Hi SD fans and welcome back to the channel. Decompression sickness is something no diver
ever wants to experience. We’ve been working with the experts at Divers Alert Network for
many years, and here I will give you what they regard as the top five factors that can
increase your risk of ‘the bends’.
Decompression sickness, or 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, or 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, but as we approach the re-opening of more international borders, and you start
planning a dive holiday, let’s review five 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. Interestingly, mild exercise during decompression actually
speeds up off-gassing. 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 the 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.
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.
4. Medical and physical fitness Poor health and physical fitness can compromise
individual safety when diving and may increase risk of DCS. Regular exercise improves fitness
and cardiovascular health, which translates into the ability to cope with emergencies
and mitigates risk of DCS. Adults need two types of regular activity
to maintain or improve their health: aerobic and strength training. The Centres for Disease
Control guidelines recommend:  At least two-and-a-half hours of moderate-intensity
aerobic exercise per week to achieve health benefits, and five hours per week for fitness.
 Muscle-strengthening activities at least two days per week.
5. Breathing gas mixture The breathing gas mixture a diver uses can
play a role in the development of DCS. Enriched air nitrox, also known as simply nitrox, includes
an increased percentage of oxygen and, therefore, a reduced percentage of nitrogen. When diving
nitrox and using the decompression schedule for air diving, the risk of DCS is reduced.
However, the higher oxygen content of nitrox comes with an increased risk of developing
oxygen toxicity if the safe depth limit is exceeded, so watch how deep you go.
This is by no means an exhaustive list. Additional DCS risk factors include state of hydration,
carbon dioxide level in the body, and patent foramen ovale, or PFO.
However, while individual susceptibility to DCS may vary, it is important to stress that
every diver can reduce their risk of decompression sickness by ascending slowly from every dive,
and following recreational diving guidelines.
Have you had decompression sickness? What do you do to reduce your chances of developing
‘the bends’ when diving? Leave your comments below, and remember, if you have any questions
relating to this video or any other topic, fire away – if we can’t answer it, I am
sure someone in our growing community will be able to.
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put the link in the description below. As always, if you are going diving, stay safe!