July 14, 2025, 10:37 am | Read time: 3 minutes
Anyone who sweats noticeably at airport security and is then asked to step aside by security personnel must have something to hide—and has been caught. At least, that’s what one might think. After all, excessive sweating is often seen as a possible sign of nervousness. However, it seems that additional screening doesn’t always relate to suspicious behavior.
TRAVELBOOK recently reported on a new development announced by the U.S. Transportation Security Administration (TSA) aimed at “modernizing and improving the travel experience at the country’s airports.” Specifically, it involves eliminating the requirement to remove shoes during security checks. However, passengers subject to additional security screenings are exempt from this relaxation; they may still have to walk through the airport in socks. These individuals might be randomly selected, have the unwelcome SSSS code on their ticket, or simply have worked up a sweat on the way to the airport.
Overview
Sweating Can Cause Problems at the Airport
At least, passengers with sweat-soaked clothing are sometimes asked aside by TSA security personnel. In some cases, this may be because they appear nervous due to their physical condition. Beads of sweat could suggest that someone is up to something. However, it is often simply the moisture on clothing and skin that leads to special treatment.
“The additional moisture on a person’s body can change the density of their clothing,” a TSA spokesperson explained to CNN. As a result, heavy sweating can trigger the so-called Advanced Imaging Technology (AIT) devices, or body scanners, at airport security checks. In such cases, the affected passenger may undergo additional screening–such as a pat-down of the affected body area. This is to ensure that there is no actual threat.
Sweat Could Interfere with Body Scanner Technology
TRAVELBOOK took a closer look at how the so-called full-body scanners, used at airports worldwide, work. According to the Federal Office for Radiation Protection, these modern devices use active millimeter waves to detect non-metallic objects. These high-frequency electromagnetic waves penetrate clothing and are reflected by the skin or objects on the body. The device receives these signals and generates a schematic image, marking suspicious areas anonymously.
Unlike earlier technologies, these scanners do not use health-hazardous X-rays. However, their accuracy heavily depends on how unobstructed the waves can capture the body surface and objects. And this is where the problem apparently lies. Moisture–whether from rain, sweat, or a spilled drink–can disrupt the millimeter waves. It weakens their propagation or causes distortions. The result: The scanner detects irregularities, and the affected person is flagged.
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Tip: Try to Arrive Dry
TRAVELBOOK inquired with airport operator Fraport whether this effect is also known in the operational routine at Frankfurt Airport. The response: No–such a connection is not noticeable in the operational process.
However, this does not rule out the possibility that a passenger appearing drenched at the checkpoint could inadvertently trip up the security system. To avoid delays at security checks, which are certainly undesirable before a flight, it is advisable to keep clothing dry. In rainy weather, it’s best to carry an umbrella and generally allow enough time for the journey to avoid breaking a sweat.