Just float. Don't thrash.
Falling into cold water unexpectedly is something most people hope never to experience, but knowing how to handle it, if it ever happens, is a smart move. A video (below) released by the Royal National Lifeboat Institute (RNLI) in the UK, where ocean waters are cold enough to kill even in the summer, emphasizes the importance of floating, rather than thrashing, for the first minute or so.
Mike Tipton, a professor at Portsmouth University and an expert in cold water shock, worked with the RNLI to conduct floating trials in 80 people. Floating is the best way to cope with the cold water shock response, which is in fact a more immediate risk than hypothermia. Tipton says,
"When you first go into cold water, you get what we call a cold shock response. That means you have uncontrollable breathing and a sudden increase in the work of the heart. We have to fight that natural urge to thrash about or swim hard. It's much safer to relax and try and float for about the minute to 90 seconds it takes for the cold shock to disappear."
Interestingly, most people think they can't float, but Tipton challenges this assumption.
"We've done studies with the RNLI and the majority of people thought they couldn't float, whereas in fact when we got them to go into the water, they could. They majority of them thought that clothing would drag them under the water. They all floated easily when they were wearing clothing and easier still when they were wearing heavy clothing."
The reason is that clothing traps air, which boosts buoyancy. The less you move, the longer that air will remain trapped. Thrashing and swimming has the opposite effect, and you'll lose all buoyancy. One source says swimming or treading water will greatly increase heat loss and can shorten survival time by more than 50 percent.
After the cold shock response has subsided and your breathing is under control, you'll be in a better position to plan your next move, whatever it may be. You have two options: get out or do your best to survive. If you're in the water with other people, huddle to share body warmth. Try to protect the key body parts that lose heat the fastest -- the head, neck, armpits, chest, and groin -- and this is better accomplished by keeping your clothes on. Kick off shoes only if you must tread water for a prolonged period of time.
If you have a small boat, flip it over. Even a boat filled with water will likely be able to hold the weight of an occupant. If it cannot be flipped, get on top of it or pull as much of your body onto it as possible.
Falling through ice is a whole other experience. This is something I had to learn, growing up on a remote lake in northern Ontario where it was a real risk. In icy water, you don't have time to float, but it's still crucial to stay calm and get your breathing under control. You only have about 10 minutes until muscle weakness sets in, followed by muscle failure. Climb out as quickly as you can, starting in the direction you came from, since you know the ice was able to support you up until that point. Kick as hard as you can to propel yourself forward, like a seal in the Arctic would.
If you have anything sharp in your pocket (car keys, a pocket knife), jab it into the ice as far away as you can reach to help pull yourself out. (I used to carry two knives when crossing frozen lakes for this very reason and my dad often has a long stick.) A ski pole, a ski or snowshoe can give you something to climb up on.
Once out, roll away for a good distance before standing up. Then remove wet clothing (which may seem counterintuitive, but is the fastest way to warm up), start moving, and don't stop till you've reached safety. You will need a hot bath (105 to 110 degrees F), but do not allow legs or arms to dip into the bath, as this causes the cold blood in the extremities to rush back into the body and lower the core temperature further, resulting in death. This is known as "after-drop." If you don't have a bath, use heat vents in a car, a heating pad, warm towels, exercise, or a fire. The process of reheating should be gradual but steady, and can take several hours.
The best advice? Don't venture out on cold water or ice, unless you've tested its thickness. Always go with another person and take lifesaving gear, just in case you need it.
Watch the RNLI's 1-minute video on floating below: