Sight Search

Loss of Consciousness

When diving, it is essential to prevent the loss of consciousness underwater at all costs. Learn what causes to look out for in order to manage and minimise the risk of incapacitation.
 
Humans are not designed for living underwater. Diving is, and remains, a very unnatural activity. The only way to engage in, and return safely from, prolonged submersion is by learning and following certain procedures and by mastering the use of relatively complex equipment. All this requires mental alertness and agility in order to adapt to a hostile, alien environment; the physical ability to react quickly and appropriately to potentially life-threatening emergencies; and training to guide the process by means of over-rehearsed procedures and effective patterns of action. From the classroom to confined water, and ultimately to the open sea, there is a continuum of learning and response that requires both intelligence and constant situational awareness. This is exemplified by the golden rule which is taught in virtually all diving training programmes: stop, think, breathe, plan and act. To do so, a diver must be in complete control of both body and mind.
It stands to reason, therefore, that any condition that may impair one’s attention, awareness, or the proper evaluation of risk while underwater, let alone consciousness itself, may have catastrophic results and the prospect of death by drowning. One could even say that the loss of consciousness underwater (LOCU) equals death, unless the person is very lucky indeed. This could also apply to situations where effective decision-making is lost, which is a state of functional unconsciousness leading to impulsive, instinctive and ultimately involuntary actions by the diver. This cascade of catastrophe is usually described as panic. Typically, the diver will eventually make a frantic ascent to the surface in search of air. They forget that in scuba diving there is a better, safer solution which is available from their buddy. Unfortunately, this does not always materialise, either due to an irrepressible urge to surface, or due to a buddy system failure. The latter may be the result of separation by physical distance, lack of mutual awareness, or abortive efforts at air-sharing. The net result is a familiar acceleration to the surface where barotrauma, decompression illness (DCI) and death may await them. Of those who reach the surface, many lose consciousness shortly before or after their arrival, only to sink back to the bottom, unwitnessed. Here, they are usually only discovered much later when they are well beyond any hope of recovery.

To illustrate the very real, practical ways in which mental impairment may affect a diver’s safety, listed below are some real-life examples:
  • A diver suffering from petit mal epilepsy, leading to moments of mental absence, performed a dive to 30 m. As a result of an episode of mental absence, the diver omitted several minutes of decompression and made an uncontrolled ascent due to an over-inflated buoyancy compensator, of which he was oblivious at the time. The result was that he suffered serious DCI.
  • Another diver, suffering from diabetes for which he was taking insulin, developed a seizure underwater due to low blood sugar. Miraculously, the diver was rescued and taken to the surface, but because he had not disclosed the fact that he was a diabetic for fear of being precluded from diving, this was not suspected as a cause. The diver was taken to a chamber for presumed DCI and suffered permanent brain damage as a result of his prolonged and uncorrected blood sugar level.
  • A double fatality resulted from a serious case of nitrogen narcosis. Two divers performed an air dive to 66 m. One became completely disorientated and started swimming toward the ocean floor. The other, also presumably affected by nitrogen narcosis, tried to retrieve his buddy. Both lost consciousness and drowned with more than 70 bar left in their scuba diving cylinders.
  • Another fatality occurred recently in a rebreather diver. As a result of a relatively rapid ascent from 90 m, the diver experienced dilution hypoxia at 18 m. The gas he was breathing at depth became unable to sustain his consciousness closer to the surface, and the device was unable to adequately enrich the breathing mixture with oxygen due to an overinflated counter-lung. Hours later, he was discovered dead on the ocean floor. 
These are but some examples to illustrate that loss or even a temporary lapse in consciousness underwater may result in injury or death. Importantly, unlike unconsciousness on land, where we are at least able to continue breathing, water does not afford us the same luxury.
IMPORTANT CAUSES OF THE LOSS OF CONSCIOUSNESS UNDERWATER

Amongst the many possible causes for the LOCU, the following are the most likely and frequent:

H - Hypos and hypers (lows and highs): Hypoglycaemia, hypotension, hypoxia,               hypocarbia, hypercarbia or high pressure nervous syndrome (HPNS);
E - Epilepsy or electrolyte disturbance;
A - Apoplexy (stroke), arrhythmias or animals (hazardous aquatic animal injuries); and
D - DCI, drugs or damage.
Hypos and hypers
  • Hypoglycaemia (low blood sugar) is a possible complication of insufficiently controlled diabetes. Refer to http://www.diversalertnetwork.org/research/projects/diabetes/
  • Hypotension (low blood pressure) can lead to the insufficient circulation and oxygenation of the brain, with sudden LOCU. This is unlikely during immersion as the increased oxygen partial pressure (PO2) in the breathing gas at depth and the anti-gravity effect of immersion usually prevent blood from “going to the feet”. However, a hypotensive individual may suffer from the consequences of low blood pressure when emerging from or leaving the water.
  • Hypoxia (low oxygen concentration or PO2) leads to sudden blackout and can occur during ascent from a deep freedive, due to the malfunction in a rebreather or due to accidental gas switching during technical diving.
  • Hypercarbia (high carbon dioxide [CO2]) may occur with excessive skip-breathing or as a side-effect of insufficient gas exchange at depth due to greater gas density and is possibly combined with nitrogen narcosis. Eventual consequences may include precipitating panic or LOCU.
  • Hypocarbia (low CO2) may be caused by excessive ventilation due to panic and, at its extremes, can lead to the possible LOCU. Hypocarbia is infrequent underwater.
  • HPNS is rare and associated with deep commercial or military diving, but it may also affect the modern extreme recreational technical divers at depths in excess of 150 m. Its extreme results are tremors of the hands, muscle jerking, nausea, vomiting, dizziness, hallucinations, bouts of somnolence and the deterioration of mental and motor performance.
Epilepsy and electrolyte disturbance
  • Epilepsy and seizures in general (due to oxygen toxicity, hypoglycaemia or many other causes) result in the LOCU.
  • Electrolytes refer to the various salts and ions in our blood and body fluids that determine the proper functioning of our cells. Illnesses cause changes in body salts or the electrolytes in the body. Our bodies are particularly vulnerable to changes in sodium, potassium and calcium concentrations, each of which can lead to LOCU situations, frequently complicated by cardiac dysfunction. Diseases, conditions and even medication that may cause changes in electrolyte equilibrium should be carefully considered when assessing fitness to dive.
Apoplexy, arrhythmias and animals
  • Apoplexy is a term that is used to indicate sudden cerebral vascular accidents, such as a stroke, which cause immediate and serious cerebral consequences. Although loss of consciousness during a stroke is relatively rare, it may occur. More commonly, sudden weakness or paralysis from a stroke may jeopardise a diver’s safety. Individuals who are at a high risk for cerebrovascular incidents should seriously consider their fitness to dive. They should also consider the safety implications for their buddies who would be expected to respond to such an emergency.
  • Arrhythmias are alterations of the cardiac rhythm (heart rate). Some may cause unpleasant sensations of a pounding pulse, anxiety and even panic. Occasionally, certain arrhythmias may result in a partial or complete loss of consciousness. Any condition affecting the heart rate or rhythm should be evaluated thoroughly prior to diving. Some slow heart-rate-related arrhythmias are innocent and may actually indicate superior cardiovascular fitness. Such slow heart rates are quite common in highly-trained individuals or runners. However, a family history of sudden cardiac deaths in young individuals should prompt investigations for inherited heart muscle or cardiovascular risk factors. A dramatic slowing down of the heart rate may also occur due to the stimulation of certain areas within the body such as the neck below the angle of the jaw and behind the eyes. Manual pressure or tight-fitting equipment may cause extremely slow heart rates with the LOCU and even cardiac arrest in particularly susceptible individuals (vasovagal reactions). These individuals are normally disqualified from diving.
  • Animal lesions can cause immediate strong pain, fear reaction, panic and even rapid LOCU due to serious trauma (like sharks or stingrays), envenomation (like jellyfishes, sea snakes or stonefishes) or anaphylaxis, which is a severe allergic reaction.
Decompression illness, drugs and damage or trauma
  • DCI, particularly in the form of cerebral gas embolism, can cause loss of consciousness both during ascent and at the surface.
  • Drugs, such as sedatives or recreational drugs, can cause a loss of mental acuity, drowsiness, the enhancement of nitrogen narcosis, and even the LOCU when used during or in close association with diving activities.
  • Damage, referring to physical damage such as head trauma (like bumping the head on the bottom of a boat) even when not immediately causing the LOCU, can precipitate anxiety, panic, loss of control, uncontrolled ascent, pulmonary barotrauma, DCI or drowning.
MINIMISING THE RISK OF LOSS OF CONSCIOUSNESS UNDERWATER

Apart from the obvious causes listed previously, there are many other conditions that may pose a risk of the LOCU. A previous head trauma with loss of consciousness or memory for more than 30 minutes carries a significant risk of epilepsy, even months later. Similar risks are incurred following brain surgery. Even minor head injuries should prompt a delay of six weeks before returning to diving.

Epilepsy is generally considered an absolute contraindication to diving. While underwater, a diver may be exposed to possible triggering stimuli for seizures, including glare, flickering lights, sensory deprivation, hyperventilation and an increased oxygen partial pressure. Having a convulsion underwater often involves breath-holding during the fit, making pulmonary barotrauma a high risk, as well as drowning.

These are some existing recommendations on the subject:
  • British Sub-Aqua Club (BSAC) medical committee: “An epileptic can be permitted to dive after five years free from fits and off medication. Where the fits were exclusively nocturnal, this can be reduced to three years.”
  • Underwater and Hyperbaric Medical Society diving committee: “Individuals with epilepsy, who have been seizure-free for five years and take no medication, who choose to dive should be advised to avoid hyperventilation and cautioned that elevated pressures of oxygen may precipitate seizures. Individuals with controlled epilepsy (taking medication and seizure-free for two years) are advised not to dive.”
Even individuals who may meet these recommendations should bear in mind that they may still be at a significantly high risk for developing seizures. They should advise their buddies to this effect and keep within close contact during diving.

Diabetic divers who are well controlled can usually dive without seriously increased risks. However, they should bear in mind that they remain at risk for hypoglycaemia and therefore the LOCU. Attention should be given to minimising the risk, for example, by eating before diving.

Second only to the loss of consciousness, panic remains the most common cause of diving fatalities. In a review of 12 149 recreational divers by Dr David Colvard consisting of
2 916 females and 9 233 males, he discovered that 57% of the females and 45% of themales who reported an episode of panic underwater had experienced prior episodes of panic on land. He concluded that a history of prior panic corresponded to a two-fold increased relative risk of panic while diving.
MANAGING AN UNCONSCIOUS DIVER & MINIMISING RISKS FOR THE RESCUER

When providing emergency first aid or assistance, always remember that the first attention should go to the safety of the rescuer. It is undesirable to increase the number of victims by adding the rescuer to the list. Yet, the urge to help often blinds rescuers to the dangers and this also becomes a form of functional loss of consciousness. A frequently-ignored factor is the risk of developing DCI. In fact, it is not uncommon to end up treating the rescuer for DCI after a heroic retrieval of their dead buddy from the ocean floor. While contentious in all its aspects, a victim found on the ocean floor after an unwitnessed descent, with the regulator out of the mouth, is likely to be beyond the hope of recovery. In this situation, the victim, if this can be undertaken safely, should probably be allowed to make an independent, buoyant ascent to the surface. Otherwise, the body should be attached to a buoy line or have the air removed from the buoyancy compensator (BC) to limit drifting and thereby improving the chances of recovery during a subsequent search. Clearly, this situation is different to being confronted by a breathing but anxious or incapacitated diver. For the rescuer this then becomes a moral decision. The rescuer will risk their health for the sake of another’s life – risk today or guilt tomorrow. For the victim, the risk of developing DCI is certainly more acceptable than the prospect of death by drowning.

