| Getting decompression sickness while scuba diving is | | | | floats. While the time spent at each stop varies with |
| not an enjoyable experience. Decompression sickness | | | | the specific nature of each dive, on average, he must |
| was encountered when Brooklyn Bridge was being | | | | stop for anywhere between one and three minutes |
| built. DCS affected the workers on the Brooklyn | | | | every 9 m (30 feet) while coming up. |
| Bridge site who had to spend many hours near the | | | | Scuba divers who take a short dive can safely |
| bridge supports in compressed-air filled chambers | | | | ascend continuously. The thing to remember is that for |
| (caissons) underwater. Upon surfacing, they suffered | | | | any dive deeper than 20 feet; do not rise quicker than |
| from abdominal cramps, joint pain, and in some cases | | | | about 9 m (30 feet) per minute. For extra safety, stop |
| death. | | | | at 10 to 20 feet in any case instead of rising |
| Let's try and understand what causes decompression | | | | continuously. |
| sickness while scuba diving. As the diver descends, he | | | | More stops of longer duration will of course be |
| breathes in the nitrogen in the air through the tank. This | | | | required in case of deeper dives. The factors that will |
| nitrogen dissolves in the blood. While the diver is | | | | influence the number of stops and their duration include |
| ascending, the lowered pressure causes the nitrogen | | | | the time spent at one depth, the diver's general health, |
| to come out of the blood, forming small bubbles. To | | | | body type and age, the temperature during the dive |
| prevent these bubbles from becoming bigger, they | | | | etc. Body type makes a difference as nitrogen is |
| need to be either re-absorbed into the blood stream or | | | | stored more effectively by fat. |
| exhaled out through the lungs. | | | | The mix of oxygen, nitrogen and helium contained in |
| Decompression sickness is the result of a certain | | | | the tank air also affects the number of stops and |
| volume of these bubbles being formed. | | | | allowable rate of ascent. A dive computer which is like |
| A physics principle called Henry's Law can explain this | | | | a small wristwatch calculates all these complex |
| phenomenon technically. All basic diving courses teach | | | | factors to determine a safe rate of ascent and length |
| this law to new scuba divers. What happens when a | | | | of stops for the diver. |
| soda can is popped? Dissolved gases get released | | | | Since a dive computer gives an exact calculation, it is |
| quickly out of the bottle as bubbles due to the quick | | | | safer and more useful than mere experience or using |
| pressure change. Similarly, each point of the dive | | | | tables printed on plastic-laminated cards. However, |
| determines how much gas is dissolved, and how | | | | some divers continue to use these old methods. |
| quickly it will be released while ascending. | | | | The shortcoming of dive tables is the assumption of a |
| Decompression sickness is no laughing matter and all | | | | 'square dive'. That is they assume the diver descends |
| scuba divers are taught how to avoid it. Even if the | | | | straight down and remains at one constant depth |
| diver survives, he can suffer permanent health | | | | before starting to ascend. This makes dive tables only |
| damage. A scuba diver can avoid DCS by using a | | | | partially reliable. |
| dive computer or a diving watch or dive tables. | | | | Given the grave dangers of Decompression sickness, |
| While ascending, the scuba diver should spend time | | | | scuba divers should invest in a good dive computer |
| being neutrally buoyant at certain levels on the way up. | | | | and dive safely. |
| Neutral buoyancy means the diver neither sinks nor | | | | |