Sweating At The Airport Could Get You Pulled Aside At Security. Here's Why

Clearing airport security in time always feels like a small victory. But any hiccup during the process can make nervous flyers uneasy. While most travellers double-check what items are not allowed, there is one unexpected trigger that may set off alarms - sweat.

In a recent Reddit post that is going viral, user u/ominous_pan shared their experience at a US airport. They were unable to understand why they triggered the scanner at a TSA (Transportation Security Administration) checkpoint - a machine that uses radio waves to generate 3D images of a traveller's body. The user said they had empty pockets and no body piercings. "I flew for the first time in 15 years this week and both airports flagged my crotch at the arms-up scanner," the post read.

It turns out that sweat - particularly in intimate areas - can cause false alarms at airport security, according to Shawna Malvini Redden, an organisational researcher and author of 101 Pat-Downs: An Undercover Look at Airport Security and the TSA, who spoke to USA Today.

"The machine will send up an alarm if there's anything out of the ordinary. Conceivably, the machines could bounce off the sweat and cause a false alarm," Redden said.

Why Airport Scanners React To Sweat

The scanners that require passengers to raise their arms use millimetre wave advanced imaging technology, which operates using non-ionising radiation frequencies, according to the TSA. These waves reflect off the body and can detect water or sweat, as reported by ProPublica. Wearing multiple or heavier layers of clothing can increase sweating and the likelihood of setting off the alarm.

A TSA spokesperson confirmed that "added moisture from a person's body can alter the density of clothing, so it is possible perspiration may cause our advanced imaging technology machines to alarm."

What Happens If Sweat Triggers A Security Alarm

If this occurs, you may have to go through additional screening. While the situation can feel awkward or anxiety-inducing, experts say there is no reason to panic.

"Alarms happen all of the time, and unless you're smuggling something dangerous, the worst that will happen is a manual search in the form of a pat-down," Redden explained. This can be requested in a private room and usually only takes a few extra minutes.