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When the air temperature gets warm we all head to the lake :)
BUT ... the water is COLD. Without proper equipment
and knowledge your happy and sunny spring day could be your
last :(
PLEASE take precautions so we can enjoy paddleing with you again :) |
What exactly is hypothermia? It is the lowering of the core body temperature
to an unsafe or fatal level. When immersed in water- a highly heat-conductive
medium- our warm bodies automatically begin making efforts to combat heat loss.
Blood from our extremities is routed to our torsos and head in order to keep
major organs and the brain functioning. As time passes, our bodies use up progressively
more of the available energy stores to keep things working. Useful extremities,
like hands, become numb and useless. Shivering, an involuntary reaction of
the body to generate heat, begins in the mid-stages of hypothermia. In the
final stages, our brains begin to shut down, the heart slows, reasoning ability
deteriorates and lethargy sets in, followed by unconsciousness. The human body
can survive in a semi-dormant state of hypothermia for longer than imaginable,
with full resuscitation often possible in a clinical setting; but once unconsciousness sets in, drowning or heart failure may result. It goes without
saying that a PFD increases your survival rate by conserving energy you would
use staying afloat, and providing a fair amount of insulation to your torso.
Gloom and doom, you say? We may well agree, but these incidents happen all the
time in a sport that exposes our warm bodies to the elements and water. Think
immersion won’t happen to you? Ask other people about the first time they went over accidentally,
and most say it occurred when they weren’t paying attention, had no expectation whatsoever of capsizing, or can’t even recall what caused it to happen.
Most people think they can get back in their boat very quickly. Have you ever
actually timed yourself in realistic, cold-water conditions? You are as close
to actually being "in the water" in a kayak as you can possibly be. Realizing this, it is important to recognize
the risks and necessary precautions of keeping you and the water in a reasonable
state of separation when conditions dictate.
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As mentioned previously, the warning signs of hypothermia are distinct in nature, but can be subtle in
terms of onset, depending on the individual. Realize that as your body struggles to stay warm, your brain
is fighting a battle to maintain cognitive reasoning that enables you to remedy your situation. Once
shivering sets in and the extremities are numb, it may become physically impossible to help yourself,
or someone else. Once your brain begins to fail, your reasoning and judgement become clouded, and an
overwhelming sense of fatalism may set in due to brain impairment. Victims of hypothermia often describe
the last few moments before rescue and/or unconsciousness as that of complete apathy towards their situation:
less a feeling of consciously giving up, more one of not understanding what their survival outcome is and no
longer taking any action to help themselves. You cannot help yourself if your brain has ceased to acknowledge
your survival options.
An interesting and well-researched physiological occurrence is known as the "gasp reflex". Some people,
when their head/neck/torso is immersed in cold water, experience an involuntary gasp that can result in
lungs full of water. [I can speak from personal experience here- I’m one of them. In a controlled situation,
I can sort of maintain my breathing. In an uncontrolled situation, forget it!] Something about really cold
water hitting your head triggers a response that is less than helpful when you suddenly are upside down in
your boat. With a buddy close at hand to spot you, check it out for yourself. Hopefully, you might be one
of the people it doesn’t affect!
Conversely, some people can experience an involuntary "mammalian dive reflex." When their heads become
submerged in cold water, their airways involuntarily close to keep the water out of their lungs. This
could be a useful response, except often the airway doesn’t open up again soon enough for one to get a
breath, and a sensation of choking can ensue, followed by hyperventilation after it finally does release.
Again, with a buddy close at hand to spot you, check that one out for yourself, too.
Lastly, there’s a significant response to cold water entering our inner ear during a dunking that can
quickly induce vertigo, the inability of the brain to determine how the body is oriented, while producing
extreme dizziness and nausea. Imagine going over, and then trying to get out of your boat or roll up when
you can’t tell which way is up and where the air you’re craving actually is!
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First and foremost to be cited is knowledge. How can you find out when the water temperature is below or above the safety threshold? Using an inexpensive weather radio (very cheap insurance), you can get information on the water temps in Lake Champlain in hourly updated cycles, 24 hours a day. This info is also available on the local NOAA website. In a pinch, you can call the Burlington Coast Guard station. For other bodies of water, bring a thermometer and immerse it at least 2 feet down to get a reasonable reading, where your body would float.
