If you ask me, the worst part of scuba diving is putting on a Neoprene suit. It’s supposed to be worn close to the skin, and shield you from the cold, so it can be several millimetres thick, while being really, really tight.

The guys won’t know their pain until they’ve tried it, the girls might relate to the following comparison: you know what a hassle it can be, to pull up stockings without ripping them off? Well, imagine putting on a full body length, 5 to 7 millimeters thick stocking.

And if you’re doing this in warm weather, by the time you’re done, you’ll be sweating bullets.

Suit Up, Or You’ll Chill ‘Til You Shiver

As painful as this step may be, it is an absolute necessity if the water you intent to dive in is colder than 25°C.

Above 25°C, you might be comfortable enough to dive in a shorty, but beware of cold currents that might affect water temperature down below.

But to the occasional swimmer, 25°C doesn’t sound that cold at all, does it? You would probably be comfortable bathing in much cooler waters, anything above 20°C might sting a little when you try to get in, but you wouldn’t mind swimming in that.

Even when you swam comfortably in cooler waters, how long did that last? Did you spend more than 30 minutes fully immersed? If you have been training-swimming, doing a non-stop effort, then you might have lasted that long, even longer.

But if you were juste enjoying the feel of the water surrounding your body, I’m willing to bet you got out a lot earlier, because you were getting cold.

Water absorbs your warmth

This happens because water absorbs your warmth more than 20 times faster than air does. Let’s say you’re standing outside, naked, and it’s 20°C. It will take a while for you to be cold, like, teeth-clattering cold.

Step into a 20°C bath, and wait for it: you will feel cold a lot faster, and you will need to get out of there under 60 minutes, shivering.

Our normal body temperature hoovers around 37°C, and we don’t handle well any upset of that balance. A few degrees higher is a fever, a few less is hypothermia. A lot less becomes a life threatening situation.

So if you immersed your 37°C body of warmth in colder waters — and by the way, anything below 21°C is considered cold, you will cool down pretty quickly.

When scuba diving, it’s common to be immersed in waters cooler than 20°C, which is why we suit up carefully before we go. Even if this really is my personal worst feeling related to scuba diving, here’s why you shouldn’t pass on a good, temperature-appropriated wetsuit.

Why You Shouldn’t Risk It?

Hypothermia can quickly become life-threatening. I cannot emphasise more on that point, because I myself am — or rather, was, the type of person who can just fight off feeling cold by telling my brain that we’re imagining it: I am not cold. Let’s move on.

But underwater is not my middle school playground: feeling cold won’t just ruin my recess time, it might make me lose control and end up in an accident.

How To Tell You’re Too Cold?

After living in Canada for a year, and watching temperatures drop below -30°C, I became accustomed to ignoring the first signs of feeling cold (as it would be a permanent state, all winter long…)

So when I took up scuba diving, I had to teach myself to recognise these symptoms and stop ignoring them.

1. You’re Losing Interest In The Dive

The group is not moving fast enough. Time isn’t moving fast enough. You’re bored, but more like angry-bored. Yeah that’s a fish, you’ve seen hundreds of them. What, another small stuff on the rock? Don’t see, don’t care, can we move along now?

Yep. You’re cold. Your brain is telling you that there’s NOTHING down here, especially nothing worth freezing off your butt. Shall we get out of there, then?

2. Your Fingers Are Numb

When you get cold, the warm blood tends to concentrate in the vital areas of your body. Your head always gets its supply, then your core gets most of the rest, so your chest & vital organs all stay warm and irrigated. All extremities and non vital parts will get less blood flow, and will be more exposed.

If you’re having trouble moving your fingers, you’re lacking dexterity… The cold is setting in, and your body is already taking steps towards survival.

3. Your Teeth Are Clenched On The Regulator

You are probably shivering, or just about to. Shivering is the body’s jumpstart mechanism to trigger muscle movement. It shakes you up so your muscles get into action, in a attempt to warm you up.

If you’re keeping clenched teeth around your reg, you’re still in control. Beware, because the next step can be uncontrollable shivering, and you don’t want to lose control of your face muscles, especially not the ones holding on to your regulator!

4. Your Air Consumption Skyrocketed

…But your probably missed that, since you’ve stopped paying attention to your monitors a while ago.

By now, your heart rate has slowed down. And you’re in a serious risk of passing out.

How To Avoid Hypothermia?

Luckily, like most life-threatening hazards of scuba diving, hypothermia is easily preventable.

1. Choose Your Gear Wisely!

When choosing a wetsuit, ask about the diving conditions. What’s the water average temperature? Pay attention to the lowest estimates: maybe it will be warmer than expected, but better this than the contrary.

It’s also relevant to ask about the kind of dive you’ll be doing: if you’re going to explore a wreck deeper than 20 meters, you may want a warmer suit than if you’re doing a drift dive above the thermocline.

If you like the small stuff, or if you like to find a good spot to stare at the blue waiting for a big fish to show up, it may be wiser to suit up even if warm waters. I for one, enjoy swimming around a lot, moving quite a lot, so I find myself comfortable enough in a shorty, even down to 25°C.

2. Adapt Your Dive

So you jump in, but by the time you reach the bottom, the water is colder than expected. A lot colder!

Instead of biting through it, gather your group (or just your buddy) and maybe change the dive profile. If it’s too uncomfortable to be shark-sighting by 30 meters, you’ll come back another time.

Move up the coral gardens above the thermocline, where the water will feel a lot warmer.

3. Communicate!

It’s OK to feel cold! It’s not to hide it, and let your buddy wonder what’s wrong with you when things start to get bad.

Personally, I use 3 degrees to signal cold to my buddy. I rub my arm (like « brrrrr! »), and then:

1. One finger: I’m cold, but it’s ok. Let’s not stay static for too long please.
2. Two fingers: ok I’m COLD. Can we move along, and go up a bit, to warmer waters?
3. Three fingers: that’s it, I’m cold, I need to get out of here please.

You should talk to your buddy about cold-related communication before the dive!

— Be Well Prepared —

To wrap it up, my general advice is to be prepared for the eventuality of cold water. Choosing the right gear and establishing communication signs are a way to prevent and handle a situation.

Staying warm before a dive is another one: if you’re already cold on the boat, prior to diving, believe me, it won’t get better in the water. (That’s actually amongst the most idiotic bullshit I’ve heard divers say, by the way: « I’ll warm up in the water! ». Nope. Nope you won’t).