Safety

HYPERHYDRATION / HYPONATREAMIA

…….Glen Green, Safety

Hyponatreamia, also called water intoxication, highlights a hazard which can be mitigated through educating endurance events participants on the dangers of hyperhydration.  You don't have to be a marathon racer to experience hyponatreamia, you could be a weekend paddler who spends all day on a whitewater/flatwater trip who drinks too much water without ingesting enough electrolytes.  For medical information on hyponatreamia, see http://tinyurl.com/2co7sc .

From the PHYSICIANSNEWS Digest, July 25, 2012, http://www.PhysiciansNews.com :

1.  Hyperhydration, rather than dehydration, may pose a greater health risk to athletes, according to two articles in a British medical journal.  Heat-induced dehydration rarely causes athletes to collapse during workouts or competition.  In most cases, the culprit is exercise-associated postural hypotension. The primary treatment should be recovery in a head-down position, not fluid intake.

2.  Misperceptions about dehydration have been driven in large part by marketing of sports drinks, according to the authors.  “Over the past 40 years humans have been misled ... to believe that they need to drink to stay 'ahead of thirst' to be optimally hydrated," they wrote.  "In fact, relatively small increases in total body water can be fatal."

3.   A 2% increase in total body water leads to generalized edema that can impair physical and mental performance. Even greater increases in overhydration can cause hyponatremic encephalopathy, leading to confusion, seizures, coma, and -- if not reversed -- death by respiratory arrest.     

4.  Healthy athletes face "barely any risk" of dehydration during competition in an endurance event. Serious health risks -- including inhibition of voluntary motor activity and paralysis -- occur only when total body water decreases by 15% or more, which would require 48 hours in the desert with no water.

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LIGHTNING AND LIGHTNING SAFETY

…….Glen Green, Safety

Lightning is a capricious and random event.  It cannot be predicted with any accuracy.  It cannot be prevented.  Advanced planning is the best defense.  Immediate evasive action could save a life.  25% of strike victims die, and 70% of survivors suffer serious long-term after effects.  Lightning is the 2nd leading cause of weather deaths (behind that of flooding) of all weather phenomena.  Lightning kills approximately 100 people in the U.S. every year.  At any given moment there are approximately 2,000 thunderstorms on the planet earth.  Lightning strikes the surface 100 times per second.  Generally speaking, lightning activity increases with altitude and as you get close to the equator.

If you can see it, flee; if you can hear it, clear it.  If you can hear thunder, lightning is close enough that it could strike your location at any moment.  Go to a safe shelter immediately.  If you wait until you see lightning, it may be already too late to take action. Most people struck by lightning are not in the rain.  14% of lightning casualties occur during water activities.

What causes lightning?  Strong updrafts in thunderclouds carry water droplets upward, supercooling them.  When they collide with ice crystals a slight positive charge is transferred to the ice crystals which cause the upper part of the cloud to become positively charged.  Some of the ice crystals melt with these water droplets which gravity pulls down through the Earth’s natural electric field electrically polarizing them where they accumulate in the lower portion of the cloud.

As a cumulonimbus thundercloud moves over the surface of the Earth, an electric charge equal to but opposite the charge of the base of the thundercloud is induced in the Earth below the cloud.  The induced ground charge follows the movement of the cloud, remaining underneath it.  When a multimillion-volt potential develops, electrons from the cumulonimbus cloud begin zigzagging downward in a forked pattern called a “stepped leader”.  As the negatively charged stepped leader nears the ground, it draws a positively charged streamer (hundred-foot spark) upward from the Earth.  As the leader and streamer come together a powerful electric current begins flowing.  Current begins the return stroke, an intense wave of positive charge traveling upward about 60,000 miles per second following a charge channel about a centimeter (0.4 inch) wide.  This return stroke is the most luminous and noticeable part of the lightning discharge.

The return stroke is an unidirectional (DC) current flow with a voltage potential of 100 to 1,000 million volts, with a current range of 10,000 to 200,000 amperes, that vaporizes its path with 30,000 degree plasma, lasting a duration from 1 microsecond to 1 second.   The main portion of lightning bolt penetrates earth down to the water table.  Spurs find far-reaching paths along the surface.  This is “cloud-to-ground lightning”.  A much rarer “ground-to-cloud lighting” occurs when negatively charge ions in a stepped leader rises up from the ground and meets the positively charge ions in a cumulonimbus cloud.

