Deep diving has limits
All divers have all tried to reach the limits of recreational diving with air gas. Yes, all have tried at least once. From my experience, I have already met some intro divers who have reached 30 meters, Open Water Junior divers dive at 40 meters, and some “experienced” divers who tell me about their adventures over 60 meters.
The risks are invisible
This is not because the risks are invisible they do not exist. The risk of decompression sickness have increased, the risk of running out of air is growing, the nitrogen narcosis tends to increase gradually as you go deeper. But these risks are manageable and can be anticipated with proper training, proper diving equipment and a good attitude.
As the ambient pressure increase at great depth, the risks of decompression sickness increases too. This can be avoided by properly planning the dive using the dive tables or a dive computer. Respect your dive plan, keep a slow but steady ascent speed, and even if you do not have a decompression stop to do, do the safety stop. Observe a longer surface interval before the next dive.
Air consumption increases along with the depth. The more you go deeper, you will consume. To remedy this problem, it is important to take with you the amount of gas needed to dive and ensure the ascent part. Observe your air gauge more regularly. For divers who have high air consumption, you can carry a Pony tank which provide you additional gas, or use larger tanks (15L or 18l) and why not bi-cylinders.
With depth, the partial pressure of nitrogen also increases. The first signs of narcosis appear with PpN2 of 3.20 bar or 30 meters. With PpN2 5.6 bar (60 meters), everyone is narked. We do not all react in the same way facing the narcosis. The first signs describe tingling in the extremities of the body, a sensation of euphoria, slower reactions. Narcosis can become more severe and cause dizziness, disorientation or even a blackout. The nitrogen narcosis do not pose health problem in the long term, simply return to the area of 20 meters all symptoms will disappear. To anticipate the narcosis, it is important to know your personal limits, descent procedures with a buddy, and know when to stop diving when signs become too strong.
The available training courses
To practice deep diving, there are several courses for divers. PADI Advanced Open Water certification allows to reach a depth of 30 meters. To achieve the maximum depth of recreational diving, PADI Deep Diver specialty allows you to reach 40 meters. Beyond 40 meters, you should consider technical diving courses such as Tec Deep Diver specialty (up to 50 meters) or Tec Trimix Diver (up to 120 meters).