Retain Flexibility without Sacrificing Warmth – Fourth Element Xerotherm

We dive cold waters on a regular basis.  When we dive these cold Northwest waters we don’t want to be wrapped up like a mummy to stay warm.  Our dive pals often joke about looking like the “Michelin Man” heading towards the water with undergarment layers. While we might be warm if we wear numerous layers, we can lose fluidity and flexibility, sacrificing ease of movement for warmth.

xerotherm We’ve already told you about the Fourth Element Arctic, our favorite flexible, warm base layer.  With our Arctic, however, and our typical 45 – 46 degree Fahrenheit winter waters, we’ve added and experimented with numerous additional undergarments, including the Hot Chilis, fleece outer jackets and yes, even a cashmere sweater (stylish, yet no one could see it).

Recently, on a challenge by the Fourth Element rep, we got to “test dive” the Fourth Element Xerotherm Thermal Base Layer.  Stylish and sleek, the Xerothem is made using Polartec® Powerstretch®, a material originally developed for NASA.  Xerotherm is touted to trap a layer of air next to the skin, keeping the wearer dry and cozy. The pants have an extra high waist to add a double layer that helps keep the kidneys warm.

On our first test dive, the water temp was 45 degrees Fahrenheit (Note: on the Fourth Element website they recommend wearing a Drybase, Arctic and Ozone layering system at 45 degrees).  I pulled my Arctic undergarment over the top of my Xerotherm base layer.  The fleecy-like lined Arctic slid smoothly over the Xerothem (one of my pet peeves was pulling and tugging the Arctic over the top of Hot Chilis or other fleece leggings).  It was a good first impression.  I squatted, stood up, lifted my knees and turned side to side and found my movement to not be restricted by bulk.  Now to don my super flexible Whites Fusion drysuit and get in the water.

As we descended, I performed my little “Harbor seal test” – if I can turn around to view my dive buddy with relative fluidity I feel like a Harbor seal – and passed the test.  Fluid movement – check.  Torso warm, legs warm, check.  As we continued to descend, several minutes into the dive I found that my upper arms were cold.  Then, some sea critter caught my attention and I forgot about my body temp.  As the dive continued, though, my attention kept wandering back to those cold upper arms.  I made a mental note to add a layer on the next dive as recommended. 

Subsequent dives were in the 45- 46 degree range.  Since we do not like to be a bit cold, I added a cashmere sweater or a Hot Chilis fleece shirt between the Xerotherm and the Arctic.  With these additional layers,  I stayed toasty warm with only a little restricted movement. The last Northwest dive was in 52 – 48 degree water and I stayed comfortably warm with only the Arctic and Xerotherm. (Addendum – with the weather turning warmer outside, I have been wearing only my Artic and Xerotherm lately and am quite toasty.  Sometimes I think that part of staying warm is perception – if I am freezing topside I usually find it difficult to stay warm below, no matter how many layers).

In the middle of our Northwest test diving, we took an excursion to Grand Cayman Island to test dive Fusion drysuits in the tropics (more on this in an article soon to follow). The weather there was uncharacteristically windy, in the 70s.  I donned my Xerotherm every morning at 6:30 before getting on the boat.  With the constant breezes I was never too warm.  Diving in 75 – 79 degree Fahrenheit water, my dive buddy and I were extremely comfortable.  Topside, both of us were comfortably warm, while our wetsuit wearing boat buddies shivered.

Despite the minor setback on my first dive, Fourth Element undergarments continue to be our all time favorite for overall warmth and flexibility.  While we are all different when it comes to staying warm in cold water, some needing more layers, some needing less, we feel that the Xerotherm/Arctic combination is a perfect solution for moderately cold water. The Xerotherm is is also excellent alone under a drysuit in tropical waters. Like the Arctic, even if you get wet in the Xerotherm you stay fairly warm. Supple body movement and flexibility are retained.  While you might have to add an extra layer when the temps drop, you will still find that you retain agile movement and increased range of motion while diving dry and warm.

We found that Xerotherm is also very handy as a base layer for general recreation and especially spring Kayaking. Our minor complaint carried over from the men’s Arctic layer is no pocket. Both men’s and women’s Xerotherm are missing a mini pocket. It is still surprising such an innovative and company did not realize the importance of the key pocket.

Our next Fourth Element test will be on the new bamboo/foam dry glove.