Loss of consciousness, whether real or functional, remains one of the biggest threats to a diver’s safety underwater. It is incumbent upon instructors and dive leaders to be attuned to these risks. They need to be vigilant and wary of those divers who may be particularly susceptible and to identify them in advance and, hopefully, to protect them from harm.

Download Article >

2 Comments


Russ - January 23rd, 2017 at 10:08am

LOCU; I enjoyed reading this article very much. Dr Cronje diplomatically avoided another cause of LOCU, i.e., Stupidity in the case of the diabetic diver, and again in the case of the divers who did an air dive to 66 m (I'm assuming they were recreational divers), which blows the bottom out of all standard dive tables. The individual with diabetes was not mature or considerate enough to realise that he posed a serious threat to other divers in his group; this also makes a good argument for mandatory medical examinations prior to a diving course. With the growing popularity of Free Diving and Spearfishing, I wonder if Dan could promote an article on LOCU specific to these dive activities as well. Thank you

Categories

 2023
immersion and bubble formation 232bar 24Hours AGE AIDA Accident management Accidents Acid reflux Acute ailments Adam Sokolski Advanced courses Rescue diver Aerobic exercise After anaesthesia Aged divers Air Ambulance Air Quality Air consumption Air exchange centre Air hose failure Air supply Airway control Air Alert Diver December 2022 Alert Diver Magazine Alert Diver March 2023 Algorithms Alice Cattaneo Alice Modolo Alopecia Alternate Airsources use Alternater Air Source Alternative gas mix Altitude changes Altitude diving Altitude sickness Aluminium Oxide Ama divers Amino acids Amos Nachoum Anaerobic Metabolism Anilao Animal intelligence Animal life Annual renewal Antarctica Anxiety Apea Apex predators Apnea addicts Apnea Apnoea Aqua corps Aquatic creatures Aquatic life Aquatics and Scuba Diving Archaeology Argonaut octopus Argonauts Argon Arrythmia Arterial Gas Embolisms Arterial gas embolism Arthroscopic surgery Aspirin Audible signals Aurel hygiene Australian Flat backed Australia Aviation o2 BCD BHP BLS BWARF Baacterial infections Back adjustment Back pain Back treatment Backextensors Backmount CCR Badages Bag valve mask Bags Bahamas Bail out cylinder Balancing Bandaids Barbell back squat Barometric pressure Barotrauma Basic Life Support Basslets Batteries Beach entry Beached coral Becky Kaga Schott Becky Kagan Schott Beluga whales Bench press Bends Benign prostate hyperplasia Benzophenones Beth Neale Beyond Standards Big Sur Bilikiki Tours Biophysics Black Water Photography Black Blood flow Blood pressure Blood thinners Blue Desert Blue Wilderness Blue economy Blue heron Bridge Bluff Blurred vision Boat diving Boat etiquette Boat safety Boats Bobbit worm Boesmans gat Boesmansgat Bonaire Bone fractures Bouyancy compensators Bouyancy control device Bouyancy controls Boyle's Law Boyle\'s Law Bradycardia Brain Brandon Cole Breast Cancer Breath Hold Diving Breath hold diver Breath holding Breath hold Breath-hold Breathing Gas Breathing gas contamination Breathing oxygen Breathing Breathold diving Bright Bank Broken bones Bruising Bubble detection Bubbleformation Buddy Exercise Buddy checks Buoyancy Burn wounds Burnshield Burns Business B CCR CE markings CGASA CMAS CNS CO2 COVID-19 Updates COVID-19 COVID CPR CSI Cabin pressure Caissons diseas California Camera equipment Camera settings Cameras Cancer Remission Cancer treatments Cancer Cannabis and diving Cannabis Cape Diver Research Cape Nudibranchs Cape Town Dive Festival Cape Town