One Star Diver (ISO)
Welcome to the Underwater World5 Tópicos
Diving Equipments6 Tópicos
Our First Contact with Water9 Tópicos
The Effects of Changes in Pressure4 Tópicos
Breathing with Scuba Set10 Tópicos
Limitations of Breathing Air Underwater3 Tópicos
Planing and Monitoring Your Dives6 Tópicos
After the Dive5 Tópicos
About the Practical Skills12 Tópicos
Although it depends on the place and time of year, the water temperature is almost always lower than the ambient temperature. Tropical waters have an average temperature of about 30º C, while in the Mediterranean it is between 13 and 25º C, and on the Cantabrian Coast between 10 and 20º C.
However, our body must always be kept at a temperature of approximately 37º C; to achieve this, our body has very effective heat generation and temperature control systems.
When we are submerged in water, our thermoregulatory system must cope with a change in the outside temperature within a few seconds. If this change is abrupt it could 1 cause shock, called “hydrocution”, dangerous fainting in 2 the water. Thus, exposing the body to abrupt changes in temperature must be avoided.
Therefore, we must enter the water with the body prepared for the dive.
To do so, first, we wet the back of the neck and the wrists so that the body becomes used to the temperature of the water. If this causes us to begin shivering, it’s a sign that we’re not fit to dive.
A wetsuit with a hood can protect us from sudden changes in temperature. However, we must avoid overheating before entering the water by staying equipped for a long time under the sun or exercising with the wetsuit on. If we do not avoid excessive heat, our body will be working hard to try to reduce its temperature and when entering cold water, there will be an abrupt demand to do the exact opposite (increase body temperature).
When we dive, our body continues to produce heat to maintain its temperature. However, the water in contact with the skin absorbs the heat very quickly. Water is 25 times more conductive of heat than air, so even water that at first feels warm will begin to feel cold after a few minutes.
The human body may not be able to cope with the constant heat loss, and therefore its temperature may drop. If we start shivering, we must exit the water, get dry and put on warm clothing to avoid hypothermia (excessive drop in body temperature).
Wearing the right wetsuit can help avoid these problems.