Being struck by lightning is often preceded by a sensation of all your hair standing on end, along your arms and the back of your neck. If you have this feeling, and you are in (or near) a thunderstorm, the chances are you have sent up a "positive streamer." If this sudden charge connects with the electrons pooling beneath the clouds, lightning will strike. If you feel this sensation, either run as fast as you can for shelter, or drop down on your knees, bend forward and place both hands on the ground.

The air near a lightning strike is heated to 50,000 degrees, which is hotter than the surface of the sun.  The rapid heating and cooling of air near the lightning channel causes a shock wave which results in thunder. 75% of the lightning is “cloud-to-cloud lightning” where there is either discharge between the positively charged upper area of a thundercloud and the negatively charged lower part of the cloud (intra-cloud), or between clouds (inter-cloud).  Also, recently cameras onboard the Space Shuttle have photographed “red sprites” and “blue jets” – huge colorful emissions associated with upward-moving lightning coming from the tops of massive thunderstorms and reaching the ionosphere 50 miles above the Earth.  Lightning can also occur within the ash clouds from volcanic eruptions or can be caused by violent forest fires which generate sufficient dust to create a static charge.  “Heat lightning” is just lightning in the distance where the thunder sound waves dissipate before they reach the observer.  “Thundersnow” is lightning occurring during a Winter snow storm.

The electric field is strongest on ground-connected objects whose tops are closest to the base of the thundercloud, such as trees and tall buildings.  Lightning rods are often attached to the highest points of objects like to the top of the Empire State Building and the Washington Monument, and even to the top of trees in BotanicalGardens.  Lightning rods do not attract lightning, but since there is a higher possibility of a strike on should be mounted.  Lightning Rods work since they provide a lightning strike the shortest and easiest path to ground and they provide the path of least resistance.   Lightning Travels on the surface of the Lightning Rods down a connected heavy gage braided copper cable and down a connected to a connected copper ground rod that has been driven down to the water table.  Recent scientific research has shown that blunt rods are much more effective than pointed.  NASA has recently changed the design of its lightning protection systems at its launch pads from a centrally-located rod to a ring of masts around the perimeter of the complex with catenary cables strung between adjacent masts.

If you are outside, upon the approach of a thunderstorm follow the “30/30 Rule”:  if 30 seconds or less “Flash to Bang” – seek  shelter.  The safest place to go is in a lightning protected building.  The next best choice is going to the interior of a building that does not have lightning.  Getting into a metal bodied car offers some protection.  The rubber tires of a car offer not protection since in a strong electric field, rubber tires actually become more conductive than insulating.  It is the metal enclosure that offers lightning the path of least resistance around you to ground (Convertibles with canvas tops, cars with fiberglass bodies, motorcycles and bicycles offer no lightning protection).  When in a vehicle during a lightning storm, close the windows and keep your hands on your lap.  Wait 30 minutes after hearing the last thunder before leaving shelter, because there are rear striking lightning bolts as the storm pulls away.

5% of lightning occurs without visible clouds in the sky.  Lightning can travel sideways for up to 10 miles, so it is possible for a, “bolt from the blue,” on the edge of a storm.  This is called “Positive Lightning” and unlike the more common negative lightning, the positive charge is carried by the top of the clouds (generallyanvil clouds) rather than the ground. The leader forms in the sky travelling horizontally for several miles before veering down to meet the negatively charged streamer rising from below.  Because of the much greater distance they must travel before discharging, positive lightning strikes typically carry six to ten times the charge and voltage difference of a negative bolt and last around ten times longer.  As a result of their greater power, as well as lack of warning, positive lightning strikes are considerably more dangerous.

If you are in a canoe or kayak on a river, lake, bay, or the ocean, you are usually the tallest object around, and if you hear or see lightning, head immediately for shore and take shelter.  Keep moving.  Don't stop.  The chances of being struck decrease the more you move.  If there are no buildings (do not go to picnic shelters) on shore to take shelter in, then find a low spot under short brush or among a more-or-less uniform stand of smaller trees.  Stay at least six feet away from any tree trunk to minimize a side strike and step voltage.  NEVER take shelter under an isolated tree.  Other options include couching in a low area, ditch, depression, ravine, or foot of a hill.

