Not regulating human body heat gain is what leads to heat injuries.
Hot Weather Kayaking and Adventure by Robert Finlay of Kayak Lake Mead
This article is written to provide important information for adventurers planning strenuous activities
such as kayaking or adventure racing in hot weather.
I have a lot of experience in hot environments (resume) both humid and dry and we professionally guide hiking adventures in the desert. The content of this article seems "too simple" and too obvious for me to even write an article. But then again, I learned the symptoms, the effects, and the treatments for dehydration, heat exhaustion, and heat stroke the hard way, by making mistakes and suffering the
consequences and I was sometimes lucky to have survived.
Sidebar: One example of hot weather physical activity experience... As an ironworker, building a bridge near Palm Springs during July... Working on the footings for the piers...In the hole with cut earth embankments on both sides... Placing the steel reinforcing rods... Inside steel oily forms... With the ambient air temperatures around 125 degrees F and generally little or no wind... The temperatures that I and my crew dealt with for the entire month were over 145 degrees F. Crazy, huh?
Every year I see visitors to the desert, hikers and kayakers succumb to the heat. Simply because they are not conditioned to the heat and or they are not educated about strenuous physical exercise in the heat.
This article is not written to present startling information about hot weather. It is written to remind kayakers and all adventurers, myself included, that hot weather requires extra consideration. Nor is this article written from a medical standpoint. For instance, there are a host of illnesses and medical conditions which lead to dehydration. This article is written for the benefit of the outdoor athlete, especially the kayaker.
As a kayaker, you are the master and commander of your boat, making the decisions for your welfare. With good decisions, heat injuries are very easily avoided. You must know your abilities. You must be honest with yourself in terms of your physical preparation. You must prepare for your intended kayak trip with the right gear. You must know the signs of an impending heat injury and then take action.
The Concepts of Human Body Heat Gain:
The body's normal operating temperature is 98.6 degrees F. Temperatures above that are abnormal and NOT healthy.
The body loses heat from the processes of heat transfer; radiation (object to a medium), conduction (object to object), convection (moving medium next to object), and evaporation (conversion of water to water vapor). Those are the basics for understanding hypothermia, the process of the body losing heat faster than it is retaining or producing heat.
Understand those same processes of heat transfer and you will better understand hy-PER-thermia, the process of the body GAINING heat.
Radiation - You are immediately aware of radiation when you walk across a black top parking lot on a hot summer day. The parking lot is radiating because it is hotter than the air. Now, your body radiates heat to stay cool. But if the ambient air temperature is greater than your body's temperature, YOU won't radiate any heat away.
Conduction - Sit down on that black top parking lot and you immediately become aware of conduction. Conduction occurs from hotter objects to cooler objects. When you walk across the parking lot heat will be conducted into your feet.
Convection - About halfway across that parking lot, when the breeze comes up, and you feel a relief of coolness, you're thankful for convection. Moving air transports heat away from your body.
Evaporation - Parking lot or not you sweat to cool off. Let yourself get dehydrated and you won't have the fluid to sweat. Sweating is your body's PRIMARY method of cooling off.
Direct Solar Gain - When light energy strikes the surface of a solid object the energy is converted to heat. This is called heat absorption. Heat absorption from the sun is nature's PRIMARY method of making you hot. Dark surfaces absorb more heat than light objects.
Dehydration: Causes, Symptoms, Effects, Treatment
I am not going to define dehydration, OK?
Causes: Not drinking water and drinking diuretics instead of water (coffee or other drinks with caffeine). Kayakers often find themselves dehydrated because they are paddling, paddling, paddling and their water bottle is...somewhere. To use their bottle they have to stop paddling to drink and often when they do stop to drink they don't drink enough.
A little coffee is fine before paddling, but you probably don't need to do what I do and take a thermos
of coffee with you while paddling in the summer.
Symptoms: These are the signs of dehydration. If you are paddling alone just pay attention to yourself. If you a kayaking with others, give a little attention to your mates. Make sure they and you are drinking water, sweating, peeing, and getting enough rest.
If you or your friends are light headed, dizzy, or confused you have gone too far without caring for yourselves.
