So in answer to the question how does a wetsuit keep you warm, we should start with the basics of how a wetsuit works.Wetsuits keep you warm by catching a thin layer of water between your skin and the neoprene. Your body heats up this water and keeps you warm. It’s important to get a wetsuit that fits properly, otherwise cold water will constantly flush the warm water out. The neoprene in the wetsuit also acts as insulation against environment, so the thicker the neoprene (and wetsuit) the better the insulation will be. The neoprene contains loads of small air bubbles that provide the insulation.
As technology has advanced in the world of wetsuits and neoprene is of such high quality so does the warmth and flexibility. So where-by the basics of how a wetsuit works is important to warmth its not the most important factor anymore. Let's take a look at some of the key features that uses new technology to make the wetsuit warmer.
Glued & Blindstiched
In terms of construction GBS is where in construction of the wetsuit they join the material together by gluing then stitching to form a bond that reduces water penetration. The less water that enters the wetsuit the warmer your body will remain. GBS seams are in all winter wetsuits (5mm Wetsuits) as not having any water enter the wetsuit is crucial in cold water. Where-by some entry level summer wetsuits (3mm Wetsuits) will have a flatlock construction which is where the material is overlapped and double stitched, this form of construction can let some water through the seams but is used in water that is generally warmer so having less impact.
As you can see from the photo the red material is the thermal material which is designed to wick water away from your body and act in the same way as thermal underwear. To the touch the thermal material is soft with slight bobbles. This is generally placed on the chest and kidney area of the wetsuit. The reason for this is to keep the blood flow warm in these key areas thus warm blood is pumped around the body keeping you warmer. Thermal lining is far less flexible than neoprene so does reduce flexibility in the areas to where it is added.
Technology has played a large part in the advent of liquid seams in wetsuits. Liquid seams are designed the minimize even further the possibility of water entering the wetsuit. The process is to GBS the seams first then add this taping to either or both sides of the seam thus making a seal that cant be penetrated. Even as i write this article technology has meant that these seams are reducing in thickness and width to enable increased flexibility. As the more flexible a wetsuit is the better it will feel and the better it will fit, keeping you warmer. So you should consider this when buying a wetsuit. I personally prefer wetsuits without the liquid sealing as i like the flex you get and feeling of not having any restrictions. The seams on wetsuits nowadays is so good that less and less water is getting through the seams.