Anonymous asked in HealthDiseases & ConditionsRespiratory Diseases · 1 decade ago

Health and safety risks for deep sea diving?

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  • 1 decade ago
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    health risks

    Particular problems associated with deep dives

    Deep diving obviously has more consequences and dangers than basic open water diving. Nitrogen narcosis, or the “narks” or “rapture of the deep”, starts with feelings of euphoria and over-confidence but then lead to numbness and memory impairment similar to alcohol intoxication. Decompression sickness, or the “bends”, is when the gas bubbles of nitrogen get caught in the joints on an ascent. Yet, the effects tend to be delayed until reaching the surface. Bone degeneration (dysbaric osteonecrosis) is caused by the bubbles forming inside the bones; most commonly the upper arm and the thighs. Air embolism causes loss of consciousness and speech and visual problems. This tends to be life threatening, but sometimes the symptoms resolve before the recompression chamber are needed. All these are harms and possibly worse effects of deep diving. These physical and physiological stresses require good physical conditioning.

    High breathing gas consumption. Gas consumption is proportional to pressure - so at 50 metres / 165 feet (6 bar) a diver breathes 6 times as much as on the surface (1 bar). Heavy physical exertion causes even more gas to be breathed.

    Increased nitrogen narcosis. This causes stress and inefficient thinking in the diver. When breathing air many divers find 40 metres / 130 feet a safe maximum depth.

    The need to do decompression stops increases with depth. A diver at 6 metres may be able to dive for many hours without needing to do decompression stops. At depths greater than 40 metres / 130 feet, a diver may have only a few minutes at the deepest part of the dive before decompression stops are needed. In the event of an emergency the diver cannot make an immediate ascent to the surface without risking decompression sickness. The diver needs a disciplined approach to planning and conducting dives and needs to carry extra gas for the decompression stops to reduce the risk of being unable to complete the stops.

    Drifting. If long decompression stops are carried out in a tidal current, the divers may drift away from their boat cover or a safe exit point on the shore.

    Increased breathing effort. Gas becomes denser and the effort required to breathe increases with depth (work of breathing).

    Increasing risk of carbon dioxide poisoning.

    Oxygen toxicity.

    High pressure nervous syndrome.

    Dealing with depth

    Carry larger volumes of breathing gas to compensate for the increased gas consumption and decompression stops.

    Rebreathers are much more efficient consumers of gas than open circuit scuba.

    Use helium-based breathing gases such as trimix to reduce nitrogen narcosis and stay beyond the limits of oxygen toxicity.

    A diving shot, a decompression trapeze or a decompression buoy can help divers return to their surface safety cover at the end of a dive.

    Ultra-deep diving

    Amongst technical divers, there are certain elite divers who participate in ultra-deep diving on SCUBA (using closed circuit rebreathers and heliox) below 660 feet/200 metres. Ultra-deep diving requires extraordinarily high levels of training, experience, fitness and surface support. Only eight (or possibly nine) persons are known to have ever dived below a depth of 800 feet on self contained breathing apparatus recreationally.That is fewer than the number of people who have walked on the surface of the moon. The Holy Grail of deep diving was the 1000 ft. mark, first achieved by John Bennett in 2001, and has only been achieved twice since.

    Verified dives below 800 feet Name Location Depth Year

    Nuno Gomes Red Sea

    Red Sea

    South Africa

    South Africa 1,056 feet

    890 feet

    927 feet

    826 feet 2005




    Pascal Bernabé Mediterranean

    Mediterranean 1,083 feet

    873 feet 2005


    David Shaw[nb 6] South Africa 888 feet 2004

    G.M de Oliveira Brazil 898 feet 2002

    John Bennett[nb 6] Philippines

    Philippines 1,010 feet

    833 feet 2001


    Jim Bowden Mexico

    Mexico 925 feet

    825 feet 1994


    Sheck Exley[nb 6] South Africa

    Mexico 863 feet

    867 feet 1993


    Don Shirley South Africa 820 feet 2005

    In 2003 Mark Ellyatt is believed to have dived to a depth of 1,032 feet, but that dive has not been independently verified.

    See also

    Decompression sickness

    Breathing gas



    High pressure nervous syndrome

    Oxygen toxicity



    Safety Rules For Scuba Diving

    Study The Area

    Some areas of the ocean may prove to be unfavorable for scuba diving. Therefore, it is vital to know what the safe places for the sport are. Enquire about the types of sea life present in the area and the safety zones. Check the intensity of the underwater current as well. It is safe to dive into the sea only if the current is not too strong.

    Consult A Doctor

    Get your level of fitness thoroughly examined by a doctor. It is a good idea to get the blood pressure and cholesterol levels checked. Visiting an ENT specialist i

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