2) less-frequent urination
3) dry skin
5) light headedness
8) dry mouth and mucous membranes
9) increased heart rate and breathing
Effects: Basically if you have let yourself become dehydrated you will not have the fluids in your body
to produce sweat, the body's wonderful evaporation process. So, you won't cool off and can likely
spiral down into the next level of heat injury, heat exhaustion.
Treatment: Have water in your bladder/bottle, and drink it occasionally. Most athletes during
strenuous activity need about 16oz to 28oz per hour. This of coarse will vary with the individual and
with the heat and humidity. But, more than a quart per hour every hour for an extended period could
lead you to OVER-HYDRATION, which is just as dangerous. Replace electrolytes.
When paddling, I usually place my 100oz water bladder in my cockpit between my legs. The tube
comes up to a small bungee that is on my PFD below my chin...I'm staying hydrated.
Heat Exhaustion: Causes, Symptoms, Effects, Treatment
Definition and Causes: Heat exhaustion is a milder heat-related injury that WILL develop after
exposure to high temperatures and inadequate replacement of fluids. Unbalanced replacement of fluids
can also lead to heat exhaustion. You have got to sip your water incrementally. Drink a few ounces
every few minutes AND NOT all 28 ounces at the end of the hour. This is another reason kayakers
suffer from dehydration. Stopping on rare occasions to sip only a little water is not going to cut it.
Heat exhaustion can also occur even when you are hydrated. Any combination of high ambient air
temperature, a hot radiating environment, contact with hot surfaces, no air flow, super solar heat gain,
with or without hydrating can cause you an abnormal heat gain.
When you exercise you gain heat literally by burning fuel. The harder you exercise, the hotter you will get.
Acclimatization: Practice being hot. That's right, if you are in an air conditioned office day after day,
you will NOT be prepared for a hot weather kayaking trip. Get out a few days a week for a few hours
and exercise vigorously outside in the heat. The best short, vigorous, outdoor aerobic fitness workout
I know is stair or hill work. Combine that with a kettlebell workout, for instance, and you WILL
prepare for that hot weather kayak trip.
Fitness: Good aerobic fitness is one of the best ways to protect yourself from heat injuries. The fit
kayaker has a well developed circulatory capacity (moving more blood) and an increased blood
volume (more fluids to dissipate the heat).
Symptoms: If you have let yourself or your friends get to the point of these symptoms, you are
starting to get in trouble.
1) heavy sweating
3) muscle cramps
4) tiredness / fatigue / exhaustion
8) nausea or vomiting
Heat Exhaustion Treatment and First Aid:
1) Reduce your personal heat production by reducing the intensity of your activity.
2) Get out of the sun, get in the shade, or under substantial cover.
3) Remove clothing and gently apply cool water to the skin followed by fanning to stimulate sweating.
4) Apply ice packs or chemical cold packs to the groin and armpits.
5 Lie down in a cool area with your feet slightly elevated.
7) Hydrate if needed and recharge your electrolytes.
8) Note to kayakers: Beach up, lay in the water's edge, WITH a sun cover over you.
Heat Stroke: Causes, Symptoms, Effects, Treatment
Heat stroke is heat exhaustion taken to a dangerous level, a life threatening emergency.
It is the result of long, extreme exposure to the sun or from long extreme strenuous activity even in a
hot cloudy/overcast environment.
It is the result of YOU not regulating your heat gain.
It is characterized by all the symptoms of heat exhaustion PLUS...
2) disorientation, agitation or confusion
3) extreme sluggishness or fatigue
4) hot, dry skin that is flushed but not sweaty
The treatment and first aid is the same as we have already discussed PLUS GET MEDICAL HELP.
Over Hydration / Excess Hydration Description and Dangers:
1) Excess water consumption causes dilution of your sodium and electrolyte levels.
2) You will feel bloated.
3) You will be peeing a lot.
4) It can lead to death.
Note: If you are exercising hard in the heat and are drinking more water to stay hydrated in your
concern NOT to be a heat casualty...THEN you must also increase your electrolyte intake.
Optimal performance as an athlete / kayaker requires that you be neither dehydrated or over hydrated.