What happens during stage 2 of cold water immersion?

Accidental cold water immersion (CWI) is one of the worst situations to encounter, especially when you aren’t prepared to deal with it. You need to realize that despite the common misunderstanding about CWI, it doesn’t directly cause the person to experience hypothermia. 

In reality, a couple of serious events occur before hypothermia starts setting in. In total, there are four stages of cold water immersion, including:

1. Cold shock response
2. Cold incapacitation
3. Hypothermia
4. Circum-rescue (post-rescue) collapse

In this blog post, we’ll keep our focus on the four stages of cold water immersion to understand what happens when you find yourself submerged in frigid temperature water.

1- Cold Shock Response

The initial cold shock occurs in the first three to five minutes, causing the person to experience involuntary gasping, hyperventilation, and vertigo. All of these conditions are the result of water inhalation and drowning. Moreover, the cold shock leads to sudden heart rate and blood pressure fluctuations, transitioning towards the next CWI stage – cold incapacitation.

However, by controlling your breath and not making any overhasty movements in the water, you can minimize the shock to a significant extent.

2- Cold Incapacitation (Short-Term ‘Swim Failure’)

The second stage usually occurs within three to thirty minutes following the cold water immersion, based on the individual’s initial cold-shock response. Your handgrip strength, manual dexterity, and swimming speed decreases by sixty to eighty percent during this period, which is not enough to pull yourself out of the water or even keep your head above water under rash water conditions.

3- Hypothermia

The long-term immersion hypothermia sets in after approximately thirty minutes of submersion in the cold water. However, the time factor also depends upon the exact water temperature, your clothing, and your behavior in the water. 

In simple words, hypothermia is the resulting factor when your body starts to lose heat faster than producing it, cooling your organs and leading to unconsciousness or death – with or without drowning. 

4- Circum-Rescue (Post-Rescue) Collapse

The fourth stage of cold water immersion happens before, during, or after the rescue. While you fight to stay alive in the cold water, the stress hormones surge through your body to help you survive. However, once the imminent threat minimizes, your mind relaxes, decreasing those hormones’ output. As a result, your blood pressure drops, and your muscles lose their functionality. It often leads to cardiac arrest while the person is still in the water.

Even when you’re out of the water, you can still be in danger of collapsing due to arterial blood pressure, leading to sudden cardiac arrest. Moreover, water inhalation can damage your lungs and cause problems to your heart as the cold blood from your arms and legs gets released into the body’s core.

Learning about the four stages of cold water immersion is the first step towards preparing yourself for the worst conditions. For more information regarding keeping yourself safe while indulging in various recreational water activities, you can visit our blog archives to surf through the informative content.

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There are four stages of cold water immersion. This is what happens in the first two stages.

• Stage 1: Initial “cold shock” occurs in the first 3–5 minutes of immersion in cold water. Sudden immersion into cold water can cause immediate, involuntary gasping; hyperventilation; panic; and vertigo—all of which can result in water inhalation and drowning. Immersion in cold water also can cause sudden changes in blood pressure, heart rate, and heart rhythm, which also can result in death.
• Stage 2: Short-term “swim failure” occurs 3–30 minutes following immersion in cold water. The muscles and nerves in the arms and legs cool quickly. Manual dexterity, hand grip strength, and speed of movement all can drop by 60%–80%. Even normally strong persons can lose the strength necessary to pull themselves out of the water or even to keep their head above water. Death occurs by drowning.

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There are four stages of cold water immersion. This is what happens in the last two stages.

• Stage 3: Long-term immersion hypothermia sets in after 30 minutes, at a rate depending on water temperature, clothing, body type, and your behavior in the water. The human body cools much faster in cold water than it does in cold air. Hypothermia occurs when your body loses heat faster than it produces it, cooling the organs in the core of your body. Hypothermia eventually leads to loss of consciousness and death, with or without drowning.

• Stage 4: Post-immersion collapse occurs during or after rescue. Once rescued, after you have been immersed in cold water, you are still in danger from collapse of arterial blood pressure leading to cardiac arrest. Also, inhaled water can damage your lungs, and heart problems can develop as cold blood from your arms and legs is released into the core of your body.

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Your chance of surviving cold water immersion depends on having sufficient flotation to keep your head above water, controlling your breathing, having timely rescue by yourself or others, and retaining body heat.

Prepare for boating in cold water conditions by always wearing a secured PFD. Also wear layered clothing for insulation. Equip your boat with a means for re-entry (ladder, sling, etc.) to use if you should fall into the water.

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Of course, the best prevention is to take all measures necessary to avoid capsizing your boat or falling into cold water in the first place. If you do fall into or must enter cold water:

• Don’t panic. Try to get control of your breathing. Hold onto something or stay as still as possible until your breathing settles down. Focus on floating with your head above water until the cold shock response abates.
• When your breathing is under control, perform the most important functions first before you lose dexterity (10–15 minutes after immersion).
• If you were not wearing a PFD when you entered the water, look to see if one is floating around you and put it on immediately. Don’t take your clothes off unless absolutely necessary. A layer of water trapped inside your clothing will help insulate you.
• Focus on locating and getting everyone out of the water quickly before you lose full use of your hands, arms, and legs. Try to reboard your boat, even if it is swamped or capsized, or anything else that is floating. Get as much of your body out of the water as possible. Even though you may feel colder out of the water, the rate of heat loss will be slower than if immersed in water.
• Be prepared at all times to signal rescuers.