Hypothermia Isn't Just a Cold Water Hazard, 80°F Can Get You Too – Surf-fur

Hypothermia: A Cold And Warm Water Hazard

men swimming in cold water

In this post, we will explain the definition of Hypothermia and how to
stop it from ruining your watery experience. If you just want to get right to the point, go get yourself a Surf-fur Waterparka and make sure you wear it before and after immersion in water (any water below  75 degrees can cause Hypothermia) and even in between swims or dives to rewarm. 


woman using surf fur waterparka


Hypothermia claims the lives of roughly 25,000 people each year in the United States. If you are going to be enjoying nature and all her elements, especially the cold seasons, you should know the basic signs & symptoms of hypothermia, as well as how to prevent & treat it should it occur. We will share these basic causes and tips on how to treat the shivers if you do become exposed.

What is Hypothermia?

Hypothermia is a medical emergency that occurs when your body loses heat faster than it can produce it, causing dangerously low body temperature. Normal human core body temperature is 37°C (98.6°F). Hypothermia sets in when the core temperature falls below 35°C (95°F), which isn’t much of a drop!

Hypothermia is most often caused by exposure to cold weather or immersion in a cold body of water. When exposed to these elements and our body temperature drops, your heart, nervous system and other organs can’t work normally. If left untreated, hypothermia can eventually lead to complete failure of your heart and respiratory system and to death.

The actual cause of death in cold water is usually the bodily reactions to heat loss and to freezing water, rather than hypothermia itself. For example, plunged into freezing seas, around 20% of victims die within 2 minutes from cold shock, (uncontrolled rapid breathing, and gasping, causing water inhalation, massive increase in blood pressure and cardiac strain leading to cardiac arrest, and panic); another 50% die within 15–30 minutes from cold incapacitation (inability to use or control limbs and hands for swimming or gripping, as the body “protectively” shuts down the peripheral muscles of the limbs to protect its core), and exhaustion and unconsciousness cause drowning, claiming the rest within a similar time.

Causes of Hypothermia:

  • Cold Water Temperature: Cold water below 70°F (21°C), acts as a rapid heat absorber, causing the body to lose warmth 10 times faster than in air of the same temperature.

  • Wind Chill Factor: Wind speeds up heat loss by removing the insulating layer of warm air you have around your body and increases evaporation of water off the surface which is also called evaporative cooling. This would be the opposite of rewarming!

  • Wet Clothing: Wet or damp clothing, especially cotton, cools the body as it loses its insulating ability, allowing cold to seep in.

  • Immersion Duration: The more time spent in cold water, the higher the hypothermia risk. Even brief exposure can be perilous, especially in icy waters.

Recognizing Early Signs

Early symptoms of hypothermia include shivering, numbness, pale skin, slurred speech, confusion, fatigue, and impaired movement. Rapid identification of these signs is paramount, as prompt action can prevent worsening. Ignoring symptoms can lead to unconsciousness and death. Therefore, understanding and vigilance are crucial when navigating cold or water-related environments.

This is how fast hypothermia can occur in various environments: 

Water Temperature (Fahrenheit) Exhaustion or Unconsciousness Expected Time of Survival
32.5 degrees Under 15 minutes Under 15 to 45 minutes
32.5 to 40 degrees 15 to 30 minutes 30 to 90 minutes
40 to 50 degrees 30 to 60 minutes 1 to 3 hours
50 to 60 degrees 1 to 2 hours 1 to 6 hours
60 to 70 degrees 2 to 7 hours 2 to 4 hours
70 to 80 degrees 2 to 12 hours 3 hours to indefinite
Over 80 degrees Indefinite Indefinite


If you're surfing in cold water, you need to be aware of these timelines as well.


What’s the Difference Between Cold & Warm Water Hypothermia?

Recognizing the distinctions between cold and warm water hypothermia is crucial for safety. While cold water hypothermia is well-known, warm water hypothermia presents a hidden danger, especially in warm climates.

Cold Water Hypothermia

Cold water poses the most significant & common threat of hypothermia because of its ability to sap body heat rapidly. Immersion in cold water causes a significant drop in core body temperature. The symptoms begin with a cold shock, followed by cold incapacitation, and ultimately, unconsciousness. As the body loses heat, muscle control weakens, making it challenging to swim or move around easily. It’s almost as if you are moving through syrup.

Warm Water Hypothermia

Warm water hypothermia may seem counterintuitive, but it's a real danger. It occurs with prolonged exposure to water even a few degrees below our normal body temperature. Water measuring below 95 degrees will cause the body’s core to drop to unsafe levels and begin the process of long slow hypothermia. Surprisingly, high air temperature, prolonged immersion in warm water, and lack of awareness can all contribute. Symptoms may include shivering, confusion, muscle cramps, slurred speech, and drowsiness. The key takeaway here is that the process is way slower than cold water hypothermia, but it still has all the same symptoms. 

How to Prevent Hypothermia

Preparedness and prevention are your best allies in avoiding the dangers of hypothermia, whether you're in cold or warm water environments. Remember, just because the water is warmish, it doesn’t mean you are completely safe from the dangers of low slow cooling. 

