The reality of Hot Weather Kayaking is…if you DON’T regulate your body’s heat gain YOU WILL suffer a heat injury of exhaustion or even stroke. Now let’s look at what that really means if you are kayaking or hiking in the heat. And let’s see how you can prevent it.
This article is not written to present startling information about hot weather. It is written to remind kayakers and all outdoors people that hot weather requires extra consideration. Nor is this article written from a medical standpoint. This article is written for the benefit of the outdoor person, especially the kayaker.
As a kayaker, you are the master and commander of your own boat, making the decisions for your own welfare.
With good decisions, heat-related illnesses 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.
Firstly, you must know your abilities. This is easier said than done because once you begin to suffer from over-heating, your brain’s ability to make rational decisions diminishes quickly.
You must be honest with yourself in terms of your physical preparation. Don’t go out for a paddle after a heavy night drinking if it is forecast to be a hot day. You must prepare for your intended kayak trip with the right gear.
Most of all, you must know the signs of an impending heat injury and then take action.
Considerations of Kayaking in the heat – paddling in a hot air and warm water environment.
Hong Kong air temperatures in summer sit between 30 and 35 degrees C in the shade. On the ocean there are no trees! NO SHADE! The ‘in the sun’ temperature will easily be 45 to 55 degrees C. This is really hot.
Hong Kong sea water temperatures sit between 27 to 32 degrees C. This is very warm water.
Heat Facts… to be concerned with while kayaking. Your body will gain heat in the summer on the water while paddling by (a) direct solar exposure, (b) the reflected light off the water, (c) any lack of wind to carry away heat by convection and (d) conduction from anything that you touch that is hotter than you (your black kayak seat, your red PFD, your black carbon fiber paddle shaft, a dark hat on your head, etc.).
Hot air concerns:
(a) If the air is hotter than your body you will NOT lose heat by radiation to the air.
(b) If the air is not moving you will not lose heat by convection.
Guidelines for Preventing Heat Exhaustion while Kayaking:
1) Paddling during the day…stay wet. Get out of your kayak and take a dip occasionally. Water will conduct heat away fast. And by being wet you create a powerful evaporative process that will keep you cool. We regularly stop paddling to find a shady place on shore or go for a swim, or do a wet exit practice.
2) Drink water to ensure that you do not become dehydrated. If you are dehydrated then you cannot sweat properly. Sweating is the body’s #1 process to keep cool. It is a process of losing water. But it is a process of evaporation which is the process of cooling. Include in the process of drinking water an electrolyte replacement such as Pocari Sweat.
3) Dress in loose fitting clothes that have vents. Loose fitting clothes allow air movement, air movement allows heat loss by convection. Venting allows the air that has gained heat to vent away from your body. Always wear a hat and sunglasses. A scarf too if you do not have a wide-brimmed hat that covers your neck.
4) Dress in light colored clothes. Light colored clothes reflect the sun’s light, therefore less light is transformed into heat on the clothes you wear.
5) Cover yourself completely. Direct heat gain on your body is direct heat gain on your body.
All heat gain sources on a hot summer day in Hong Kong are significant – but the methods of preventing a heat injury are deceptively simple in fact its just maths.Lose more heat than you gain.
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 vapour). 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 concrete 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 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. In hot weather, while sea kayaking wear protective clothing that is light coloured.
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 can 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 not too much. Importantly, you should not consume large quantities of alcohol the night before you are going to paddling if it is forecast to be hot.
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. Keep it on your deck within easy reach. Most athletes during strenuous activity need about 0.5 to 1 litre per hour. This of course, will vary with the individual and with the heat and humidity. But, more than a litre per hour every hour for an extended period could lead you to OVER-HYDRATION, which is just as dangerous. Replace electrolytes.
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 mls every few minutes AND NOT all your water 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.
Acclimatisation: 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.
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
7) headache8) nausea or vomiting
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 down in the water’s edge with your head closest to the beach, 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.
You will lose to the heat every time that you underestimate it.