If once on shore you are trapped out in the open, squat low to the ground on balls of your feet.  Have your heals touch.  Place your hands over your ears, head bowed and mouth open (to help prevent a burst eardrum).  Eyes closed to prevent sight damage.  Hold your breath if you anticipate  an immediate close strike to prevent breathing in superheated air that surrounds a lightning bolt.  Avoid close proximity (minimum 15ft) of other people.  DO NOT LIE FLAT ON THE GROUND – although lying flat on the ground gets you as low as possible, it increases your chance of being hit by a ground current, which is bad.

If you can see that onshore there are apparently no buildings, no brush, no stand of small trees, no low areas to take shelter; or the banks of the river are too muddy, too steep, or too rocky to get out on, then you might be better off to stay in your watercraft in the river and continue paddling until you reach a bridge or even high tension line crossing the river overhead.  You can stay in your boat sitting on your foam filled PFD under the bridge or high tension lines (electrical towers which usually have lightning protection installed) and wait out the storm.   There is no guarantee that lightning will not by bypass striking the bridge or electrical towers, and strike you instead, but at least the odds of some protection are in your favor.

Diving into the water is not a good idea, because if lightning were to strike the water or an object close to the water, the ground current will go through your body while it is dispersing.  There is a “Cone of Protection” Concept (“Protected Zone Concept”) that if you an imaginary cone formed from the tip of a tall isolated object to the ground around that object, the chances are greater that lighting will strike the tall isolated object rather than striking you. 

Some organizations like the National Lightning Safety Institute say that the so-called “cone of protection” from lightning afforded by a nearby tall object is fallacious, and that in reality lightning can easily strike inside the so-called “Cone of Protection”, and even if lightning does strike the tall object, you are still in danger as it dissipates along the ground or side flash.

Although lightning cones of protection have been used for over 100 years, and are currently promoted by some, much confusion still remains as to their effectiveness, particularly as applied to personnel protection. 

Other organizations like the United States Power Squadrons  say that lighting rods on a  tall object like a grounded metal mast on a sail boat or a grounded metal whip on a powerboat protects  areas within its cone :

· 60 degree cone is 99% effective

· 45 degree cone is 99.9% effective

MYTH: Lightning hits the highest point or tallest object.

REALITY: Hundreds of incidents have been recorded involving lightning hitting the trees instead of the tower that dwarfs them, hitting ground mere feet away from telephone poles, and hitting ground in the parking lot of four story buildings

The way the concept of “Cone of Protection” can be applied to a canoe or kayak on a River during a thunderstorm, is that if a river has bluffs higher than you are, or if there is a stand of tall trees or woods growing along the bank, then arguably you have a less of a chance of being struck by lightning if you are in the cone of protection that is formed by the trees on the bank, than if you are in the river outside the cone of protection.  The cone of protection is located about half as far from the trees as the trees are tall (45 degree angle).  It should be repeated that a lighting bolt could still come down and strike even if you are within this cone of protection.

When a tree acts as a natural lightning conductor, due to skin effect, most of the lightning currents flow through the skin of the tree and the sap wood. As a result, the skin gets burnt and may even peel off. The moisture in the skin and the sap wood evaporates instantaneously and may get split.  Stay as far away from the river bank as you can while still being in the cone of protection in order to avoid a split tree from falling on you, and to minimize the chances of any “ground charge” that can spread out at the tree base, travel through the topsoil, through the water and shock you..

Lightning is dangerous and unpredictable.  Experts and standards bodies have not reached consensus on the subject.  You however, have the power to increase your personal safety before and during a thunderstorm by avoiding large bodies of water,  great open fields and areas such as golf courses, small shelters such as bus stops and dugouts, towers, flag poles, light poles, and by avoiding using electrical appliances and equipment, telephones, computers, sinks, tubs, and showers, and anything else that has conductive surfaces and conductive power.  

Technology can help provide an early warning system, there are pager sized lightning detectors currently on the market for under $80 which can be clipped to your lifejacket that sound an audible alarm if there's a strike with a corresponding LED light which illuminates accordingly at lightning distances of 20-40 miles, 12-24 miles, 6-12 miles and within 6 miles.

During an electrical storm, we had best observe Bre'r Fox' advice closely:

"Lay low, an' don't say nuffin."

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PADDLING ON COLD WATER

By Glen Green, P.E., Chairman Safety Committee, United States Canoe Association; Navy Safety Engineer (1991-2006)

The importance of wearing a PFD when paddling on cold water is being brought to National attention by the United States Coast Guard Auxiliary which just issued a “News Release” on February 7, 2011 titled “Life Jackets Saves Lives in Cold Water Too”.

