For scuba divers, avoiding decompression sickness (DCS) should always be a top priority. And by following a few basic rules, you should never have to worry about this potentially dangerous condition.
DCS, also called the bends, is the result of inadequate decompression following a scuba dive. It’s caused by the production of nitrogen bubbles in the circulation, and this is related to the depth and time of a dive, and to the rate at which the diver surfaces from depth.
In some cases, the condition is mild and not an immediate health threat. In other cases, serious injury (and occasionally death) can occur; when this happens, the quicker the relevant treatment begins, the better the chance for a full recovery.
- Use a dive computer
- Safety stop at 5m/15ft
- Stay hydrated
- Maintain a slow ascent rate
- Take part in any exercise and exertion after a dive
- Dive when feeling ill or under the weather
- Miss your safety stop
- Ignore any symptoms if you have been diving
In the old days, divers would pre-plan and “dive the plan”. With the advent of dive computers in the late 1990s, diving has been freed from this rigmarole. A dive computer tracks your dive depth and time during a dive and calculates theoretical nitrogen loading using a decompression model. It displays the time and depth limits you need to stay within to avoid DCS.
The standard safety stop taught to all scuba students is one of the simplest and easiest ways to help avoid DCS. View it very much like a seatbelt.
One of the most common (if not the most common) causes of DCS, especially in the tropics, is dehydration. A simple way to gauge your hydration level is to try to ensure that on every dive you need to urinate. If you go for a 45 minute dive and don’t need to “go” then you are not drinking enough water!
Maintaining a slow ascent rate has become easier to judge nowadays, using that dive computer.
There is strong evidence that exercise immediately after a dive(or indeed during extreme altitude exposures) increases the risk of decompression sickness. In addition, aches and pains can occur as a result of exercise and can be very similar to symptoms of decompression sickness.
These are the reasons for the recommendation not to exercise for four hours after diving. However post-dive exercise is common in the real world, in fact, many of us do it without apparent problems.
So what reasonable recommendations can be made? First, avoid exercise after very long or deep dives. Second, as severe exercise may be more of a problem than mild exercise, avoid heavy exertion after diving. Third, the longer you can wait after diving, the lower the risk becomes, so wait an hour or more.
If you're tired, sick or just not feeling well, just don't dive. Illness and injury increase your risk of decompression illness (DCI), and your performance under water will suffer, too.
A safety stop is a 3 to 5 minute stop made between 15 and 20 feet during the final ascent of a dive. While not strictly necessary, most dive agencies recommend making a safety stop at the end of every dive.
Most DCS happens when the diver has followed all the rules and all the computer guidelines. Even the most experienced divers have been known to ignore the signs of decompression illness – especially if their brains have been affected. Admit it to someone and take the advice given.
Avoiding DCS is relatively easy if you just follow these these few simple guidelines and steps. Many of us have spent years and decades diving without ever suffering any ailments of DCS.