Heat related conditions such as heat exhaustion and heat stroke pose a real threat to the average sea kayaker. Many of us will turn to our kayaks as a vehicle to escape to the sea on the hottest of days. Basking in the sun with a sea breeze to your stern can be a great way to beat the onshore heat but beware. The athletic nature of paddling, the unrelenting sun, and our care-free nature may one day open the door to some form of heat sickness. I’ve been there and it’s none too fun. The good news is that, like most of the common sea kayaking injuries, heat related conditions are fairly easy to manage in most cases and are highly preventable.
The human body is designed such that its chemical processes operate most efficiently at or close to 98.6 degrees Fahrenheit (37 degrees Centigrade). Exposure to heat, vigorous exercise, or a combination of these factors can lead to an increase in body temperature. This is counteracted by the action of the skin which serves as the body’s foremost temperature regulating organ. The skin accomplishes this task mostly via two mechanisms: radiation and evaporation. Radiation is the transfer of heat from the body to the environment via electromagnetic waves. Evaporation consumes heat energy by converting liquid (sweat) into a gas (water vapor). Under normal circumstances these mechanisms do a great job at preventing a rise in core body temperature. However, in extremely hot environments or when humidity rises the evaporative cooling provided by sweat can be adversely impacted. This is when people run into problems with heat-related conditions. As their core temperature rises they are less able to combat against it leading to organ damage and severing metabolic pathways necessary for life.
There are two main types of heat-related conditions that you should be aware of, prepared to treat in the field, and know how to prevent in the first place: heat exhaustion and heat stroke. These conditions describe the clinical presentation of hyperthermia (elevated core body temperature).
Heat Exhaustion is a condition that arises from increased core body temperature but does not result in permanent damage. Signs and symptoms include:
- Mild-moderate core temperature elevation (up to 105F or 40.5C)
- Mild confusion or irrational behavior
- Rapid pulse
- Dizziness or headache
- Nausea or diarrhea
Heat Stroke comes after heat exhaustion and is a life threatening condition in which the core body temperature is so high that irreversible damage may occur. Signs and symptoms include:
- Severe core temperature elevation (above 106 F or 41C)
- Extreme confusion
- Low blood pressure
- Shortness of breathe
- Vomiting or diarrhea
It’s imperative to be able to recognize the signs of heat exhaustion and promptly initiate therapy when it is suspected based on the environment and symptoms. [One should not get caught up in measuring the exact body temperature with a thermometer or making a qualitative judgment call based on how hot the victim feels or if they are sweating. Many victims of heat exhaustion will feel cool to the touch and may be sweating but this does not mean that they are not in danger.] Therapy for heat exhaustion and heat stroke revolves around cooling down the victim’s core body temperature as quickly as possible.
Here are some ways to safely cool a victim:
- Start by removing the victim from the source of heat. Find a place out of the sun and stop exercising as soon as possible.
- Remove as much clothing as possible to expose the skin and allow for a greater area of evaporative cooling.
- Wet the victim down with water and fan them to accelerate evaporation.
- Continue cooling the victim until the symptoms begin to wane.
- Continue to monitor the condition of the victim for 3-4 hours after treatment has been suspended because their core temperature may increase again.
- If the victim is able to drink fluids then try to correct dehydration by having them drink 1-2 liter of water over the period of a few hours.
- If these measures do not provide for noticeable improvement then seek more advanced medical care.
Here are some things to consider or avoid:
- Care should be taken if it is deemed necessary to immerse the victim in cool water to control temperature. In this case do not leave the victims side because a loss of consciousness can result in a near drowning.
- Do not give a hyperthermic victim aspirin or acetaminophen to control their temperature. These drugs will act to control fever in victims with infection but will not do anything positive for victims suffering from hypothermia alone.
- Do not have the victim drink fluids unless they are conscious and capable of swallowing.
The best way to deal with heat related conditions is to prevent them from happening in the first place. The first thing to do is to be aware of the environmental conditions that can lead to heat related illness. The main thing to pay attention to is the Heat Index (or apparent temperature) which provides a measure combining air temperature and relative humidity. When the heat index is in exceeds 90degrees (red on the graph) the normal mechanisms of body temperature control do not work as effectively and one should limit activity until the heat index drops into the safe range (green on the graph).
If you can’t avoid travel on these extreme days then make sure to implement the following strategies to avoid heat-related illness:
- Prevent dehydration by bringing along enough fluids and taking time to drink them on a regular basis. In general, be prepared to drink about 3L of water per day to offset fluid losses by urination and sweating. This amount can vary depending on the intensity of the heat and activity. Consider using a Camel Bak type of hydration system as these allow for more regular intake of fluids throughout the activity without the need for stopping.
- Avoid food and drink with diuretic effects such as: coffee, tea, and alcohol before and during your paddling activity
- Consider bringing along Gatorade or an electrolyte supplement to use if sweating becomes excessive. Otherwise avoid these as your normal diet will meet your salt intake needs.
- Wear lightweight and absorbent clothing in layers. Be prepared to remove or add layers as needed.
- Wear a broad-brimmed hat when in the sun but make sure to remove the hat when you are not in the sun to allow for evaporative cooling from your head
- Avoid drugs that prevent sweating or promote dehydration. Some common drugs in these categories include motion-sickness pills and diuretics.
By implementing these simple strategies you are well on your way to preventing a heat-related illness from sneaking up on you during those hot, summertime paddling adventures!
Happy and Safe Paddling!