When you get into the sport/hobby/passion that is SCUBA diving, you are made well aware of the risks involved, hence the multi-day process to get open water certified. You must understand how to read your gauges, understand hand signals, and be aware of your buddy in order to have a safe dive, for without this knowledge, you could be in real trouble if a problem should arise. But one aspect many divers neglect to plan for is exposure protection, especially when diving in bathwater-warm tropical locales. The delightfully warm waters of tropical destinations may seem safe and sublime, but they still carry one of the biggest risks of diving: hypothermia.
The practical definition of hypothermia, according to Webster’s online dictionary, is “subnormal temperature of the body.” In more specific terms, it is when the core temperature of the body dips below the degree necessary to run the body and its functions. That number’s lowest point is 35 degrees Celsius, or 95 degrees Fahrenheit. Since the human body typically operates at between 98 and 100 degrees Fahrenheit, sinking down to 95 degrees would most certainly have a noticeable effect. Symptoms of hypothermia include shivering, mental confusion, motor skill shutdown, and most severely, amnesia and death.
When your body is subjected to temperatures that are colder than your ambient body temperature, it begins to deal with the stress in several ways. First, you begin shivering, which is your body’s way of preserving heat. Your insulin secretion will drop, as will your cell consumption of glucose as your body tries to preserve energy for its functions. From there, as much as the temperature drops, you will begin to feel more severe symptoms. Disorientation, sluggishness, and loss of coordination are all very real symptoms of hypothermia, and the last place you want to discover that is on a dive.
So what can you do to avoid hypothermia? The solutions are all too simple to implement:
- Exposure Protection
No matter how warm the water seems, your body will still lose heat at a faster rate than it would on land, and depending on the length and depth of your dive, that heat loss adds up. Consider also the abrasion and sting protection even that little bit of neoprene or nylon offers you — many tropical divers swear by head-to-toe protection, sometimes even including gloves and beanies. There are many lightweight options on the market that offer a much better chance at avoiding hypothermia and other undersea ailments than a pair of trunks or a bikini would. - Keep Warm Before You Dive
If you’ve got a windy boat ride out to the dive site, make sure you stay bundled up to the extent where you feel cozy and warm, but not overheated. Keeping your upper body enclosed in a warm jacket or sweatshirt will do much to keep that radiated body heat near your core where you need it. - Trust Yourself
Never be afraid to call a dive because you’re too cold. If you’re feeling cold, chances are someone else may as well, so don’t ignore your body’s signals in order to not be the odd man out. Your body has very specific signals it sends for extreme conditions such as cold and heat, so pay heed and let your dive master know if you need to surface.
Hypothermia is an accepted risk of diving, but in no way should it be a deterrent for those who are new to or thinking of SCUBA diving. Taking the proper precautions and learning the safety steps will set you on a path of preparedness in your diving future.
Photos via IK’s World Trip, vibrant_art








I have seen it… important to strip all the wet clothes off!
Probably. Michigan’s waters in early spring sure as heck aren’t warm in a wetsuit!
thankfuly no
I dive in sub 60 water if not sub 50 water most of the year. That is always on my mind…its easy to take the correct steps to avoid it
I’m sure I did on a night dive one time in November. Wetsuit only in Northeast Pennsylvania, couldn’t feel either of my feet for a disconcerting amount of time after the dive.
close, dove in the Puget Sound in the middle of January, beautiful but cold as hell!
The coldest I’ve been in was 38 degrees
I feel silly admitting it but during my certification 11 years ago, I got hypothermia from an ill fitting wet suit. In Florida…..in April….in an indoor pool. Lol.
No. Had I no opted out of the 2nd dive, i would have.
No, but I was one of the few cadets wearing a drysuit when we ice dived. Lake Frederick at West Point. Surface support to include hot beverages, burgers, etc. after the dive made the experience more memorable. Plus, we did not stay under too long. A fond memory of the West Point SCUBA Club and how to avoid hypothermia. Best, Bruce NAUI Instructor #10683
Ive had hypothermia several times diving the north coast of california when I’ve stayed out too many hours abalone diving or spearfishing,it will make you lethargic, numb and wobbly but sometimes its hard to go back to shore when your seeing alot of large cabezon, lings and plate size rock scallops.Getting chilled to the bone comes with the turf on the north coast.the only way to stay warm is drysuit!dive skins do not work and will chill you faster
I came pretty close here.
http://en.wikipedia.org/wiki/Clear_Lake_(Linn_County,_Oregon)
Yes and it sucked! I dive in Puget Sound in Washington state and this Christmas I went diving with my dad and ALL 3 seals on my dry suit leaked and I froze. The water temp was around 42 degrees! It was extremely cold! (BUT we saw some awesome stuff so it was totally worth it)
On my second dive in the ocean while getting my cert. in Monterey I did. We were doing mask removals and I was cold but as soon as the water hit my face after taking my mask off, I lost it. I couldn’t figure out how to breath…
38 degrees in a wetsuit…swore I’d never do that again! Have nice drysuit now!
First thing I did after warming up was call my dive shop & order a dry suit.
35-43 degrees annual temp from the article preserves pre-historic trees at Clear Lake from the article. Now that’s cold!
I miss diving Washington State. Yes it was cold water, but now all I have is Oklahoma lakes. I need to get out more…
1 dive in wetsuit 5mil… Hawaiian Water, 76 degrees I dropped to 97.4 degrees..
Yes I am the Crazy Crazy that dives dry in Hawaii but if I dont I get to the point of uncontrolled shivering.
No…I am a warm water diver, however if I do dive in colder waters(and I have) I insure proper insulation for the temp both at surface and at depth.
Never, dive Bonaire, by the 3rd dive, wear a skin.
1st pool dive in Hawaii in 3mil jumpsuit & I was freezing. Bought a 5mil full suit before next dive, absolutely HATE being cold. Even the open water dives around Hawaii at 76-79 Deg, it gets uncomfortable about the 50 min mark, even when I have 20-30 min of air left, time to start heading up
Cold is me pet peeve. My Divemaster in school had a bumper sticker that said “I pee in my wetsuit”