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Scuba Diving
Ah Yin and Chung Chai arranged to travel together to the Maldives for scuba diving in emerald waters under the sheltering blue sky. Although both of them knew how to swim, they had never been trained in scuba diving before. When they learn that such training will be provided at the destination, with a coach to escort them underwater, they felt immensely relieved. Looking forward to their vacation, they had not the slightest doubt whether they were physically fit enough for scuba diving. Rather, their minds had long drifted to the destination, as they imagined themselves to be kissing the fishes and touching the corals under the sea. On the eve of their departures, news reached them about a mishap involving veteran divers, who perished in the deep. Only then did they become alerted to the dangers. They started to wonder how scuba diving would affect them physically and whether they were suited for this pursuit.
- Scuba diving is not a high-risk activity with adequate training
- Pre-dive equipment inspection and an avoidance of substance intake are necessary
- Staying calm is important and do not come out of the water in a hurry
- Several illnesses caused by water pressure during scuba diving
- Admire the beautiful water creatures with eyes not hands
- High water pressure at the ocean's depth is demanding on the diver's physique
- Boarding a plane immediately can lead to maladjustments to air pressure differences
- Scuba diving is unsuitable for small children and pregnant women
Source: Dr. Willis W. H. Kwok, Specialist in Emergency Medicine
Scuba diving is not a high-risk activity with adequate training
Any sport activity come with inherent risks and it is not true that scuba diving is particularly perilous. The features of scuba diving, as a sport, include: Being immersed in an unfamiliar underwater environment, with a need for the equipment to be in place, along with a mastery of diving techniques. It is therefore necessary for participants to receive certified training. Generally, scuba diving training features three phases. The first of them will comprise theory lessons. This is followed by training in the safety of a swimming pool, where the water currents are more stable. And when the trainees become skilled in the techniques would the training be carried out in the open sea. Upon completing the course with a grasp of the techniques, the trainees would be offered a diving license. With this and an awareness of safety, they could now enjoy the pleasures of scuba diving.
Pre-dive equipment inspection and an avoidance of substance intake are necessary
Before getting in the water, there are a few things to be noted, especially for beginners:
| 1. | Be equipped for scuba diving. Some of the gear should be prepared by the divers themselves. But the heavier apparatuses such as oxygen tanks and weights can be rented. Before getting in the water, check carefully whether you are thoroughly geared, especially the rented equipment. |
| 2. | Wear a diving suit to keep yourself warm, first of all. Otherwise, within ten minutes underwater, you'll start feeling cold. Secondly, it will help prevent exposure of your skin to water for a long period of time, which will reduce the likelihood of you being scratched by undersea objects. What is more, diving suit fabric also helps improve your buoyancy. |
| 3. | Be mentally prepared and alerted. Be cautious. |
| 4. | Before getting under water, beginners should inform organizers of the scuba diving activity for the latter to keep a watchful eye on them |
| 5. | Scuba divers are advised to pair up with a partner under a "Buddy System", where they could look after each other. Especially for those scuba diving for the first few times, it is best for them to pair up with more experienced divers. This is because, without the presence of a coach, they could count on someone experienced for help should they run into problems. A "Buddy System" should be adopted for those who travel overseas for scuba diving. |
| 6. | Overeating and starvation before a scuba diving session should be avoided |
| 7. | Stay alert during the scuba diving process. Certain kinds of food or substances can affect one's consciousness, such as alcohol, sleeping pills, tranquilizers, which can lead to decreased levels of consciousness, difficulties in concentration and an inability in making accurate judgments. Those who have consumed these substances should stay out of the waters. If the participants are under medical treatment, they need to assess how they will be affected by their medications they take and a doctor should be consulted in this case. Some people may be prone to palpitations after drinking coffee and tea, so they should avoid these beverages before engaging in scuba diving. |
Staying calm is important and do not come out of the water in a hurry
In the unfamiliar undersea environment, it is easy for anyone to become panicky and staying calm is important. Through the automatic adjustments of the gear they are equipped with, scuba divers inhale appropriate amounts of air from their oxygen tanks. But sometimes, when breathing becomes constricted, some of them react with so much anxiety that they break loose of their breathing apparatuses in their physical struggles, causing them to gasp for air.
The undersea is an alien environment where in time of contingencies, some divers become so panicky that their reflexes bid them to ascend back to the water surface at a high speed. Yet ascending back to the water surface in a short period of time is very dangerous and "air pressure injury" might occur. The pressurized air inhaled will inflate during elevation and organs filled with air will be pressed, thus crushing the nasal cavities or worse still, crushing the lung ("collapsed lung"). It may also lead to air residing round the heart and subcutaneous fat. Hence, one should not come out of the water in a hurry nor should they hold their breaths as they surface. Rather, they should breath when their gradually emerge from the water.
Examine the conditions on the sea surface while ascending as boats might pass by occasionally. In the bay area, high-speed rides such as the banana boat ride may be frequent. Collision with these vessels might lead to grave injuries.
Several illnesses caused by water pressure during scuba diving
The undersea air pressure is high and diving illnesses might occur if prolonged or deep diving is followed by improper handlings:
1. Decompression illness
Scuba divers inhale compressed air from gas tanks which contains mostly nitrogen (~79%), oxygen (~21%), trace amount of carbon dioxide and inert gases. Within these, oxygen is consumed for respiration. In a prolonged diving at depth, large amount of nitrogen is dissolved in the body. It froths as small bubbles if a diver ascending too fast from water and results in "decompression sickness".
