During a flight as the plane descends we all feel the pressure change on our ears and there are techniques used to equalize this pressure. An old trick of the cabin staff was to give everyone a boiled sweet as this would cause people to regularly swallow which helps to equalize the ears.
In diving as we descend we also have to adapt our bodies to the new environment. Proper equalizing is so important during scuba diving and here we look at how and why.
Water is denser than air. When walking up and down the stairs for example you are highly unlikely to notice any change in pressure, yet when descending in the same 4m while diving you will feel a significant change. A diver must address this pressure to avoid discomfort or even injury in extreme cases.
The lungs are the most important area to equalize as you descend and ascend by any amount of depth. Luckily it is the easiest and most instinctive thing to do and all you need to do is breathe continously. A nice easy breathing pattern is what you should have while diving and this natural response is all you have to do to protect your lungs. That's why the biggest rule in diving is to never, never hold your breathe !
Another important area that we need to protect while descending are the ears and sinuses, this requires the most used equalization techniques. A diver should equalize early and often as they begin an ascent especially during the first 10m of depth where the largest pressure change is. Equalizing should take place every foot or so and no more than every metre and this becomes more instinctive and natural with practise.
There are 3 main techniques to equalize your ears. Blowing through a pinched nostril gently is the most common method. This adds air to the middle ear and assists in the equalizing of the outside pressure. This should be a normal breathe and never a forced blast of air to try and equalize, this can cause an injury. The simple act of swallowing is another method, this redistributes air to equalize the ears as does wriggling your jaw side to side which is the third main technique.
For those using dry suits another type of squeeze can be on the air space within the suit. As a diver descends they need to add air to equalize the suit and then release air during ascent, exactly the same principle applied to the use of a BCD for buoyancy control during a dive. A mask that is on too tight can also cause a squeeze on the air space within the mask while descending. This is felt in the mask area and can be quite severe. To equalize your mask simply blow out through your nose into the mask and try not to have it on too tight next time.
Divers, mainly those new to the sport, can struggle with these techniques to start with which is mainly due to being anxious over descending in general and also bad technique. This eases with experience and before long most divers equalizing just becomes second nature and a lot more natural.
To help divers should try to relax before the dive, take things slowly and ask for help where needed from a dive professional. Never dive with congestion or a cold as this will block sinuses and air migration to the ears that is needed to equalize. Descend in a slow and controlled manner to give you time to equalize regularly and without quick pressure change. Remember to equalize early and often keeping hold of the BCD inflator hose in one hand and keeping the other free to equalize on the way down.
Another thing that all divers are taught is that if you cannot equalize and discomfort is felt to stop the descent immediately, ascend slightly to alleviate the pressure and then equalize. Once successful then the descent can continue. An unequalized ear or sinus can cause injury if you continue to descend further.
Although you should learn and be taught how to take care of your air spaces while diving sometimes this information can be forgotten or not thoroughly understood for some reason. Using these simple techniques and tips will ensure easy equalizing and successful dives time after time.