Safety Guidelines for Cold and Warm Water Activities: 

  1. Wear a wetsuit that fits well. One that is too big will let a lot of water in and could drag you down. One that is too tight will constrict your blood flow and cut off the circulation to your extremities. This could even cause frostbite if the blood flow is cut off and the skin is exposed to the cold for a prolonged period of time. Booties, gloves and hoods all made with neoprene also help with the cold. Check out our cold water gear guide to see what else you'll need. 

  2. Never venture into cold water alone. Use the buddy system and, when possible, carry communication devices like radios or cell phones for emergencies.

  3. Learn basic water rescue techniques and have rescue equipment accessible, such as ropes, PFDs, and throw bags. 

  4. Appropriate clothing pre and post swim help to prevent hypothermia. Synthetic and wool fabrics are superior to cotton as they provide better insulation when wet and dry (think Surf-fur). Some synthetic fabrics, such as polypropylene and polyester, are used in clothing designed to wick perspiration and water away from the body (think Surf-fur again). Clothing should be loose fitting, as tight clothing reduces the circulation of warm blood. 

  5. Covering the head is effective, but no more effective than covering any other part of the body. While common folklore says that people lose most of their heat through their heads, heat loss from the head is no more significant than that from other uncovered parts of the body. Children have a larger surface area per unit mass, and other things being equal should have one more layer of clothing than adults in similar conditions, and the time they spend in cold environments should be limited.

  6. Applying warming devices externally, such as a heating blanket, can be good if an outlet is available. Blasting the heat in the car is always my favorite way to really heat up before a cold session.

  7. Placing a hot water bottle in both armpits and groin are recommended for moderate hypothermia.

  8. Active core rewarming involves drinking warmed fluids, irrigation of body cavities with warmed fluids, use of warm humidified inhaled air, and wearing a windproof warm parka or blanket that is made with synthetic materials. 

  9. Warm sweetened liquids can be given provided the person is alert and can swallow. Many recommend that alcohol and drinks with lots of caffeine be avoided. As most people are moderately dehydrated, warmed intravenous fluids to a temperature of 38–45 °C (100–113 °F) are often recommended.

  10. Maintain your core body heat and warm up in between dives as much as you can. Even if you are diving or swimming in tropical waters, you still need to rewarm your core whenever possible. It’s always colder down below.

  11. When the day’s cold water activities are done, reheat your body until sweating occurs. 

  12. Stay Hydrated and Avoid Excessive Exposure: Even in warmer waters, dehydration can occur. Drink plenty of water and protect yourself from prolonged sun exposure.

  13. Recognize Early Signs of Warm Water Hypothermia: Be aware of signs like confusion, muscle cramps, and nausea in warm water, as they may indicate warm water hypothermia.

How to Diagnose & Treat Hypothermia

Understanding the signs of early hypothermia and knowing how to treat them is critical to saving someone's life. Here's your comprehensive guide:

Recognize Symptoms

Watch for signs like shivering, confusion, slow movements, numbness, and pale skin. Signs and symptoms vary depending on the degree of hypothermia, and may be divided by the three stages of severity;

  • Mild - Symptoms of mild hypothermia may include shivering, increase in blood pressure, rapid heart rate, rapid breathing, and a pale skin. These are all physiological responses to preserve heat. Mental confusion, and liver failure may also be present. 

  • Moderate - Low body temperature results in shivering becoming more violent. Muscle mis-coordination becomes apparent. Movements are slow and labored, accompanied by a stumbling pace and mild confusion, although the person may appear alert. Surface blood vessels contract further as the body focuses its remaining resources on keeping the vital organs warm. The subject becomes pale. Lips, ears, fingers, and toes may become blue.

  • Severe - As the temperature decreases, further physiological systems falter and heart rate, respiratory rate, and blood pressure all decrease. This results in an expected heart rate in the 30s at a temperature of 28 °C (82 °F). Difficulty speaking, sluggish thinking, and amnesia start to appear; inability to use hands and stumbling are also usually present. Cellular metabolic processes shut down. Below 30 °C (86 °F), the exposed skin becomes blue and puffy, muscle coordination very poor, and walking almost impossible, and the person exhibits incoherent/irrational behavior, or even stupor. Pulse and respiration rates decrease significantly, but fast heart rates can also occur. Major organs fail and death occurs.

Immediate Actions to Take When Hypothermia is Suspected

  • Get the person out of the cold or water and into a warm, dry environment to halt further heat loss.

  • Strip off wet clothes and replace them with dry layers to prevent continued cooling.

  • Warm the person by wrapping them in blankets and applying heat packs to their chest, neck, and groin. 

  • Avoid sudden heat exposure, which can be harmful. Instead, opt for warm, non-alcoholic beverages and gradual exposure to a heat source.

If symptoms worsen, such as confusion or shallow breathing, call for medical assistance immediately.

In conclusion, by adhering to the basic safety measures and staying vigilant, you can significantly reduce the risk of hypothermia in both cold and warm water environments. As well, by knowing signs and symptoms of hypothermia, you can act swiftly to provide the proper treatment for hypothermia. Just keep in mind that preparation and awareness are the two most important factors to staying safe on the water. 




Mayo Clinic


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