## Absolute Pressure Scuba Diving
### Introduction
In scuba diving, absolute pressure refers to the total pressure exerted on a diver’s body by the surrounding water. It includes both atmospheric pressure and the pressure exerted by the weight of the water column above the diver. Absolute pressure is important to understand for divers because it affects the solubility of gases in the body and can lead to decompression sickness (DCS) if not managed properly.
### Atmospheric Pressure
Atmospheric pressure is the weight of the air column above the Earth’s surface. At sea level, atmospheric pressure is approximately 14.7 pounds per square inch (psi) or 1 atmosphere (atm). As you descend in the water, the atmospheric pressure decreases by approximately 1 atm for every 33 feet (10 meters) of depth.
### Water Pressure
Water pressure is the weight of the water column above a diver. The deeper a diver descends, the greater the water pressure becomes. Water pressure increases by approximately 0.445 psi for every foot (0.3 meters) of depth.
### Absolute Pressure
Absolute pressure is the sum of atmospheric pressure and water pressure. At sea level, absolute pressure is equal to atmospheric pressure (1 atm). As you descend in the water, absolute pressure increases due to the increasing water pressure. For example, at a depth of 33 feet (10 meters), the absolute pressure is 2 atm (1 atm of atmospheric pressure + 1 atm of water pressure).
### Effects of Absolute Pressure on the Body
Absolute pressure affects the solubility of gases in the body. As absolute pressure increases, the solubility of gases in the blood and tissues also increases. This can lead to the formation of gas bubbles in the body if the pressure is reduced too quickly. DCS occurs when these gas bubbles block blood vessels and cause tissue damage.
### Managing Absolute Pressure
Divers can manage absolute pressure by controlling their depth and ascent rate. The deeper a diver descends, the greater the absolute pressure becomes. Divers should ascend slowly to allow the gases in their body to dissolve slowly and safely. The recommended ascent rate is no more than 30 feet (9 meters) per minute.
### Diving Tables and Computers
Diving tables and computers are used to calculate safe ascent rates based on the diver’s depth and time spent at that depth. Divers should use these tools to help them manage absolute pressure and avoid DCS.
### Conclusion
Absolute pressure is an important concept for divers to understand. By controlling their depth and ascent rate, divers can manage absolute pressure and avoid DCS. Diving tables and computers are valuable tools that can help divers stay safe while enjoying their dives.
### Additional Information
**Factors that Affect Absolute Pressure:**
* Depth
* Atmospheric pressure
* Water density
* Gravity
**Symptoms of DCS:**
* Joint pain
* Muscle weakness
* Skin rashes
* Headache
* Fatigue
* Nausea
* Vomiting
* Seizures
* Unconsciousness
**Treatment for DCS:**
* Hyperbaric oxygen therapy
* Recompression chamber
* Rest