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Scuba Diving Heat Loss Management

During lengthy immersions, recreational divers lose body warmth underwater due to two heat transfer mechanisms - conduction and convection.

This section explains how heat loss occurs in scuba diving and how to handle mild and severe cases of immersion-related hypothermia during and after a dive.

What is Hypothermia in Scuba Diving Terms

The key factors that affect loss of body heat in cold environments are:

Pro Tip: The simple definition of scuba diving hypothermia is when the core temperature of the body drops below 35° Celsius (95° Fahrenheit).

Dangers of Heat Loss in Diving

The main reason why immersion in cold water leads to hypothermia is because water conducts heat away from the body more than twenty (20) times faster than air.

Without adequate thermal protection, an abrupt dive into water colder than 15° Celsius can trigger the Cold Shock Response. The effect can also cause salt water aspiration syndrome for divers, snorkelers, and swimmers.

Furthermore, the heart beats faster and there will be an increase in the breathing rate. The sudden cold shock may also lead to pain (e.g. headache), mental disorientation, and panic.

Tips for Preventing Scuba Diving Hypothermia?

Are you a diver that gets super cold while scuba diving or snorkeling? If the answer is yes, there are several things you can do to prevent hypothermia - or at least reduce the severity.

Wear the Right Exposure Suit

First, always wear an exposure suit that is adequate and heat loss efficient. It's fair to say some of the best places to scuba dive have warm water.

Even so, wearing a thin wetsuit (e.g. 3mm shorty wetsuit), or a hooded vest, will provide some protection against rapid heat loss and hazardous marine life.

Of course, you will need to wear a much thicker wetsuit (or even dry suit with undergarments) if you dive in very cold water or you enjoy making deep dives. If so, remember to wear dive gloves, a hood (or a scuba beanie), and dive shoes (boots)

Have a Windproof Jacket

One of the common mistakes beginners make is not having any appropriate clothing to wear after the diving has finished. Almost always, exiting the water is going to expose your body to the chill of the wind, and in some cases, cold rain.

So, it is best to remove your wetsuit as soon as you get out of the water and put on a warm and windproof jacket and a woollen hat. Remember, wearing a damp wetsuit is going to contribute to evaporation - and lead to further heat loss.

Recognise the Signs of Hypothermia

There are some common factors that make divers more vulnerable to heat loss and hypothermia. Typical examples include:

Pro Tip: As a scuba diver, you should know what to do if you get cold while diving and you can't stop shivering, or you see your dive buddy shivering. End the dive in a safe manner (without delay) get out of the water, dry off, and put on some warm clothing.

Mild Hypothermia Symptoms

Mild Hypothermia Treatments

Symptoms of Severe Hypothermia

Severe Hypothermia Treatments

If Responsive

If Unresponsive

Extreme Cold: Special Considerations

In some situations active rewarming may be appropriate, such as if the victim is no longer shivering and medical aid is delayed.

Following the recommended care guidelines, apply wrapped heat packs or warm hot water bottles to the armpits, groin, trunk, and side of the neck. The source of heat should be warm or tepid, but not too hot.

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