Even suggesting a tattoo can negatively impact endurance performance sounds like heresy. Tattoos have become part of our life (or more accurately our bodies). Approximately 30% of Americans have at least one tattoo, which is a significant increase over the last seven years. Against this backdrop is a recent report that suggests tattoos could impact endurance performance. First some explanation. During extended endurance activity, it is essential that the body’s cooling mechanisms work efficiently. Small increases in core body temperature can increase fatigue and reduce endurance. Your body's sweat glands are responsible for maintaining body temperature. During exercise, heat generated by your muscles is delivered to the surface of your skin where it forms sweat and as the sweat evaporates it cools your body. It’s logical to assume that any interference with the functioning of your sweat glands, would decrease cooling and thereby reduce endurance.
In this study, researchers studied the impact of tattoos on the sweat mechanism. Using a perfusion suit, hot water was circulated on the skin for 30 minutes and researchers measured skin temperature and sweating on the tattoo and in the skin area adjacent to the tattoo. Although both the tattoo and non-tattooed area began to sweat at the same time, there was a reduction in sweat produced by the tattooed skin. By inference, any reduction in sweat production could impact endurance performance. The researchers concluded that tattooing may damage sweat glands.
From a practical sense is this realistic? The surface area of the average person is 2600 sq. inches. Even a 10 inch by 10 inch tattoo would only affect about 4% of your skin surface area. I doubt whether that will impact your endurance performance. However, if you are looking for a reason why your last workout was terrible you can blame it on your latest tat.