Cold Water Safety
If you grew up in the Pacific Northwest, or anywhere else with cold waters, you often learn about hypothermia. What you may not know is that cold-water shock and swim failure are risks that come before hypothermia. Many drowning victims die within minutes of going overboard due to cold-water shock.
You may think this can't be true because people swim in cold water, do the 'Polar Plunge', or use cold-water therapy in sports medicine and they don't die. Those situations aren't accidental. Cold-water immersion is dangerous when you're in an accident (you're surprised to fall in the water) and you have a physiological response you cannot control due to the shock.
Choose to always wear a life jacket, it can literally save your life. The U.S. Coast Guard estimates 80% of boating fatalities could have been prevented if people wore their life jackets.
Risks of Cold Water Immersion
Safety experts define "cold water" as anything below 70 degrees. You should treat any water temperature below 60 degrees Fahrenheit with caution. Don't be fooled by warm air temps, because many Washington waterways stay under 60 degrees Fahrenheit most of the year.
Cold water is deadlier than you think. It can kill a person in any of the following four stages:
Stage 1: Cold Water Shock
Initial cold shock occurs in the first three to five minutes of accidentally falling overboard. You can experience immediate involuntary gasping, hyperventilation, vertigo and panic — all of which can result in water inhalation and death from drowning. A life jacket will help prevent water inhalation by keeping your head above the water. You may also experience sudden changes in blood pressure, heart rate and heart rhythm, which can result in death.
Stage 2: Swim Failure
Short-term immersion swim failure occurs three to 30 minutes following a fall overboard into cold water. The muscles and nerves in the arms and legs cool quickly. Manual dexterity, handgrip strength and speed of movement can drop by 60% to 80%. Even strong swimmers can lose the strength necessary to pull themselves out of the water or even keep their head above water. A life jacket will help keep you afloat when your body loses it's strength. A life jacket can help keep your core warm and keep you afloat if you loss consciousness.
Stage 3: Hypothermia
Long-term immersion hypothermia may set in after 30 minutes, depending on water temperature, clothing, body type and behavior in the water. Hypothermia occurs when the body loses heat faster than it produces, cooling vital organs. Cold water robs the body of heat 25 times faster than cold air. Hypothermia can eventually lead to loss of consciousness and death, with or without drowning.
Stage 4: Circum-Rescue Collapse
Post-immersion circum-rescue collapse occurs during or after rescue. Once rescued, people are still in danger of cardiac arrest. In addition, inhaled water can damage lungs, and heart problems can develop as cold blood from arms and legs is released into the body’s core.
Sources: Dr. Frank Golden and Professor Michael Tipton, cold-water survival experts.