This process could have a damaging effect on the eccrine sweat glands and the cutaneous vasculature. The study, conducted by Scott L. Davis from Southern Methodist University, United States, and colleagues, tested the hypothesis that reflex increase in sweat rate (SR) and cutaneous vasodilation is blunted in tattooed skin (TAT) compared to adjacent healthy skin (CON) during passive whole-body heat stress (WBH).

The study included 10 people (5 men, 5 women) with a sufficient area of tattooed skin. SR, skin blood flow (laser-Doppler flux; LDF), skin temperature (T_skin), and intestinal temperature (T_int) were continuously measured during normothermic baseline (34 °C water perfusing a tube-lined suit) and WBH (increased T_int 1.0 °C via 48 °C water perfusing suit).

Key Findings of the Study

• SR throughout WBH was lower for TAT compared to CON.
• Accumulated sweating responses during WBH (area under curve) were attenuated in TAT relative to CON (23.1±12.9, 26.9±14.5 mg×cm^-2).
• Sweating threshold, expressed as the onset of sweating in time or T_int from the initiation of WBH, were not different between TAT and CON.
• Tattooing impeded the ability to obtain LDF measurements.

"Our data suggest that tattooing damages natural secretion mechanisms and affects the reflex capacity of the gland for sweat production. However, tattooing does not affect neural signaling to initiate sweating. Decreased sweating in turn impacts heat dissipation especially when tattooing covers a higher percentage of body surface area. This could be considered a potential long-term clinical side effect of tattooing," concluded the authors.

The study, "Skin tattooing impairs sweating during passive whole-body heating," is published in the Journal of Applied Physiology.

DOI: https://journals.physiology.org/doi/abs/10.1152/japplphysiol.00427.2019