KANSAS CITY, Mo. — With the Kansas City area under an Excessive Heat Warning this week, experts have stressed there are easy ways to avoid a heat illness.

One of those is as simple as what you choose to wear.

Officials recommend wearing light-colored and loose-fitting clothing if you have to be outside for long periods.

But does it actually help keep you cool?

The National Weather Service in Kansas City put it to the test this week.

The agency put seven shirts of varying colors outside in the afternoon sun Monday. That day the heat index peaked at 119 degrees.

Then using an infrared thermometer, the NWS measured just how hot each shirt was.

A white Chiefs jersey came in last place at 111 degrees and a white cotton shirt was just behind at 119 degrees. Then a neon yellow shirt recorded at 121 degrees.

A gray Chiefs t-shirt showed as 128 degrees, but when the NWS moved over the numbers on the tee, printed in dark gray, it jumped to about 145.

A baby blue polo logged in at 133 degrees, and then the temperatures really cranked up. A black t-shirt and a maroon shirt recorded at a whopping 155 and 156 degrees, respectively.

That’s a 45-degree difference between the hottest and coolest shirt.

The NWS said it’s just science: Darker colored clothing absorbs a lot more heat.

Experts encourage anyone with outdoor plans this week to reschedule or move inside if possible. But if you have to be outside for long periods, make sure you’re prepared. Besides dressing appropriately, drink plenty of water and take frequent breaks in the shade or air conditioning.