Hypothermia and Effects On Seafarers – What You Must Know

Hypothermia is a condition that results when a body is exposed to extreme cold weather condition. When a ship’s crew member falls in to the water by accident or is exposed to extreme condition while working on deck, it has been observed that majority of the times a fatal condition is reached because of hypothermia.

Hypothermia will occur when the temperature of human body temperature falls below 35℃. The mortality rate of hypothermia ranges from 20% to 90%, hence looking at the numbers, it can surely be considered as a dangerous condition.

Depending upon the temperature of the surrounding, i.e. air and water temperature, the time taken by a body to reach the hypothermia state will vary.

Usually, there can be two situations when a person is exposed to hypothermia:

Accidental Hypothermia: If a person meets with an accident i.e. falling in cold water, exposed to extended extreme weather etc.; such unforeseen situation can lead to hypothermia. 

Secondary Hypothermia: If a person has already been ill or in poor health condition, consuming wrong drugs, or is in poor recovery condition, it can lead to low body temperature, causing secondary hypothermia. 

As seafarers work near water and sometimes in cold regions, they are more prone to accidental hypothermia. 

In case of man overboard accident in cold water or extreme cold weather, the survival instinct of a human will keep him/her afloat but hypothermia will lead to major drop in body temperature and senses, eventually leading to drowning or unconsciousness.

Understanding Hypothermia

Hypothermia is a combination of two different word- “Hypo” meaning water and “Thermia” meaning temperature. The words are combined to form what describes a body condition wherein the temperature within the body drops below the normal temperature required for proper functioning of the human body.

The human body maintains a temperature of 36-37℃ in normal conditions using hypothalamus, a central part of the brain which monitors the body temperature using nerves.

The hypothalamus will contract and expand the blood vessels to control the flow of the blood to adjust and maintain the body temperature.

However, if the body is involved in an accident or it has been long exposed to extremely cold conditions, the brain will not be able to make the adjustments, leading to reduction in body temperature or hypothermia. 

Image for representation purpose only
Image for representation purpose only

There are mainly three stages of hypothermia, depending upon the drop in body temperature and the body’s metabolism rate. They are –

1. Mild Hypothermia

 Mild hypothermia occurs when the body temperature drops to 35-32  ̊°C. The effects of mild hypothermia are:

  • It suppresses the functionality of the central nervous system
  • It impairs the decision making capabilities
  • It reduces the feeling ability making the movement slow
  • Shivering of the body 

2. Moderate Hypothermia

Moderate hypothermia happens when the body temperature drops to 32 – 28  ̊°C. The effect of moderate hypothermia are:

  • Alarming suppression of the central nervous system which impairs the conscious ability of the person and can result in coma
  • Slowing of heartbeat and hearts pumping ability reduces
  • Difficulty in breathing, leading to reduction in the oxygen levels
  • Different organs such as heart, lungs, and nervous system gets affected
  • Reduction in the proper functioning of the digestive system, leading to intestinal obstruction
  • Rigidity in the muscle, making it difficult to move 

3. Profound Hypothermia

Profound or severe hypothermia is an alarming state when the body temperature drops below  28̊°C. The effects of profound hypothermia are:

  • It can lead to coma, heart and respiratory failure
  • The blood pressure will become too low in a short period of time
  • When the person is in profound hypothermia state, the chances of recovery reduces; however, resuscitation and other relevant methods can help in recovery if performed instantly

If the body temperature drops below 22°C, the person will be unable to breathe any further and reduction of body temperature below 20̊°C will lead to cardiac arrest. 

Different Ways Seafarer Can Get Affected by Hypothermia

Seafarer onboard ships work in various temperatures and weather conditions. They can experience hypothermia:

  • When the seafarer fells in water i.e. during man overboard situation. The scenario will be more hazardous if the water temperature is cold or if there is ice in the region
  • Seafarer working out on deck in a cold region without proper winter wear
  • Seafarer working in sever cold region (e.g. Russia in winters) without any warm clothing
  • Seafarer working inside cold storage room for a long time without warm clothing

Under hypothermia, seafarer’s physical condition will vary as a person not having food or working under the influence of alcohol will have less ability in the body to increase or maintain the body temperature

Actions To Take When Seafarer is Under Hypothermia:

As explained above about the different ways seafarer can be affected by hypothermia, let us assume if the seafarer fells in water. In such cases, the following things to be done immediately by the ship’s staff:

  • Take the person out of water as soon as possible 
  • Provide a thermal protective aid or TPA to the victim
  • If the victim’s respiratory function is affected, start providing cardiopulmonary resuscitation while blowing five times into the mouth of the victim, (while two times is the generally accepted practice, in the case of respiratory failure due to drowning, five times is more suitable in order to clear the airway obstruction)
  • If due to drowning, the victim’s heart has stopped, performing heart massage at a rate of 100 – 120 times per minute. Use the AED if available
  • Once the cardiopulmonary recovery has been achieved, it is extremely important to warm the body using a blanket and TPAs
  • Shift the person to a shore hospital if necessary, in case the situation allows

Effects of Hypothermia

A normal human body temperature is considered to be at 35-37 ̊°C. If the body temperature drops below this, the condition of hypothermia is reached. Effects of hypothermia are:

  • Shivering of body to compensate the heat loss
  • The blood flow will reduce inside the body
  • Numbness of hands and legs
  • Loss of senses
  • Effects decision or judgement making of human mind due to reduction in mental dexterity
  • Inability to swim
  • Unconsciousness when body temperature reaches below 30 ̊°C
  • Pale Skin colour
  • Limbs become stiff
  • Pupil dilates and do not react to light
  • If temperature drop rate increases, it will lead to irregular heartbeat with difficulty in pumping blood
  • Profound hypothermia leads to death

How to Prevent Hypothermia?

It is very important to wear personnel protective cold gear when working in cold atmosphere. Following precautions must be taken onboard to prevent hypothermia-

  • Always wear thermal protective gears while working out at deck in cold weather.
  • When abandoning ship during emergency situations, immersion suit must be worn when outside temperature is low.
  • If a person falls in water, try to rescue him/ her as soon as possible
  • Also, use thermal protective aid when rescuing a person from sea water.

Disclaimer: The authors’ views expressed in this article do not necessarily reflect the views of Marine Insight. Data and charts, if used, in the article have been sourced from available information and have not been authenticated by any statutory authority. The author and Marine Insight do not claim it to be accurate nor accept any responsibility for the same. The views constitute only the opinions and do not constitute any guidelines or recommendation on any course of action to be followed by the reader.

The article or images cannot be reproduced, copied, shared or used in any form without the permission of the author and Marine Insight.

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About Author

An ardent sailor and a techie, Anish Wankhede has voyaged on a number of ships as a marine engineer officer. He loves multitasking, networking, and troubleshooting. He is the one behind the unique creativity and aesthetics at Marine Insight.

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