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Be Aware of Cold Water Immersion

Summer is here and after a snow-packed winter, locals and visitors alike are ready to get out and enjoy Lake Tahoe. Whether out on the water, lounging on the beach or hiking to a rock outcropping to take a plunge, there are important precautions to keep in mind with water surface temperatures and cold water immersion.

Lake Tahoe’s temperatures are on the colder side at the beginning of the summer, ranging between 50 – 60 degrees Fahrenheit. Although these temperatures will continue to rise to 65 – 75 degrees as the days get hotter, keep in mind that symptoms of cold water immersion can occur at water temperatures as warm as 77 degrees. There are four stages to cold water immersion:

Stage 1: Initial Cold Shock
Sudden immersion into cold water can cause immediate, involuntary gasping for air, panic, and vertigo as well as create changes in your body's blood pressure and heart rate. The sensation of taking your breath away can result in panic and inhalation of water and drowning. If you do fall in or enter the cold water, attempt to get control of breathing and try not to panic. Focus on floating with your head above water, until the initial cold shock phase passes.

Stage 2: Short-Term Swim Failure
Swim failure occurs anywhere from 3-30 minutes following the initial cold water shock. In this phase, the muscles and nerves in the legs and arms will begin to cool quickly, causing strength and movement to drop significantly. This stage of cold water immersion can render a strong person unable to pull themselves out of the water or keep their head above the water.

Stage 3: Long-Term Immersion Hypothermia
Hypothermia sets in after 30 minutes of cold water exposure, depending on the water temperature; as cold water causes the body to lose heat 25 times faster than cold air. Hypothermia is a cooling of the body’s core temperature caused by active heat loss and the failure of the body to produce more heat. Recognize signs of hypothermia to help identify its early onset: shivering slurred speech; cold and blueish lips, skin and fingernails; loss of feeling in extremities; confusion; dizziness and rigidity in extremities.

Stage 4: Post Immersion Collapse
Post immersion collapse can occur at any point. Your body is still in danger while being rescued from cold water or after. Cardiac arrest after cold water immersion occurs due to the collapse of the arterial blood pressure. Along with hypothermia, possible water in the lungs due to inhalation, or coagulation issues due to cold and thickened blood.

To have a fun, safe time on the water, practice simple “dos” and “don’ts” such as making sure to wear a personal flotation device at all times and if you’re operating a boat, ensure there are life jackets for every passenger aboard. Don’t jump off large rocks into deep water, as this runs the risk of increased cold water immersion and trauma based off the height of your jump.

Recognizing the four stages of cold water immersion and signs of hypothermia prevents emergencies, injuries and helps to keep you and your family safe around the lake this summer.

Kristi Kimball, RN, BSN, is the Trauma Program Manager at Barton Health. Barton’s Level III Trauma Center is a critical medical facility for Lake Tahoe offering resources for trauma care and the immediate availability of emergency medicine physicians, surgeons, nurses, lab and x-ray technicians, and life support equipment 24-hours a day.