Layering for Paddle Sports
Whenever you go paddling it is important to make sure you are properly layering for Paddle Sports. Over the summer with warm water and air temperatures it can be easy to properly prepare for immersion. Winter and Spring days can be a lot harder when sunny days lure unwary paddlers out. Spring can be especially tempting when stir crazy paddlers see air temps climb fairly quickly. Remember, the water temperatures take longer to warm up. Cold water can make any time of year a dangerous time to paddle for anyone who hasn’t properly prepared. Fortunately a little knowledge and the right gear can go a long way in protecting you on the water.
Why Layer for Paddle Sports is Important
So why is layering for Paddle Sports important, and what exactly does that mean? You probably have guessed that you are generally trying to protect yourself from the cold. In Paddle Sports, layering is more specifically for cold water. Most adults have a vague idea of what cold water is but don’t have much experience dealing with cold water. In fact, after a quick online search, not only is there no temperature given for “cold water” but most of the top searches are about cold tap water. The National Center for Cold Water Safety, a great resource for safety information, states that “any water below 70F should be treated with caution.” While the US Army Corps of Engineers (USACE) Water Safety page states “The danger [of cold water] increases as water temperature decreases below normal body temperature (98.6 degrees F).”
This can seem a little extreme when 70 degrees sounds like a perfect temperature for spending time outside! However most people think of 70F air temperature, which is very different since air is less conductive than water. An example of what this means would be to take a wood spoon and a metal spoon from your kitchen. Pick them up and see which one feels colder. They are, in fact, the same temperature. You perceive the metal spoon to be colder because metal conducts heat more efficiently than wood. Water conducts (pulls) heat away from our body more quickly than air, making water feel colder to our skin than air of the same temperature. Because water conducts heat 25 times more efficiently than air, smaller changes in temperature will have a much larger impact.
Stages of Cold Water Immersion
So, what happens in cold water and why is 70F the threshold for cold water? US Masters Swimming Rulebook requires competition pools to be between 77F and 82F for the safety of participants. This is an international standard as it is the requirement for Olympic competition pools as well. Below the threshold of 70F, temperatures start to affect the ability to control breathing. Vessel constriction also starts to occur which leads to increased blood pressure and heart rate. This condition is known as Cold Water Shock and becomes more extreme as the water gets colder. Most people experience the most severe response to cold water shock between 50F and 60F.
After the initial effects of Cold Water Shock, the body moves into the stage of physical incapacitation or swimming failure. The cold water saps energy from the body making movement very difficult. Swimming strokes become less effective, fingers and hands lose dexterity, balance is compromised, all of which make kayak self rescues more challenging. The USACE attributed most cold water fatalities to these first two stages of cold water immersion.
The third stage is the one that most people are aware of: hypothermia. Hypothermia is when you lose heat faster than your body can generate it, leading to a decrease in core temperature. Hypothermia takes time and continues to be a concern even after you exit the water. The final stage of cold water immersion is Circum-rescue Collapse. Circum-rescue Collapse is a sudden loss in arterial blood pressure just before, during, or shortly after rescue from a hypothermic environment.
How do we lose heat?
If you haven’t been permanently traumatized against cold water paddling, the next step is understanding the question “how do we lose heat?” There are four principles of heat loss: Conduction, Convection, Radiation, and Evaporation. Conduction was previously mentioned with the earlier metal and wood spoon example of heat transfer through touch. Convection describes when warmed air or liquid moves away from a heat source and is replaced by cooler air or liquid. Radiation is the transfer of heat emanating from a source, carried by electromagnetic waves rather than the movement or interaction of matter. Radiated heat is like the warmth you feel next to a fire, radiating outward rather than up. Finally, evaporation is the heat loss due to the changing state of water from liquid to gas. Once you know and understand the four principles of heat loss, you can start identifying and using them in every day life.
How do we insulate?
We insulate to slow down the transfer of heat. Most insulation is trapping air to create a barrier and slow this transfer. Loft refers to the thickness of the trapped air space. Wool and polyester are very popular materials used in outdoor clothing because they retain their loft, or airspace, even after getting wet. Cotton, on the other hand, once wet loses all loft. This makes it a very poor choice for activities involving water.
When layering for a day hike or a ski trip, you typically use three layers. Layer one is a wicking layer and is closest to the skin. Its function is to transfer sweat and moisture away from your body keeping your skin dry. The second layer is your insulating layer. It often consists of a nice fluffy wool or fleece meant to create loft and keep you warm. The third layer is the shell layer. The purpose of the shell layer is to create a barrier separating the inner environment from the exterior conditions. Shell layers are usually wind proof and/or waterproof. Oftentimes, clothing combines a few of these layers into one garment. Think about the other outdoor activities you do. Can you identify the layers you use?
Layering for Paddle Suits: Wetsuits vs Drysuits
The purpose of immersion wear is to slow down or eliminate the four stages of cold water immersion, primarily cold water shock, and give you more time before physical incapacitation and hypothermia set in. When layering for Paddle Sports, there are two major categories of immersion wear to choose from: Wetsuits or Drysuits. What is interesting, and hopefully less counter intuitive after reading to this point, is that both wetsuits and drysuits use air to insulate you from the cold.
A wetsuit is made of neoprene, which is a rubber with many microscopic air bubbles. When wearing a wetsuit, it allows a thin layer of water in against your skin. Your body warms up the thin layer of water inside the suit while the neoprene traps that warmer water and insulates it from the colder water outside the suit. Advancements in modern materials reflect radiant heat back toward the body. One example you may have heard of is Columbia’s Omni-heat. Other examples include NRS neoprene products, such as the Farmer John or Farmer Jane, which use a titanium laminate adhesive to reflect body heat. This is a really cool advancement because, for a long time, radiant heat was thought to be an inevitable and unavoidable loss.
A drysuit is made of waterproof fabric with waterproof zippers and latex gaskets that seal around the neck, wrist, and sometimes ankles, to prevent water from penetrating the suit. Essentially, a dry suit is a shell layer providing a barrier from the outside environment. You still need to layer underneath a drysuit to insulate from the cold water, but since you stay dry, your body doesn’t work as hard to warm the air inside the suit. Because of this, drysuits are more popular as water and air temperatures get lower.
While maybe not directly translatable to kayaking because of cuts, a very interesting table for wetsuit thickness guidelines can be found on Scubadiving.com that recommends drysuits for diving in waters below 50F. The Columbia River and Willamette River get down to 40F or colder in Winter! Some of the glacially fed whitewater rivers rarely, if ever, get above 50F even in late summer. For this reason, when paddling the shoulder seasons (spring and fall), a neoprene wetsuit is recommended. A drysuit remains the best option for year round paddling.
When layering for Paddle Sports, no matter what you choose to protect yourself from cold water, there are a few great pieces of advice to remember:
- Always dress for immersion. We are always between swims and accidents can happen. Don’t get caught unprepared because you thought the improbable was impossible.
- It is always easier to cool off than to warm back up. Remember, cold water surrounds you. Splashing some water on your face, head, and neck are great ways to cool off. If that isn’t enough, you can always practice a rescue with a friend.
- Test your gear in the conditions you plan to use them. Just because John Doe tells stories of paddling in blizzards back in the day doesn’t mean he still does or that you should. Nothing is worse than thinking your gear will be adequate only to find out half way through a trip that it isn’t.
Sources and articles of interest:
Whats a safe Pool Temperature? usms.org
US Army Corps of Engineers Water Safety
Scuba Wetsuit Thickness Guide Scubadiving.com