Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.. Stop using Preparation H Cooling Gel and call your doctor at once if you have: This guide also includes a brief look at cooling properties of today’s best-selling mattresses with gel memory foam layers. Cooling pillows are of several types varying on the basis of technology involved and on how does a cooling pillow work, but the type of cooling pillow that stands recommended is Gel Memory Foam pillow, due to the fact that it is among latest innovations and also is accessible at ease. WhiteJack/Shutterstock. Principles of work. While the presence of gel alone isn’t enough to keep a mattress cool, certain applications of the technology can make for a more comfortable sleeping experience.. One feature to pay attention to is how and where the gel is inserted into the mattress. Water filled cooling blankets are essentially pads filled with cool water. Do you want to know how does cooling a gel pillow work? This gel absorbs any excessive body heat, achieving very high cooling rates. Preparation H Cooling Gel rectal side effects. Gel-based cooling blankets, on the other hand, have gel infused into the fabric. Water Or Gel Based Cooling Blankets. Cooling effect. The feeling of coolness arises literally in 20-30 seconds, within a few minutes reaches a maximum, then gradually this feeling stabilizes. Look at our article and learn.