Traditionally, there are two types of "decompression sickness":
Type 1: Itchiness and rashes on skin. Acute pains on joints especially shoulders, elbows and hands;
Type 2: In a more serious condition, pulmonary, cardiovascular and neurological systems are damaged. Signs and symptoms include pains around the lower chest and the back or shock. The spine may be damaged if weakness and numbness are experienced in leg muscles.
In recent years, some authorities refer the term "decompression illness" to include decompression sickness and arterial gases embolism (mention below), as they share the same causes and managements are similar.
2. Arterial gas embolism
When ascending at a high speed, air expands and circulates the body in the form of froth, which may block blood vessels and cause serious problems. Strokes may occur if froths lodge in the cerebral blood vessels. If embolisms occur in coronary arteries, heart attacks may result.
Always have a dive plan before going into water. Dive according to the predetermined plan and never go beyond the no-decompression limit. If decompression sickness and arterial gas embolism occur, treatment at the decompression chamber is needed. Froths reside inside body tissues can be dissolved out slowly through pressure adjustment. In Hong Kong, there is a compression chamber run by the Hong Kong Fire Services Department on Stonecutter Island. Similar facilities can also be found at the privately-funded Hong Kong Diving Medicine & Hyperbaric Medicine Centre.
3. Nitrogen narcosis
There is a danger of nitrogen narcosis when conducting deep scuba diving. The pressurized gas inhaled by scuba divers is consisted of 79% nitrogen. Deep diving at 30 meters or more below the sea level will see the increase of nitrogen pressure which subjects scuba diver to a similar state as intoxication or trance results in nitrous oxide (laughing gas) inhalation. Such drowsiness will cause certain dangers. However, it can be recovered once ascend back to shallower level.
Admire the beautiful water creatures with eyes not hands
Scuba diving is an exercise for appreciating the beautiful creatures under the sea. Observe with eyes, feel with heart, memorize with brain or camera. Do not pick up any objects under the sea, do not leave any rubbish behind, and do not touch the sea creatures or the natural environment will be damaged.
Most sea creatures are not harmful and will not attack humans unless they perceive as being offended by human actions. The most common harms done by sea creatures are being stung by venomous stings or got bitten.
Dangerous sea creatures with attractive appearances include Portuguese man-of-war jelly fish, sea snail, stone fish, stingray, eel and sea urchin, etc. Remember to observe with eyes but not hands in order to enjoy the true fun of scuba diving.
High water pressure at the ocean's depth is demanding on the diver's physique
Due to its high water pressure, the bottom of the sea is markedly different from the water surface or the land, environmentally, and this places a certain strain on the diver's physique.
| 1. | As a sport, scuba diving is rather enervating and divers should find out whether they can cope physically. |
| 2. | Those who suffer from certain illnesses would be at risk of "decompression sickness", or that their lungs would be damaged as a result of exposure to a high-pressure environment. Those inflicted with conditions commonly known as a "pneumothorax" or "burst lung" should stay away from scuba diving. |
| 3. | Some diseases can compromise the patient's levels of consciousness and even their physical mobility, such as diabetes, epilepsy, cardiac irregularities and heart disease. Patients with such diseases are unsuitable for scuba diving. |
Boarding a plane immediately can lead to maladjustments to air pressure differences
Generally aircraft cabins are pressurized to attain 80% of the atmospheric pressure at sea level. Emerging from the high-pressure undersea environment to the water surface, scuba divers who board a plane that ascend to great altitudes within a short period of time may be prone to decompression sickness. For those involved in a once-off scuba diving session, where it is not necessary for them to undergo any routine to help them adjust to water pressure differences undersea, it is advisable for them to board a plane only after a 12-hour lapse. If they were involved in scuba diving activities several times a day or over several days, then such a lapse should be extended to at least 18 hours. If the scuba divers were required to follow procedures to adjust physically to pressure differences underwater, they would need a break of over 18 hours before catching a flight. Yet such procedures do not guarantee a total elimination of decompression sickness. All in all, the longer the break, the less likely they would suffer decompression sickness.
A similar scenario awaits those who engage in mountaineering following a scuba diving session; the only difference is that a mountain's altitude is lower compared to that of an aircraft high up in the sky. However, for those on a vacation where both activities are involved, they are best advised to have their mountain trekking activities scheduled ahead of the scuba diving sessions.
Scuba diving is unsuitable for small children and pregnant women
There are no upper age limits in scuba diving. Anybody can engage in the sports so long as they are physically fit. But it must be noted that one's physical fitness declines with age and the elderly are at a greater risk of having chronic diseases such as cardiac or lung problems. So, they need to undergo a comprehensive medical examination before a scuba diving session.
Some scuba diving clubs allow children as little as eight years old to dive. However, it is more appropriate to learn scuba diving in one's teenage years. For, at this age, one will be better able to meet the challenges of scuba diving, whether in terms of physical fitness or judgment ability. Presently, there are no research studies that show that exposure to a high-pressure environment will affect fetal growth, but generally, medical doctors would advise pregnant women to engage in scuba diving.
Source: Dr. Willis W. H. Kwok, Specialist in Emergency Medicine
