How to Do Cold Open Water Swimming Safely

Pools closed during the COVID-19 pandemic led many swimmers to dive into the open water. But training in rivers, lakes, seas, or oceans requires swimmers to not only adapt to waves, currents, and boat traffic but to cold temperatures in some places.

If you’re still unable to swim in your pool, or you want to give cold open water swimming a try, here’s how several Masters swimmers prepared for a cold, but safe, swim.

Before trying cold water swimming, you should consult with a medical professional to determine whether it’s something you should pursue.

Swimming Gear and Adaptation

When pools around her closed, Palm Beach Masters member Eney Jones went into Colorado rivers and lakes for swimming solace. Mid-winter water temperatures were frigid, and snow and ice surrounded her swimming spots, so she, like many cold water swimmers, used gear. Jones wears a full-body wetsuit and a neoprene swim cap.

Liz Carlin, a member and captain of the Long Beach Grunions, does the same and sometimes wears gloves and booties when she goes into the Pacific Ocean. She recommends swimmers trying cold water swimming use ear plugs.

In addition to using this gear, it’s recommended that you wear a brightly colored swim cap, use a brightly colored tow float, and never swim alone.

Adapting to the cold water is another important safety precaution. Don’t jump in expecting to swim for 45 minutes. Instead, build up how long you’re in the water gradually so your body can acclimate to how cold the water is.

To acclimate before each swim, Jones wades in slowly.

“I went through stages of being frightened and then feeling incredibly alive,” she says. “You have to clear your head and focus on your heart rate and breathing.”

Carlin adopts a similar method. She enters the water slowly, allowing her body to get comfortable. She then splashes water onto her face and then swims about 50 meters, stops, treads water, and checks in on her breathing.

Cold Water Dangers

When you swim in cold water, your body experiences many changes: Your surface blood vessels constrict, your blood pressure goes up, and your breathing rate increases. You can experience hyperventilation, cardiac arrest, stroke, drowning, or hypothermia, all major medical conditions that can lead to death.

Jones and her swimming buddies watch each other for blue lips and slurred speech, sure signs that they need to get out and start getting warm immediately.

Colonials 1776 member Diana McManus experienced a hypothermia wake-up call when she did a 24-hour relay event in San Francisco three years ago. People weren’t using wetsuits in the frigid water, something she decided to try.

“The first swim went great,” McManus says. “Despite initial shock, I began to enjoy the 53-degree water.”

She experienced dizziness and nausea on her second swim, symptoms she instantly recognized as warning signs. Afterward, she sat in a sauna, shivering nonstop, and felt hot and cold at the same time.

“I went in rushed,” McManus says. “I didn’t take the time to prepare mind, body, and spirit for the adventure.”

But sometimes cold water swimmers can’t prepare themselves enough for an open water swim. Recognizing when to stop early, she says, is important.

“If I feel queasy or lightheaded, I stop,” McManus says. “I’ve gotten to where I can tell when I’m reaching that point. Better to get out while I’m still clear-minded than try to be a hero and then perhaps put myself or possibly others at risk.”

Warming Back Up

Warming up is important after a cold swim.

Carlin pours hot water over her as she takes off her wetsuit following her swim. She then puts on dry clothes, a knit hat, and either a parka or large jacket before drinking hot tea.

Jones downs a hot thermos of chicken broth, hot chocolate, or hot tea post-swim.

“Having something warm to drink is just huge,” she says.

McManus says her parka is important.

“My Dryrobe was the best $100 I spent on eBay,” she says. “Not only does it keep me warm, but it’s easy to change clothes in mixed company. I keep my cap on until I dig out my ‘land’ hat. Getting out of wet clothes is really important. When you first get out, you might feel fine, but it doesn’t take long to experience after-drop [a continued fall of body temperature during rewarming after experiencing hypothermia].”

New England Masters Swim Club member Michael Leake doesn’t use a wetsuit, even as the waters around his Vermont home reach the low 40s, which places even more importance on his plan for getting warm again.

“Having a plan for rewarming is crucial,” he says. “I don't always think clearly when getting out and have just minutes before my hands don't work.”

His swim bag sits on shore with two towels and clothes stacked in the order that he puts them on: T-shirt, sweatshirt, sweatpants, socks, shoes, jacket, winter hat, and gloves. He then sips hot tea while walking to his car and then lets the sun or heater warm him up as he eats a granola bar or small candy bar while sitting in his car.

He avoids hot showers right after because they sometimes make him feel dizzy or sick. If he’s still cold when he gets home, Leake spends more time warming up.

“I sit under a blanket by the wood stove until I'm feeling warm, which can take up to an hour,” he says.