Let’s say you’ve determined the water is below 65 degrees- what is needed for protection? You need thermal clothing to insulate you from the water and/or the wind blowing over you. There are two basic concepts here: using clothing that completely separates you from the water, keeping you dry and thermally insulated; or clothing that may let you become wet, but is of an insulating material that helps maintain your core body temperature while immersed.
The first option is achieved by the use of a drysuit. This is a waterproof, one-piece suit with latex gaskets at the neck and wrists, and gaskets or attached booties at the feet, which prevents the cold water from contacting your body. Employing a thermal inner layer, which provides insulation - usually fleece and/or polypropylene underwear- conserves your body heat. Your extremities are covered by a wind-proof helmet or hat, gloves, and booties made of an insulating material like neoprene. Drysuits can buy you a lot of time in difficult situations when things just seem to be taking forever. They are the only real option for paddling in water temperatures below 40 degrees F.
The second option is accomplished by the use of a neoprene wetsuit covered by a wind-proof layer for exposed areas. The wetsuit employs a different concept. Upon immersion, a tight, properly-fitted wetsuit allows a small amount of water to come into contact with your skin. The thin layer of water is trapped by the insulating material of the neoprene and warmed by your body, and the close fit of the suit minimizes the further exchange of warm water for cold. Once again, head, hands and feet must be covered as described above. Realize that in all cases, heat loss from the head is the fastest, and you really need your brain to work in these situations, so head coverings are essential. A general rule of thumb is that wetsuits are most effective when the water temp is above 50 degrees F.
Paddlers typically use the "farmer john/jane" suit, a sleeveless suit that still covers the upper torso and chest- very important for preventing the involuntary gasping reflex when you hit cold water. "Shorties" with cut-off legs are also available for those swing days when danger is relatively low. Wetsuits made of lycra with fleece inside make a compromise: they are very comfortable in warm air temps, but do not provide enough insulation in lower water temps. In general, wetsuits are prone to evaporative cooling as the wind blows across their surface, so a windproof layer over your exposed upper body is necessary.
Your personal cold resistance is also a major factor in the equation. There are some paddlers with little "natural" insulation or poor circulation who wear protective clothing on all but the most scorching summer days.
One way you can avoid all the aforementioned is to simply limit your exposure by not paddling during the early or late season. If you want to extend your paddling season, making the investment in the proper clothing is much the same as buying health insurance- it greatly increases your chances of living a long, healthy life instead of ending up a human ice cube! Above all, don’t be lulled into a false sense of complacency when the sun is shining, it’s 75 degrees and you just have to get out there even though the water is still really cold. Wear your PFD, bring another paddler (remember: safety in numbers!), borrow the appropriate clothing- protect yourself!
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Well, now that we’ve determined we as humans are at a significant disadvantage if immersed in cold water, what can we do for ourselves or for others post-event? First, as unpleasant as it sounds, try and find out in advance what your personal tolerance to cold water is. Dress in what you think is adequate clothing and intentionally capsize your kayak with someone standing nearby to watch out for you. Afterwards, note your physical response- at least now you know what you’re dealing with.
If you end up in the drink and manage to successfully cope with the situation, it’s now time to get yourself into dry- or at least wind-proof clothing to encourage your core temp to rise back up. Make sure you always bring a change of dry, warm clothing packed in a drybag no matter what the air and water temperatures are like that day. For someone who is mildly hypothermic, this is usually adequate. For a more severe case, it may be necessary to provide internal heat like a hot drink, or an external source like a fire, sunlight, warmed rocks, body heat from others, etc. to alleviate violent shivering and loss of coordination. An emergency exposure bag, made from heat-reflective material, might be employed here as well. If possible, it is usually a good idea to let the victim rest and regain his wits before continuing on.
It is very important to keep a close eye on the capsize victim for at least an hour after the incident is resolved. Very often there is a loss of ability to judge one’s own fitness after a really cold dunking. The victim may say he is OK one minute, and go into delayed hypothermic shock the next, causing another capsize.
In the most severe cases, where a too-rapid rise in body temperature can result in a heart attack in an extremely hypothermic victim, medical evacuation is imperative, followed by a controlled re-warming of the victim in a clinical setting. In these cases, vigorous rubbing of the extremities can send cooled blood back to the heart too quickly, triggering heart failure, and should be avoided. Above all, don’t give up on the severely hypothermic victim. There have been many documented cases of those who were past the "point of no return" being successfully resuscitated. Get the victim to medical attention as soon as possible, and hope for the best- your efforts may ultimately pay off, so don’t give up hope prematurely.
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