Thinking of getting a tattoo? An interesting recent study suggests, that came to my attention at the American College of Sports Medicine meeting in Denver, suggested that athletes may need to think twice before getting a tattoo... Tattoos have increased in popularity in recent times and it seems that especially in sport tattoos are prevalent. One anecdotal report indicated that 53% of all NBA basketball players during the 2015 to 2016 season were tattooed and that for two NBA teams, the Cleveland Cavaliers and the Houston Rockets, these numbers were as high as 3 out of every 4 players.
The tattooing process involves puncturing the skin with needles that contain a dye that is released and deposited 3-5 mm below the skin surface into the dermal layer. This dermal layer also contains sweat glands which are responsible for secreting fluids and play an important role in thermoregulation. It is therefore reasonable to question whether the tattoos interfere with a normal sweat response. A recent study investigated exactly this question (1).
The investigators recruited 10 individuals with tattoos on one side of their body. They measured sweat rate and sweat composition (sodium) in an area that was tattooed and they did the same on the other side of the body without a tattoo. The results clearly showed a lower sweat rate (53% lower) and a higher sweat sodium concentration (64%) from tattooed versus non-tattooed skin. This suggests that not only sweat rate is compromised but also that sodium re-absorption is impaired. So it appears that tattoos interfere with a normal sweating response. The authors also commented that these effects were not related to the age of the tattoo.
So what is the practical relevance? Should athletes avoid tattoos to maintain their ability to thermoregulate? It is probably too early to draw that conclusion and the answer is very likely: "it depends". It is likely to depend on how much skin has been covered with tattoos. For now, it is probably good for everyone, who is thinking of getting tattoos that will cover large parts of the body, to realise that this may have an impact on thermoregulation and potentially performance, especially in hot conditions.
References
1. Luetkemeier et al Med Sci Sports Exerc 49(7): 1432-1436, 2017.