Dive Sites Cape Town CapeTown Carbon Monoxide Carbon dioxide Cardiac Health Cardiac research Cardiaccompromise Cardio health Cardiological Cardiomyopathy Caribbean Carmel Bay Carribean Conservation Catalina Island Cave Cave diving Cave divers Cave diving Cave exploration Caves Cave Cenotes Ceotes Challenging Environments Chamber Locations Chamber Safety Chamber maintenance Chamber medical staff Chamber science Chamber treatment Chamber Charging batteries Charles' Law Charles\' Law Charles\\\' Law Charles\\\\\\\' Law Charles\\\\\\\\\\\\\\\' Law Charlie Warland Chemotherapy Chest compressions Children diving Chiropractic Chlorophll Chokka Run Christina Mittermeier Chuck Davis Chuuk lagoon Citizen Conservation Citizen sciences Citizen science Clean Air Cleaning products Cleeve Robertson Climate change Closed Circuit Rebreathers Closed Circuit Rebreather Clothing Cmmunity partnership Coastal diving Coastalexcursion Cold Water Cold care Cold sores ColdWater Cold Commercial Fishing Commercial diving Commercial operations Commercial schools Common consideration Common understanding Communication Compact Cameras Composition Compressed Air Compressed gas Compressor operators Compressors Concussion Congestive heart Faiture Consercation Conservation Photographer Conservation photography Conservation Contact lenses Contaminants Contaminated air Coping with cold Coral Bleaching event Coral Conservation Coral Reefs Coral Restoration Coral bleaching Coral preservation CoralGroupers Corals Core strength Corona virus Coro Coservation Costamed Chamber Courtactions Cozumel Cradiac valvular Crime scene Cristina Mittermeier Crohns disease Crowns Crystal build up Crystallizing hoses Cubs Cutaneous decompression Cutting tools Cylinder Ruptures Cylinder capacity Cylinder handwheel Cylinder safety Cylinder valves Cylinder weight Cylinders DAN Courses DAN Europe DAN Profile DAN Researchers DAN hotline service DAN insure DAN medics DAN members DAN report DANTraining DCI DCS Decompressions sickness DCS theories DCS DEMP DM training DNA DPV DReams DSMB Daan verhoeven Dahab Dalton's Law Dalton\'s Law Dalton\\\'s Law Dalton\\\\\\\'s Law Dalton\\\\\\\\\\\\\\\'s Law Danel Wenzel Dangerous Marinelife Dauin island Dave McCowan David Doubilet Dean's Blue Hole Dean\'s Blue Hole Deco dives Decompression Illness Decompression Sickness Decompression Stress Decompression benenfits Decompression chamber Decompression illsnes Decompression ilness Decompression limits Decompression treatment Decompression Decomression sickness Decorator crabs Deep Freediving Deep diving Deep water exploration Deepest SCUBA Dive Delayed Offgassing Dennis Guichard Dental Depth limits Dever Health Diadema Response Team Diagnosis Diaphragms Diets Diopter Dirty water Discomfort Diseases Disinfection Disorientation Distraction Dive Accident Dive Action Dive Buddy Dive Chamber Dive Chmber Dive Computer Dive Destinations Dive Destination Dive Fitness # fit to dive @Dive health Dive H Dive Industry Dive Instruction Dive Instructor Dive Lights Dive Masters Dive Medical Form Dive Medical Dive Practices Dive Professionals Dive Pros Dive Rescue Dive Research Dive Safari Dive Safety Tips Dive South Africa Dive Taiwan Dive Training Dive Travel Wakatobi Dive Travel Dive accidents Dive bell Dive buddies Dive caves Dive centre rules Dive communications Dive computers Dive courses Dive cover Dive cylinder Aluminium Dive equipment Dive excursions Dive exercise Dive exeriences Dive experience Dive fitness Dive gear Dive heallth Dive health Dive in Africa Dive insurance Dive leaders Dive masks Dive medical insurance Dive medicals Dive medicines Dive medicine