DIVERS ALERT NETWORK: ASIA-PACIFIC
Divers Alert Network, widely known as DAN, is an international non-profit medical and research organisation dedicated to the safety and health of divers. WWW.DANAP.ORG
TOP 5 FACTORS THAT INCREASE
YOUR RISK OF ‘THE BENDS’ The experts at Divers Alert Network explain the top five factors that can increase your chances of getting a case of decompression sickness, or DCS
‘T
he bends’, also known as decompression sickness (DCS), occurs when nitrogen bubbles form in the blood, often causing severe joint pain. The common name ‘the bends’ comes from an affected person doubling (bending) over due to the intense pain of the condition. Ascending too quickly and not following recreational diving guidelines are two main causes of decompression sickness. As we approach the re-opening of international borders, and you start planning a dive holiday, let’s review other factors that may contribute to individual susceptibility to DCS.
1. Exertion
The timing and intensity of exercise (also known as workload) during a dive can substantially affect a diver’s risk of DCS. Exertion increases blood flow and its gas-carrying capacity. Consequently, exertion during descent and the deepest phase of a dive increases the amount of gas dissolved in tissues and the subsequent decompression stress. Mild exercise during decompression speeds up offgassing. Exertion immediately following a dive can stimulate bubble formation and increase the likelihood of bubbles passing through the lungs without being filtered out of the circulation. When possible, keep exertion to a minimum during the deepest part of a dive. After diving, avoid exercise as long as possible. If exertion is unavoidable, dive conservatively to minimize risk.
2. Thermal stress
A diver’s body temperature can influence decompression risk. A warmer body absorbs more inert gas and releases it more readily. Conversely, a cooler body absorbs less gas during descent and releases less during ascent. Divers using protective suits without active heating should avoid long exposure that may chill them toward the end of the dive. When using heated garments, a diver should stay comfortably cool at depth and warm during decompression. Staying comfortably warm during decompression and after dive promotes inert gas elimination and reduces the risk of DCS. However, attempt to quickly rewarm after dive, like taking hot shower or bath, may provoke decompression illness.
38
3. Post-dive air travel
Flying after diving increases decompression stress because the pressure in an aircraft cabin is lower than atmospheric pressure on the ground. The recommended guidelines for flying after diving are as follows: • After a single no-decompression dive, a minimum preflight surface interval of 12 hours is suggested. • After multiple dives per day, or multiple days of diving, a minimum preflight surface interval of 18 hours is suggested. • After dives requiring decompression stops, a pre-flight surface interval substantially longer than 24 hours is considered prudent. Adhering to the guidelines above can reduce your risk, but offers no guarantee against DCS. Observing surface intervals longer than the recommended minimums helps to further reduce a diver’s risk.
WWW.SCUBADIVERMAG.COM.AU
