Ink can block sweat glands

Recently, a schoolteacher in France lost his teaching job after parents complained their kids were scared of him. The reason? The 35-year-old man has every inch of his body (even his tongue) covered in tattoos. He’d spent at least 460 hours getting inked.

Tattoo enthusiasts may not be aware that such extreme decorations pose health risks, but they do — from allergic reactions to cancer caused by the black ink and heart disease and heart failure caused by the cadmium in red ink.

Now researchers have identified a new hazard: The ink can keep sweat glands from functioning, leading to chronic skin irritation, heat cramps and heatstroke. A study published in the Journal of Applied Physiology evaluated the amount of perspiration generated by people with tattoos. It turns out that when the body sends a message to sweat glands under inked skin to “Sweat, baby, sweat,” the glands just don’t. In short, “tattooing functionally damages secretion mechanisms,” say the researchers.

So, before getting a tattoo, consider the risks and take precautions.

— Infection? There’s no way to tell if the ink is safe (some, says the Food and Drug Administration, is better suited to painting cars), and bacteria and other pathogenic materials can end up in ink. If the shop doesn’t seem clean or the tattoos are deeply discounted, leave immediately.

— Check that the practitioner is using PPE, and needles and ink from sealed containers.

— Avoid blanketing large areas of the body with ink. Less is more.

— Do research before making your epidermis a canvas.

Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. To live your healthiest, tune into “The Dr. Oz Show” or visit www.sharecare.com.