Dive operators Dive opportunities Dive planning Dive procedures Dive safety 101 Dive safety briefing Dive safety Dive safe Dive skills Dive staff Dive teams Dive travels DiveLIVE DiveTravel Diveleader training Diveleaders Divelights Diver Ethisc Diver Food Diver Health Diver Profile Diver Travel Diver education Diver infliencers Diver on surface Diver recall Diverover 50 Divers Alert Diversafety Divers Divesites Diving Divas Diving Equipment Diving Family Diving Fatalities Diving Feet Diving Helmets Diving Kids Diving Programs Diving Trauma Diving career Diving emergencies Diving emergency management Diving etiquette Diving fit Diving guidelines Diving history Diving injuries Diving science Diving suspended Diving Dizziness Dizzyness Dolphins Domestic Donating Blood Donation Doug Perrine Dowels Dr Rob Schneider Drift diving Drysuit diving Drysuit valves Drysuits Durban Dynamic environment Dyperbaric medicines EAPs EAP EKG EMS EN standards Ear barotrauma Ear pressure Ear wax Ears injuries Eat fish Eco friendly Ecowise Education Electronic Embolisms Emergency Action Plan Emergency Planning Emergency action planning Emergency decompression Emergency plans Emergency treatments Emergency underwater Oxygen Recompression Emergency Endurance Entry Envenomations Enviromental Protection Environmental factors Environmental impact Environmental managment Environmental stewardship Equalisation Equalization Equipment care Equipment failure Equipment inspection Equipment significance Evacuations Evacuation Evaluations Even Breath Evironmetaly friendly Exercise Exercising Exhaustion Exploration dives Exposure Protection Extended divetime Extinction Extinguisher Extreme treatments Eye injuries Eye protection FAQ Face computer Factor V Leiden Failures FalseBay Diving Fatigue Faulty equipment Feet Femal diver Female divers Fenivir Fetus development Field practice Filling stations Fillings Fin Foot Fins Fire Coral Fire Safety Fire extinguisher Firefighting Fires First Aid Equipment First Aid Kit First Aid Trainig First Aid Training First Aid kits First Aid Fish Identification Fish Life Fishing Fish Fit to dive Fitness Levels Fitness Training Fitness evaluation Fitness to dive Fitnesstrainng Fitness Flying Focus lights Food Footissues Foundations Fractures Francesca Diaco Francois Burman Fred Buyle Fredive Free Student cover Free diving Free flow Freedive Competition Rules Freedive Competiton Freedive INstructor Freedive Safety Freedive Training Freedive computer Freedive modes Freedive rescue procedures Freediver Staff Instructor Freediver Freedive Freediving Instructors Freediving performance Freediving Fur rade Galapagos Gar Waterman Gardens of The Queen Gas Density Gas Planning Gas consumption Gas emboli Gas laws Gas management Gas mixes GasPerformance Gasblends Gases Gass bubbles Gastoeusophagus Gastric bypass Gastroenterologist Gas Gear Servicing Germs Geyer Bank Giant Kelp Forest Giant Kelp Giant stride Girls that Scba Gobies Golden fish Gordon Hiles Great White Sharks Green sea turtle Green turles Greenlings Guinness World Record Gutt irritations HBOT HBO HCV HELP HIRA HMLI HMS Britanica Haemorhoid treatment Hand signals Harry Chammas Havanna Hawaii Hawksbill Hazard Description Hazardous Marine life Hazardous marinelife Head injuries Headaches Health practitioner Healthy Food Heart Attack Heart Health Heart Rate monitor Heart fitness Heart rates Heart rate Heart Heat loss Heat stress Helen Walne Heliox Helium Gas Helium Hematoma Hemodynamic Hepatitis C Hepatitus B Hiatal Hernia High Pressure vessels High pressure hoses High temperatures Hip strength Hip surgery Hippocampus History Hole