This News Release states that “Swimming ability in warm water has little relationship to the ability to swim in cold water.  Mario Vittone, a former Coast Guard rescue swimmer states ‘It is impossible to die from hypothermia in cold water unless you are wearing an approved flotation device, because without flotation – you won’t live long enough to become hypothermic, you will most assuredly drown’.”

“When the temperature of water is below 50ºF significant physiological responses occur, including the possibility of death,  the causes of death may include cardiac arrest, deep body (core) cooling resulting in unconsciousness, and circulatory collapse, all of which could end in drowning. The effects of cold water immersion are predictable and well documented by what is known as the 1-10-1 Principle:

  1 minute:  Upon immersion in cold water, the body reacts with an involuntary gasp, followed by hyperventilation of up to 10 times regular breathing (if head is underwater during that initial deep gasp, a person can inhale enough water to drown).  Avoid panicking-- breathing will return to close to normal.

 10 minutes:  A person immersed in cold water will become incapacitated as limb muscles stop working and prevent swimming or self-rescue, so swimmer should attempt to rescue themselves, before incapacitation becomes a factor. If this is not possible, try to get as much of the body out of the water as possible to delay the onset of hypothermia.

 1 hour: After about 60 minutes (depending on the water temperature), the body continues to cool. The resulting hypothermia can create a range of symptoms from confusion to unconsciousness, eventually leading to death.”

Post Rescue Collapse(Circum Rescue Collapse):   A victim “gives up the fight”.  In Post Rescue Collapse, which occurs just before, during or after rescue (up to several hours after rescue), the victim has symptoms which can range anywhere from fainting to physical incapacitation to death.  The production of adrenaline ceases once rescue appears eminent.  The feeling of safety stops stress hormones from being produced.  Keep the victim still until medical treatment arrives.

The dangers of hypothermia from capsizing in cold water have long been known by experienced paddlers and racers.  What may not be known by many of us is the “gasp reflex” from cold shock.  No matter how much skill and experience you have, or how fit you are, or how young you are, or if you can swim or not; if you suddenly flip into cold water you will involuntary gasp. 

These physiological responses are described in a paper written by Dr.Chris Brooks, Survival Systems Ltd http://tinyurl.com/4ec32e7:

“Cold shock is caused by rapid skin cooling and can kill within three to five minutes after immersion.  On initial immersion, you make a huge inspiratory gasp. Being immersed in near-freezing cold water is also extremely painful, and the sudden sensation of acute pain can accentuate the inspiratory gasp. The gasp is followed by severe hyperventilation: a fourfold increase in your breathing rate. It is not uncommon for you to be panting at a breathing rate of up to 65 times a minute in this critical stage, so there is no chance to hold your breath. Indeed, in water below 60°F, your breath-holding ability is reduced by 25–50 percent. If the water is near freezing, even after the effects of cold shock have settled, you’ll only be able to hold your breath for about 12–17 seconds.”

 “The rapid breathing rate on its own can cause muscle spasms of the limbs and chest. All of these breathing irregularities increase the risk of drowning if you dip underwater or have a wave splash over your face. It only takes an inhalation of about five ounces (150 ml) of water to cause drowning. Drowning is a combination of cardiac arrest and suffocation. Your heart stops beating within one to two minutes after you have inhaled a significant amount of either fresh- or seawater. Water in the lungs compromises your ability to exchange oxygen, and because respiratory movements may occur for up to five minutes when underwater, water can continue to be drawn into your lungs.”

Some people who are submersed in cold water, instead of gasping, experience a laryngospasm, also known as “dry drowning”http://tinyurl.com/4m2c7ub.Alaryngospasm can occur if the trachea below the vocal cords detects the entry of water, resulting in an uncontrolled / involuntary muscular contraction (spasm) of the laryngeal cords which causes a partial blocking of breathing in.  This is not the same as having one's breath knocked out from force, or swallowing wrong and choking, nor is it related to the shock of falling into cold water and having it "take your breath away".

