Despite warm weather, it is essential to remember that the water can be frigid in many areas. Being immersed in cold water poses the greatest risk of hypothermia.
The risk of death for boaters and passengers increases significantly when the water temperature is colder in case of a capsize or a fall overboard. While water temperatures can vary depending on location and time of year, hypothermia does not require frigid water to manifest its effects. Even water reaching 77 degrees Fahrenheit may trigger an initial cold-water immersion reaction. As a result, boat operators must be fully aware of the impact of cold water immersion on the human body and prepared to respond accordingly.
Effects of Cold Water Immersion
There are four distinct physiological stages during which an individual reacts to being immersed in cold water and may become unconscious and die (Golden and Harvey 1981). Boaters familiar with the physiology of cold water immersion are better prepared to respond to an immersion emergency.
The effects of cold water immersion happen in four stages:
Cold Shock: This is the first stage in which the involuntary gasp reflex happens. The initial reaction lasts for about a minute and is characterized by a deep, uncontrollable gasp that results in hyperventilation. It is at this stage that the water enters the lungs.
Swimming Failure: In the next 10 minutes, there will be a loss of effective use of extremities, such as fingers, arms, and legs. There is no meaningful movement during this stage. Due to the high risk of drowning, even if the victim’s abilities are limited at this stage, victims must focus on self-rescue efforts and techniques.
Immersion Hypothermia: The term hypothermia describes a condition where the body’s temperature drops below 95 degrees Fahrenheit. The onset of immersion hypothermia depends on the victim’s water temperature, clothing, body type, and behavior. This stage is critical because the loss of consciousness may occur as briefly as an hour. Victims may die due to hypothermia even without the presence of drowning.
Post-Rescue Collapse: After being rescued from cold water, a person is at risk of cardiac arrest or lung damage. There may be heart problems after the cooled blood from the extremities travels throughout the body’s core. Fatal bleeding is also likely to happen at this stage.
The effects of cold water immersion can vary due to factors like age, body size, clothing, etc.
A comprehensive description of hypothermia and the four stages of cold water immersion can be found at www.watersafetycongress.org under the Cold Water Boot Camp.
Surviving Cold Water Immersion
Using a Personal Flotation Device is essential for survival in the water. A personal flotation device (PFD) allows you to remain afloat with minimal energy expenditure.
If you are required to enter cold water due to other immediate dangers, Controlled Entry is crucial to improve chances of survival:
Prevention of Cold Shock: Cold shock is the body’s immediate and often uncontrollable reaction to sudden cold water immersion. It can cause involuntary gasping, increased heart rate, and a spike in blood pressure. By entering the water in a controlled manner, you reduce the intensity of this cold shock response.
Avoidance of Injury: Jumping or falling into cold water can lead to injuries, especially if there are unseen obstacles below the surface. A controlled entry minimizes this risk.
Retention of Buoyancy Devices: If you’re wearing life jackets or other buoyancy devices, a sudden entry might dislodge them. Controlled entry ensures they remain in place and function as intended.
Breath Control is also critical for surviving Cold Water Immersion:
Prevention of Drowning: The gasping reflex can lead to water inhalation, increasing the risk of drowning. By consciously controlling your breathing, you can reduce this risk.
Reduction of Cold Shock Intensity: Controlled breathing can help calm the body and mind, reducing panic and the intensity of the cold shock response.
Conservation of Energy: Panicking and rapid breathing expend more energy, which is not ideal in a survival situation. Calm, controlled breathing helps conserve energy.
Delayed Onset of Hypothermia: While the primary concern during the initial stages of cold water immersion is cold shock (not hypothermia), conserving energy and keeping calm can help delay the onset of hypothermia in the subsequent stages.
The Heat Escape Lessening Posture (HELP) is a reliable survival technique for people who cannot immediately escape cold water or may not be rescued immediately. In the HELP posture, a submerged individual draws his knees to his chest and wraps his arms around his chest, hugging his life jacket tightly. By using this strategy, major parts of the body are protected from heat loss.
The HUDDLE technique is ideal for group situations. This method takes advantage of shared boy warmth and reduces the surface area exposed to cold water, thus slowing the onset of hypothermia and increasing the chances of survival and rescue in cold-water immersion scenarios. You put your arms over each other’s shoulders so that the sides of your chests are together. Keep exposed body parts, especially the head, out of the water as much as possible. Children and elderly persons are placed in the middle. Stay calm to reduce movement that would increase heat loss and deplete energy reserves.
Treatment of Hypothermia
Medical intervention must be performed to treat hypothermia. When medical intervention is unavailable, the most promising approach is gradually restoring the body’s normal temperature. Studies revealed that up to 20% of survivors die shortly after the rescue.
During an unexpected plunge into cold water or when it is necessary to enter cold water, the following guidelines can help improve the chances of survival:
Immediately remove the victim from the source of the cold. Cover him up to keep them dry. As you do this, remember that approximately 50% of a person’s body heat is lost through the head.
Remove wet clothes. Remove anything that may inhibit heat retention.
Concentrate on restoring the body’s normal temperature. Interventions may include as simple as skin-to-skin contact or sharing a blanket.
Never attempt to massage the victim’s extremities. If you do otherwise, it will only accelerate the rate of cooled blood traveling throughout the body’s core.
Never give coffee or tea. These stimulants may exhibit the same effect as a massage (which causes vasodilation).
Entering the water voluntarily should be done as slowly as possible.