in the heart Hood Hot Human diver Humans Hydrate Hydration Hydrogen Hydroids Hydrostatic pressure Hygiene Hyperbaric Chamber Hyperbaric Oxygen Treatments Hyperbaric Oxygen Hyperbaric research Hyperbaric treatment Hyperbarics Hypertension Hypothermia Hypoxia I-52 found INclusivity IdentiFin Imaging Immersion Immine systems In Water Recompression Increased pressure Indemnity form Indian Ocean Indigo SCuba Indonesia Inert gas Infections Infra red Imaging Inhaca Ocean Alliance Injections Inner ear Instinct Instruction Instructors Insulation Insurance policy Insurance Integrated Physiology International travel International Internship programs Internship Interval training Investigations Irritation Irukandji Syndrome Isotta housing Italy Itchy Rash Its OK Jellyfish Jennifer Hayes Jill Heinerth Joanna Wyrebek John Vowles Joint pain Joshua Journal for Technical Diving Junior Open Water Diver KZN South Coast KZN Karen van den Oever Kate Jonker KateJonker Kelp Forest Kelp forests Kenya Kidneys Kids scubadiver Komati Springs KwaZulu Natal Kwazulu-Natal LED lights LED Labour laws Lake Huron Lara Lambiase Laryngospasm Lauren Arthur Leanne Walmsley Learning to dive Leatherbacks Leatherback Legal Network Legal advice Legislation Lembeh Straights Lenses Leslie Lwaney Leukemis Liability Insurance Liability Risks Liability releases Liability Life expectancy Lifestyle Lighting equipment Lighting Lightroom editing Lights Lionfish Live aboard diving Liveaboard Liver Toxicity Liver diseas Liz Louw Loss of consciousness Lost at sea Lost divers Low Visability Low blood platelets Low blood pressure Low pressure deterioration Low volume masks Lumpsuckers Lung Irritation Lung flexibility Lung function Lung injuries Lung over expansion Lung squeeze Lung surgery Lung MOD MOzambique diving MPA Macro photography Mafia Island Maintenance Malaria Mammalian Dive Response Mammalian effect Manatees Mandarin Fish Marfan syndrome Marine Biologist Marine Biology Marine Mega fauna Marine Science Marine Scientists Marine conservation Marine parks Marine plants Marinelife Marinescience Markus Dirschi Marlin Marne protecte areas Mask clearing Masks Mask Master scuba diver Matty Smith Maximum operating depth Medical FAQ Medical Q Medical emergencies Medical forms Medical oxygen Medical questionaire Medical statement Medical team Medicalquestionaires Medicalresearch Medicalstudents Medication Mehgan Heaney-Grier Membership benefits Menopause Menstruation Mental health Mermaid Danii Mesophotic Metotrexate Mexico Michael Aw Micro Photography Microbubbles Middle ear pressure Mike Bartick Military front press Military Misool Resort Raja Ampat Mixed Gas Mono Fins Mooring lines More pressure Motion sickness Motionsickness Mount Kilimanjaro Mozambique Muck Diving Muscle pain Mycobacterium marinum NDL limits NSRI Narcosis National Geographic Nature Nausea Nauticam Ambassadors Nauticam Ambassador Nautilus Navigation Ndibranchs Neck pain Neoprene layers Neuro assessments Neurocognitive research Neurological assessments Neuromotor exercises New Caledonia Nichola Bird Nicorette Nicotine Nitrogen Narcosis Nitrogen build up Nitrox No Decompression Limits No-decompression limits No-decompression Non-nano zinc oxide Non-rebreather Mask Non-smoking Nondiving related illness Nonrebreather masks Normal Air North Sulawesi Northern Taiwan Nosebleeds Nudibranchs Nuno Gomes Nutrition O2 enriched O2 oxygen provider. O2 providers O2 servicing O2 treatments O2treatments OOxygen maintenance Ocean Alliance Ocean Projects Ocean Research Ocean animals Ocean clean up Ocean community Ocean conservation Ocean life Ocean mammals Ocean migrations Ocean