Can Everyone Dive?
Everyone and everyone should take up diving as a recreational activity – that seems to be the general consensus of die-hard sport divers.
But more importantly, is everyone and everyone fit to dive?
Diving is an exciting recreation, and like all other activities, has its own set of health risks. When someone exclaims that diving is dangerous, it is because the underwater environment is not made for our existence. However, the risk can be minimised by safe practices and ensuring that our health does not jeopardise personal safety, as well as the safety of one’s fellow divers.
Why do we need fitness to dive?
Certification of fitness to dive is necessary for the following reasons:
- To identify underlying medical conditions or risk factors that may be a risk to self or others during diving
- To determine whether measures can be taken to minimise that risk
- To determine whether the diver can take up diving / continue to dive; should not attempt to dive permanently or until a particular medical condition is resolved
Sometimes, the diving insurance company may require you to undergo a medical examination to ascertain the health risk to work out the premium involved.
For professional divers, certification is necessary as part of legislative requirements. There is no legislation affecting recreational diving.
For medical practitioners, the process of certification also provides opportunities to educate the candidate about the risks of diving, and for the candidate to clarify his queries and concerns about dive safety.
How often should a diver be certified fit?
There is really no hard and fast rule as recreational diving is not governed by legislation. It is also advised that all new divers should have a full medical before being allowed to dive in open water.
If you are diving regularly, then the following is recommended:
- Annual recertification
- When planning a dive, but is presently not feeling well or as fit as one should be
- After a diving-related medical condition like decompression illness, barotrauma
- After a severe illness which has required hospitalisation especially if the illness has affected the lungs or ability to handle the rigors of diving (equalise pressure, managing the heavy diving equipment)
Am I fit to dive if I don’t have any medical condition?
In general, one should be fit to dive if he does not have any medical conditions during physical examination. However, he may have certain risk factors that may predispose to diving-related conditions. For instance, someone who has a previous history of decompression illness puts him at higher risk of sustaining decompression illness and may have to adopt a safer diving profile.
It would be best to seek medical advice, especially from a trained diving physician if you have any medical conditions of concern before you begin the open water dive training.
Is fitness to dive standards the same for all divers?
No, the dive standards will vary if you intend to do diving as a recreation or as a profession. It may also be different with the nature of dive – do you intend to do SCUBA diving with air, or would you want to do NITROX diving (with alternative mixes of nitrogen and oxygen). In general, more stringent standards are applied to persons attempting to do more risky dives.
How is Boyle’s Law involved in diving?
Without going into too much detail about the anatomy, the ear and nose can be viewed as air cavities linked to the external environment. Thus as we dive deeper into the water, these cavities would be subjected to increasing environmental pressure as can be seen in the depth gauges.
Pressure increases at a rate of 1 kg/cm2 for every 10m in sea water. Thus we will experience 1 additional atmosphere (1 bar) with every 10m depth of dive.
According to Boyle’s Law, we know that as pressure increases, the volume of the air cavity decreases and conversely, as pressure decreases, the volume increases.
Thus to ensure that the body’s air cavities maintain their functional volumes as we descend or ascend, air needs to be added (during descent) and removed (during ascent).
How does the diver maintain air cavities of the nose and ears?
The air cavities of the nose are known as nasal sinuses or sinuses. They are connected to the nasopharynx by tiny passages. The nasopharynx is the main ‘doorway’ to the exterior via the nose or the mouth.
The ear has an air cavity known as the middle ear and is connected to the nasopharynx by a tiny passage known as the Eustachian tube.
The patency of these passages connecting the sinuses and the middle ear is important means of equalising the pressure within them. As we breathe in air through the regulator, the air would then fill up the deficiencies in the air cavities due to increase in pressure and excess air would be removed during decrease in pressure.
The Eustachian tube is normally shut during pressure increases. Hence, divers would normally do certain manoeuvres to open it such as the Valsalva manoeuvre, swallowing or moving the jaw.
What happens when we can’t equalise pressure?
The sinuses and middle ear will suffer damage as tiny blood vessels may be broken and blood will replace the deficient volume to equalise pressure.
In the case of the middle ear, the ear-drum which is a membrane separating the middle ear from the outer ear, may become torn and water may enter the middle ear.
These medical conditions are known as sinus and middle ear barotraumas respectively.
It is also possible to have inner ear barotrauma where there could be a perforation between the inner and middle instead. In this unusual instance, the fluid in the inner ear could leak into the middle ear. The patient would be susceptible to severe deafness and giddiness.
Symptoms and signs of barotrauma
The diver with sinus barotrauma will commonly experience pain over the eye-ridges or cheek-bones. He may also have a nose bleed.
In middle ear barotrauma, there will be pain in the ears on descent which can be resolved by equalisation manoeuvres. The pain could also suddenly stop during perforation of the ear-drum. Thereafter, he will have hearing loss and probably giddiness. There is also a risk of an ear infection.
Can I dive after ear or sinus barotrauma?
One will usually recover with little residual effect after ear or sinus barotrauma, and usually should be able to be certified fit to dive. However, if there are still problems of auto-inflation, giddy spells and loss of hearing, then that could mean not diving till the symptoms are resolved.
Should I wear ear plugs during diving?
Wearing ear plugs would only create another air cavity in the outer ear. This cavity would not be able to auto-inflate because there is no passage with the outer environment and predispose to barotrauma.
Can I dive if I am already deaf in one ear?
Certainly you can take up recreational diving, but you must be aware of the risks to the remaining ear. Diving can cause damage to the ear in the following ways:
- Barotrauma of the middle or inner ear
- Decompression illness of the inner ear
It would be a terrible disaster if the remaining good ear is damaged during a dive!
Fitness to dive guidelines
A diver may not be able to dive if he has the following medical conditions:
- Non-patent Eustachian tube that has been assessed by a medical physician
- Chronic sinusitis that has not resolved
- Chronic allergic rhinitis that has difficulty responding to anti-histamines
- Active ear infection
- Perforated ear-drum
- Active upper respiratory tract infection such as influenza
What will the doctor look out for when he is examining me?
The doctor will ask for history of ear and sinus infections.
He can evaluate the patency of the Eustachian tube by asking you to do the Valsalva Manoeuvre (i.e. asking you to blow through your nose with your mouth and nostrils closed) and examining the ear-drums using the otoscope. Patency is suggested when he is able to see the ear-drums move with the changes in pressure within the middle ear.
He will also look out for any ear infections such as ear discharge and pain.
Sometimes, the doctor may request for the following investigations:
- Audiogram – to evaluate the level of hearing at the different frequencies. This is useful for compensation purposes should one suffer from barotrauma or any other diving related incident affecting the ears. This is more applicable to professional divers. However, it may also be requested after an incident of ear barotrauma to evaluate progress of recovery.
- Tympanogram – to identify the integrity and function of the ear-drum (tympanum).