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Heat Illness and scuba Diving

The typical signs and symptoms of temperature related injuries in scuba diving vary according to the cause or the severity of the condition.

This guide explains how to recognise heat exhaustion and heat stroke, and how to manage divers with heat illness or severe hyperthermia (elevated body temperature).

First Aid for Divers with Minor Heat Injuries

Skin Blisters and Hot Spots

Wearing the wrong size scuba equipment is likely to cause blisters and red hot spots.

But, keep a skin blister clean and it should heal in a few days - without causing you too much pain.

In most cases, it's best not to break open the soft skin and try to keep any loose flaps intact to form a barrier.

Moleskin tape (or a thick bandage) can help to protect sensitive areas from further friction. If not, you can also use a compound tincture of benzoin to glue the blister to the underlying skin, such as in areas that are difficult to bandage.

Note: Always use a sterile needle, or sharp blade, to make a tiny incision if you need to drain the swelling. Keep the wound clean and dry after cutting the bottom edge of the pustule.

Infected Open Wounds

The main concern with an open wound is that it may become infected. Contributing factors to wound infections are stress, sweat, diet, an increased physical activity, and dirt.

For that reason, the best way to manage a wound, and to identify whether it needs medical attention, is to use the acronym SHARP, which stands for:

Swelling
Heat
Aches and pains
Redness
Pus

What if you see signs of infection appearing at the wound site? If so, clean it again using moist heat (as hot as the patient will tolerate). Repeat this process every four (4) hours and change the dressings several times per day.

Thermoregulation Failure (Hyperthermia)

Overheating is a concern for people who dive or snorkel at the hot diving destinations around the world. Thus, the combination of insufficient hydration and a hot sun environment can lead to heat exhaustion.

If a diver is heat exhausted, they will have a headache, sweat profusely, feel dizzy, and they may also be vomiting (not common).

Despite being an uncomfortable condition, quick hydration and resting somewhere cool and shady usually provides rapid relief from the symptoms.

Here's the concern...

If heat exhaustion is not controlled, it can worsen into a condition known as "heat stroke". You should consider this as being a warning sign of a medical emergency that requires immediate medical intervention.

Heat Exhaustion Symptoms

Overexposure to a hot sun and high temperatures is a major cause of heat injuries in scuba diving. Plus, wearing a thick neoprene wetsuit for long periods on a boat or dry land can make the situation more serious.

If you can cool down a diver with heat exhaustion within thirty (30) minutes, the need for emergency medical help usually decreases.

The typical signs and symptoms of a diver with early stages of heat illness include:

Weak rapid pulse
Dizziness
Rapid, shallow breathing
Profuse, excessive sweating
Headache
Heat rash (prickly heat)
High temperature
Nausea, diarrhoea, and vomiting
Muscle cramps and spasms (e.g. arms, legs)
Headache, thirst, and dizziness
Flushed, clammy pale skin
Tiredness and asthenia (general weakness)

Pro Tip: Even though the symptoms of heat exhaustion are almost the same in all age groups, children are likely to become irritable as well.

Heat Exhaustion Treatment

Lay the diver down and protect them from the environment in a place that is cool and shaded.
Remove as much of the diver's excess clothing as possible, especially the exposure suit.
Provide sips of cool water, or a sports rehydration drink (e.g. containing sodium and potassium).
Cool the diver's skin using a moist cloth or water spray. Beside fanning their body, you can also wrap cold packs inside a cloth and place them under their armpits or on the neck.

Important: Do not leave the patient alone until their body cools down and they start to feel better. Seek medical advice and sunstroke treatment if this does not happen within thirty minutes.

Heat Stroke Symptoms

If scuba divers or swimmers have prolonged exposure to high sun temperatures, especially combined with physical exertion, it can result in a serious condition called heat stroke - a fatal form of heat injury.

Hence, a core body temperature of 40° Celsius (104 Fahrenheit) or higher is likely to show these classic symptoms of sunstroke:

High body temperature (e.g. higher than 40° Celsius)
Rapid shallow breathing
Sweating stops (there will be little or no sweating whatsoever)
Hot, red, dry, or damp skin
Rapid, strong pulse (which may become slow as the condition worsens)
Convulsions
Altered responsiveness, sometimes becoming unresponsive
Dizziness
Headache (often accompanied by confusion)
Nausea
Passing out (leading to a loss of consciousness and death)

Heat Stroke Treatment

Seek urgent medical assistance and lay the diver down in a protected area away from the hot environment.
Monitor the patient's consciousness, airway, breathing, and begin CPR if necessary.
Sponge them with cold water or wrap them in cool wet sheets (or large wet towels). Fanning will also assist the heat transfer mechanism.
Provide them with sips of cool water if fully conscious and able to swallow. You may also begin administering supplemental oxygen if available and you have been trained to do so.

Pro Tip: After trying to cool the body down, seek medical attention without delay if a scuba diver stops sweating, begins to suffer heat cramps, or faints.