Whether a person immersed in cold water gasps and inhales water, or experiences a laryngospasm; either outcome prevents effective breathing when the victim surfaces.  Because of this it is important to try to keep your head out of the water if your boat tips over, or get your head above the water immediately before a gasp is uncontrollable.  This is why wearing a PFD is critical, because if you do inhale some water the PFD will bring you to the surface and keep you on the surface as you are gasping or choking.  Being an athlete in great shape has no impact on the body's response to cold water.  Strong swimmers have died before swimming 100 yards in cold water.  In water below 40ºF, such victims have died before swimming 100 feet. 

On March 6th, 1968 nine elite marines, water survival instructors, while paddling a war canoe across the Potomac River capsized in 36ºF water wearing sweat suits, and while they had seat cushions, they had no life jackets. None of them survived the attempted 100 yard swim to shorehttp://tinyurl.com/267ezx

To see a video of a cold-water immersion event, please check out the DVD “Cold Water Boot Camp USA” and “Beyond Cold Water Boot Camp USA, Rescue, Recover, Re-Warm” at http://www.watersafetycongress.org and http://www.coldwaterbootcampusa.org.

If you want a good simulation, turn on the shower and let it run for a couple of minutes.  Run only the cold water and not hot water.  Let the cold water hit your back and the back of your neck and see how long it takes for you to have a spasm.

You may ask yourself, “Well, I have seen members of ‘Polar Bear Clubs’ in the Winter, when the water temperatures are approaching freezing, run down into the water and splash around for a short time without any life-threatening side-effects.”   However, if you observe closely, those that actually dive into the water are gasping when they surface, and usually they are not in water over-their-heads so they are able to stand up to catch their breath; or if the water is over their heads, there are rescuers in very close proximity to help them if they get into trouble.

With practice some people can learn to control the gasp reflex, and some even have the physiology to retain core body heat.  Lynne Cox has swum one mile in 33ºFwater and five miles in 40ºFwater http://tinyurl.com/nuxa.  There are some who have a unique physiology suited to adapting to the cold air and cold water, but these are rare individuals.

When paddling on cold water it is important to stay close to shore unless you can remount your boat immediately (surfski, outrigger canoe), have a bomb proof roll (kayak with a spray skirt), or are able to get on top of your capsized boat.  Cold water robs the body's heat 25 timeshttp://tinyurl.com/67ub5gdto 32 times http://tinyurl.com/2uqsf9 faster than cold air. 

“Life jackets are the seatbelts of the water, always wear a life jacket.” {Cecilia Durer, Executive Director, National Water Safety Congress}.  Consider a USCG approved inflatable PFD if you find that a standard PFD restricts your movements propelling your craft.  Some of these PFDs automatically inflate from hydrostatic pressure of the water (for example: http://tinyurl.com/4erkkgj).

Layers of protective clothing (wool, polypropylene, CoolMax®, etc.), although keep you warm and help wick away sweat while you are training or racing, they are instantly converted to ice-cold dead weight when immersed in cold water.  Such clothing is only useful when worn inside a waterproof shell (jacket, pants, drysuit) having neoprene or latex gaskets at the ankles and wrists.  Dress for the water temperature, not the air temperature.

What is considered “cold water” by an organization is influenced by the probability of being immersed:

USA Swimming 77ºF, USA Triathlon 75ºF, National Water Safety Congress 70ºF, American Canoe Association 70ºF, United States Search and Rescue Task Force 70ºF, United States Rowing Association 50ºF, United States Coast Guard Auxiliary 50ºF, American Whitewater 50ºF.

Many canoe and kayak racers say “It is wrong to impose safety mandates on individuals in a free society, like requiring paddlers to wear a life jacket.”  While it is true that we don’t want regulations that do not contribute to the safety of “athletes in water sports”, but do you want to take a stand and be “dead-right” on your freedom of not having to wear a PFD when paddling on cold water?

While skill and experience may significantly lessen the chance of capsizing in cold water, stuff happens even to the best of paddlers, maybe a missed stroke, maybe the hull of the boat slides up a submerged tree branch, or maybe a paddle strikes a rock while taking a stroke or leaning for a brace, leading to a flip.  Don’t let these upcoming warm spring days ahead lull you into complacency, the best chance for your survival is to wear a life jacket when paddling on cold water.  J

Note: The National Boating Safety Advisory Council is requesting publishers of all materials to use the term “life jackets” because it is felt that many individuals do not understand what a PFD is. [The Boy Scouts of America is also making this change to their “Safety Afloat ©” training.]  The Code of Federal Regulations (U.S. Coast Guard Regulations), however, still uses the term PFD (Personal Flotation Device).

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