Written by Paul Newman, 11th Coast Guard District Recreational Boating Safety Specialist
It was a beautiful summer day on Lake Tahoe. The air temperature was 75 degrees and the water about 60 degrees on the surface. It was his first time on a stand-up paddleboard, or SUP, and he knew he was supposed to carry a lifejacket. So he tied it to the top of the board with the leash that should have gone around his ankle. About 50 yards off the beach he lost his balance, fell off the SUP and drowned instantly.
What happened? How can someone drown so fast without even struggling to swim on the surface? Witnesses said he didn’t hit his head, so what happened?
What he likely experienced was cold shock response, the first stage of cold water immersion. The sudden fall into cold water made him gasp underwater. Aspirating water he began choking, probably panicked and, sinking into even colder deep water, made ineffective, frantic movements with his arms which had been momentarily stunned by the cold water. He wasn’t wearing a lifejacket and he died without ever surfacing.
That “gasp reflex” is one we all have experienced either in a cold shower or jumping into a cold pool. And “cold” means water less than 70 degrees. According to the U.S. Water Fitness Association swimming pool water should be 80 to 90 degrees. Our body temperature is 98.6 degrees It’s no wonder we gasp when the water is 60 degrees! And in winter these symptoms are only made worse by colder water.
Research has shown that this is probably why many boaters, fishermen, hunters, and others drown so quickly. Cold Water Boot Camp USA was a 2008 research project of theNational Water Safety Congress, funded by a Coast Guard grant to understand what happens in the first few minutes of being exposed to cold water. They took eight volunteers, including a Coast Guard rescue swimmer, and had them jump into 45 degree water to see what happened.
They all experienced the symptoms of cold shock response: an initial gasp, hyperventilation, and extreme difficulty swimming. Since they knew they were going in the water they were prepared, but some couldn’t even swim the length of a 25-foot Coast Guard boat without needing help.
If they calmed themselves and stayed in the water a few minutes longer they experienced the second phase: cold incapacitation (not to be confused with hypothermia which takes much longer). After about 10 minutes their fingers and arms stopped working and they couldn’t climb back onboard a boat or help themselves. They also succumbed to swim failure: their arms and legs couldn’t make effective swimming motions to keep them afloat. They would have drowned if they hadn’t had rescuers nearby to hold them up.
They took a few people – wearing lifejackets – all the way into mild hypothermia and that took a lot longer than most people think. It takes an hour or more for hypothermia to take full effect (depending on water temperature, body composition, etc.) and another hour after you lose consciousness for your heart to stop. Without a lifejacket or something to keep you afloat you’ll drown before you die of hypothermia.
There is more research on the Cold Water Boot Camp USA website, but they summarized the three stages of cold water immersion with the 1-10-1 Principle:
• 1: Cold Shock (first minute)
- o Gasp reflex (inhaling or aspirating up to a quart of water if underwater
- o Hyperventilation (rapid, uncontrolled, ineffective breathing)
- o Drowning if you can’t calm yourself.
• 10: Cold Incapacitation (after 10 minutes or more, if able to survive cold shock)
- o Loss of muscle dexterity (can’t get back in the boat, operate radio, etc
- o Swim failure (can’t swim, no longer a “strong swimmer”)
- o Drowning if not rescued
• 1: Hypothermia (after one hour or more)
- o Only if wearing a lifejacket.
Now let’s pair this research with a new slogan to promote lifejackets:
“A Lifejacket Buys You Time.”
1: Cold Shock
“A lifejacket buys you time to catch your breath.”
10: Cold Incapacitation
“A lifejacket buys you time to rescue yourself”
1: Hypothermia (only after an hour or more)
“A lifejacket buys you time to wait for rescue.”
Still not convinced?
A week after the man on the SUP drowned on Lake Tahoe a 17-year old boy drowned on the same lake. He was with a bunch of friends who all begin to panic in the cold water while swimming 25 yards back to their boat from a small island. While rescuers from the boat tried to get lifejackets to the boys the 17-year old drowned. He experienced swim failure caused by cold incapacitation.
So let’s change the conversation about lifejackets using what we know about cold water immersion: “That water is cold and will make you gasp if you fall in. Wear a lifejacket because a Lifejacket Buys You Time.”
Time to catch your breath (1 minute)
Time to rescue yourself (10 minutes)
Time to wait for rescue (1 hour or more)