Here are the answers to the knowledge test at the end of the water temperature chapter in book two.
1. What immediate physiological effects can occur when you’re immersed in cold water without an appropriate wetsuit or drysuit?
- Gasping for breath
- racing heart
- hyperventilation
- vertigo
- rapid blood pressure changes
2. What is the name of this first phase and how long might it last?
Cold water shock response (also known as cold shock response) and it can last for up to a minute.
3. If you remain in the water, what will happen next to your body?
Your body starts shutting down blood-flow to the extremities in order to conserve your core body temperature, and the nerves and muscles close to the skin lose functionality as they get colder.
4. What is the name of this second phase and when might you start to experience its effects?
Loss of muscular function, and you may start to experience its effects very quickly, within the first 10 minutes of immersion
5. What is the third main phase that your body will experience if you remain in cold water? What are the symptoms and when might you start to experience its effects?
Hypothermia occurs when your core body temperature drops below the level at which your vital organs can function properly. Possible symptoms include pale skin, blue lips, shallow breathing, confusion, irritability, slurred speech, incoordination (the ‘umbles’; grumbles, mumbles, fumbles and stumbles), and shivering (but maybe not – as hypothermia progresses the shivering will stop, which is a bad sign rather than good). Even in near-freezing water it takes at least 30 minutes for the body to cool to the point of becoming hypothermic, more likely closer to an hour.
6. What are the most important considerations when assisting a hypothermic casualty?
One of the worst things you can do with a cold water hypothermia victim is haul them up into a vertical position, which can lead to instant cardiac arrest. Try and maintain them in a horizontal position while getting them out of the water, and then begin the recovery process. The fundamental priorities are to remove wet clothes, get the casualty dry and into shelter, and then start getting warmed up. Warm drinks are OK but actually, sugary drinks are more important as the body needs calories. (Definitely no alcohol!) External heat can be applied to high heat transfer areas such as the underarms and sides of the chest. Be incredibly gentle with the victim throughout. Remove their wet clothes with the utmost care. Avoid any rubbing or chafing of the skin. Most importantly though, keep the victim horizontal. Laying down, not even sitting up. Even a mildly hypothermic victim should not be moving around for at least 30 minutes after treatment has started. Ideally you should call the emergency services and get a professional to talk you through what to do. It takes a long time to recover from hypothermia, the core temperature will continue to drop (the ‘after-drop’ phenomenon) for potentially many hours after treatment has started. You cannot rush this recovery.