In one of the first articles on my blog we discussed about smoking and its consequences on scuba diving (https://scubadivinggoodpractices.blogspot.com/2020/04/diving-and-smoking.html).
For sure, smoking plays an important role as a risk factor for the development of DCS (decompression sickness). In fact, among other 1000 reasons not to smoke, I recall you that:
- carbon monoxide, as a product of burning, interferes negatively with an efficient gas exchange, thus impeding proper oxygenation of the tissues.
- Nicotine as a vasoconstrictor reduces the blood perfusion in the body extremities, slowing down the inert gas discharge.
- Toxins in the cigarettes damage the alveoli, thus reducing pulmonary functionality and leading to hypoventilation.
What are the other DCS risk factors?
Many of them are environmental (external), others are physiological (internal), but some of them for sure can be reduced by a healthy lifestyle and an average level of fitness! Let us have a closer look.
ENVIRONMENTAL (EXTERNAL) FACTORS
Altitude: dive table and computer are set up for use at sea level. Nevertheless, as you may know, altitude change leads to a variation in compression and decompression ratios, so prior to dive at altitudes different to sea level, make sure that your dive computer is correctly set up!
Water temperature: from a merely physics point of view, there is no doubt that tissue temperature can influence the gas absorption rate. In fact, lower temperature facilitate N2 absorption. However, as a matter of fact, minor body temperature variations as a consequence of diving in cold water do not seem to have significant effect on the gas absorption rate. The most relevant effect of temperature on diving physiology is rather vasoconstriction and the subsequent minor blood perfusion of the body extremities.
Surface intervals and off-gasing: see my previous post “off-gasing and minimum surface interval" (https://scubadivinggoodpractices.blogspot.com/2020/05/off-gasing-minimum-surface-interval.html)
Reverse profiles: also on this topic I already collected some relevant information in the previous post "Reverse profiles in recreational diving" (https://scubadivinggoodpractices.blogspot.com/2020/12/reverse-profiles-in-recreational-diving.html)
PHYSIOLOGICAL (INTERNAL) FACTORS
Gender: although many studies have been carried out on this topics, there is no concrete evidence that gender influences the incidence of DCS.
Age: aging itself does not play a specific role in DCS susceptibility, nevertheless by aging the cardio-vascular system tends to be less efficient, thus slowing down the gas exchange process.
Fitness and exercise: there is no doubt that an average level of fitness and physical activity carried out up to 20 to 12 hours prior to the dive has a positive effect on DCS prevention, by improving cardiovascular functionality. Nevertheless exercise carried out right before of after the dive affects blood circulation, contributing to the increase of micronuclei and tribonucleation due to blood turbulence and thus leading to a greater risk of bubble formation.
Previous injuries, illness and drugs: previous healed injuries may produce local circulation anomalies, affecting inert gas elimination from the involved body part. Also illness and the connected drug consumption may affect body circulation. Moreover empirical observations suggest that if bends occur in one part of the body, they are more likely to appear again in the same region.
Obesity: there are lots of scientific and empirical evidence for obesity as a predisposing DCS factor. This is due to the fact that N2 is more soluble in fat than other body tissues. No need to say that obesity, such as smoking, has other negative long-term implications such as heart disease, high blood pressure, diabetes and others.
Alcohol consumption: there is no doubt that dinking alcohol before a dive should be strictly forbidden! But drinking alcohol should be avoided also in the evening prior the dive and following the dive, as alcohol tends to accelerate circulation and dilate capillaries leading to unpredictable changes of inert gas absorbtion / release. Alcohol also has diuretic properties that could lead to dehydration.
Hypovolemia / Dehydration: hypovolemia can be explained as volume reduction of the blood circulating in the body. This condition is normally caused by dehydration due to many different factors such as alcohol consumption, perspiration, diarrhea or vomit. Easy to understand, a reduction of circulating blood volume results in a less efficient gas exchange process.
Personally, I try to reduce the impact of internal DCS risk factors by avoiding alcohol and cigarettes (as long as I manage, I am not a saint you know š), following a healthy diet and moderate exercise.
And you? How are you getting fit for diving?
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