Think Hypothermia Is Only a Cold Water Risk? Think Again.


The air temp is 90° and the water a balmy 80° – so you forgo your wetsuit or just wear a lightweight skin. After all, it’s hot in the tropics and you can’t wait to cool off underwater.

Ahhhh….it feels so good to descend away from the scorching sun and hot, humid air into the cool, tropical sea. You’re cruising around, exploring the reef. It’s a fairly shallow drift dive, so you barely have to exert any energy swimming and know you’ll get to stay under for quite a while.

Then you start to feel a little chilly, no biggie, right? You still have at least 25 minutes of air, so you shrug it off.

A few moments later, your body starts shivering and you’re suddenly feeling kind of tired, and your arms and legs are having trouble navigating through the water. By the time you reach the surface, you’re freezing, disoriented, and your body is seemingly out of your control.

What’s the prognosis? Hypothermia.

It seems absurd on the surface, doesn’t it? Diving destinations are, for the most part, exceptionally warm with blaring sunshine and a tropical climate, so how can hypothermia even be possible in these beach vacation conditions?

Core Body Temperature

It all relates to your core body temperature.

Hypothermia can occur when your core body temperature drops below normal, which is 98.6 degrees, and your body’s internal heating mechanisms can’t compensate for the heat loss. Making up for this loss is an easy feat for all humans on land, but water draws away heat from a body roughly 25 times faster than air, so once submerged on a long dive, your body is losing heat much faster than it can be produced. The end result is mild hypothermia, and it’s been reported in waters as warm as 90 degrees.

It’s surprisingly common, and often overlooked as other concerns, (like decompression sickness), tend to garner more attention. But most problematic is that is can be difficult to identify.

Why is Hypothermia Sometimes Difficult to Identify?

Unlike traditional hypothermia, which has a fairly obvious onset, warm water hypothermia is often referred to as the “silent hypothermia” because it can be tricky to pinpoint as it occurs. The core temperature drops so slowly in these conditions that a diver might still feel perfectly warm while the body’s heating mechanisms are struggling to keep up. Even shivering – an internal thermo-regulator system – might not be present until hypothermia has set in, and an onslaught of symptoms suddenly arise.

So How Can a Diver Avoid Hypothermia?

Through a combination of prevention and awareness. Just being aware that it can occur, and knowing what symptoms to look for, is a giant first step to stopping hypothermia before it sets in.

These symptoms are general, but noticeable with a little vigilance, and can include:

  • A mild feeling of confusion
  • Varying difficulty with motor control
  • Constant shivering, and just being cold

When this occurs, go to the surface immediately, dry off, and spend more time on the boat that you normally would just warming up. (Even if it means missing a secondary dive that’s scheduled soon after your last one.)

As prevention, there are a few steps divers can take:

  • Be wary of long dives, or at least vigilant. The longer you’re in the water, the more likely it is for your core body temperature to drop to dangerous levels.
  • Bring plenty of dry clothes for when you get out of the water, or bring along a jacket to wear over your wetsuit in between dives.
  • Stay away from heavy drinking before a dive. It might feel warm going down, but alcohol can actually speed up the internal heat loss process.
  • Invest in exposure protection, and wear more than what you think you’ll need, (a hood will especially come in handy.)

With warm weather hypothermia, just being aware that it can happen in tropical climates is a good start to avoiding it. Have an arsenal of protective gear, give your body opportunities to warm up after a dive, and stay attuned to the signs your body is telling you. With a little common sense, it’s easy to avoid this surprising, but very real, risk.

Need a new wetsuit? Scuba Toys has a massive selection of wetsuits, boots, gloves and hoods for women and men!

Have you ever experienced hypothermia while diving? Let us know in the comments section below!

Article Name
Think Hypothermia Is Only a Cold Water Risk? Think Again.
We all know hypothermia is a risk while diving in cold water, but it can also occur even in the tropics. Here's how to avoid developing warm water hypothermia.

3 responses to “Think Hypothermia Is Only a Cold Water Risk? Think Again.”

  1. Joe says:

    I’ve encountered plenty of divers who’d rather look “cool” or not be inconvenienced by proper dive gear in my 20+ years. However, I make the safety a priority. No sense in unnecessarily risking my life or the lives of those who would try to save me.

  2. Solomon U. says:

    I was with a man on a boat who got hypothermia once. It was certainly a scary but avoidable problem.

  3. Trish says:

    I’m relatively new to diving and would’ve thought that I didn’t necessarily need all of my gear in certain areas. Thankfully, my courses and reading have taught me otherwise.

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