pollution Oceangate Ocean Octopus Oil contamination Olive Ridley Open Ocean Open water divers Operatorethics Optical focus Oral contraseptives Orbital implants Oronasal mask Osteonecrosis Otters Out and about Out of air Outer ears Outreach Overhead Envirenments Oxygen Administration Oxygen Cylinder Oxygen Toxicity Oxygen Units Oxygen deficit Oxygen deicit Oxygen dificiency Oxygen ears Oxygen equipment Oxygen explosions Oxygen kit Oxygen masks Oxygen providers Oxygen safety Oxygen supplies Oxygen supply Oxygen systems Oxygen therapy Oxygen treatment Oxygen P J Prinsloo PADI Freedivers PFI PFOs PFO PJP Tech PTSD Paper Nautilus Paralysis Parentalsupervision Part 3 Partner Training Patent foramen ovale PatentForamen Ovale Pemba Island Peri-peri Divers Personal Perspective Petar Denoble Peter Lindholm Philippine Islands Philippines Phillipines Photographers Photographer Photography tips Photography Physical Fitness Physioball Physiology Physiotherapy Pills Pilot Whale Pistons Planning Plastic pollution Plastic Plimsoll Interface Pneumonia Pneumothorax Poison Pole fishing Polka Dot Bat fish Pollution Pool Diving Pool chemicals Pool maintenance Pool workout Pools Post traumatic Post-dive Potuguese man-of-war Pre-dive fitness Pre-dive Predive check Pregnancy Pregnant divers Preparation Prepared diver Press Release Preventions ProDive Port Elizabeth Product scuba nudi Professional rights Protection Provider course Psycological Pulmanologist Pulmonary Barotrauma Pulmonary Bleb Pulmonary Edema Pulmonary Hypertension Pulse Punture wounds Pure Air Pure Apnea Purge Quit Smoking Q RAID South Africa RCAP REEF RMV ROS Radio communications Range of motion Rashes Reactive oxygen species Rebreather diving Rebreatherdive Recces Rechargeable batteries. Rechargeable Recompression chamber Recompression treatment Recompression Recreational dives Recycle Red SEA Reef Chcek Reef Conservation Reef Environmental Education Foundation Reef protection Reef safe Reef surveyors Refractive correction Regal Sea Goddesses Regulator failure Regulators Regulator Remote areas Remote dive locations Remote islands Renewable Rental gear Report incidents Rescue Divers Rescue Procedure Rescue breathing Rescue breaths Rescue diver Rescue skills Rescue skill Rescue training Rescue Researcher profile Research Respitory Minute Volume Resume diving Return To Diving Return to diving Reuseable items Rhinopias Risk Assessments Risk assesments Risk assessment Risk elements Risk management Risk mitigation Risks of Seizures River diving Riviera Maya Roatan Marine Park Roatan Ronblom Rubber ducks SABS 019 SAC SMB SRC SafariLive Safe diving practices Safety Concerns Safety Gear Safety Stop Safety in Air Safety SaherSafe Barrier Salisbury Island Salish Seas Salty Wanderer Sanitising Sanne Volja Sara Andreotti Sara Banderby Sara Campbell Sardine Run Sargassum sea Saturation Diving Saturation diver Save our seas Schrimps Science of diving Science Scoliosis Scombroid Poisoning Scorpion Fish Scuba Air Quality Scuba Guru Scuba Injury Scuba Instructor Scuba children Scuba divers Scuba dive Scuba diving Scuba education Scuba gear Scuba health Scubalearners Scubalife Sea Horses Sea Turtles Sea rescue Sea slugs Seagrass Sealcolonies Sealife Seals Seasickness Seaweeds Seaweed Sea Self Rescue Send Nudi Shallow Water Blackout Shallow dives Shark Protection Shark Research Shark conservation Shark diving Sharks Shipwrecks Shit Happens Shore entries Shoulder strength Sidemount Sideplank Signalling devices Signs and Symptoms Silty bottoms Sit-ups Sixgill Sharks Skills in action Skin Bends Skin outbreak Skin rash Smart phone photography Snells Window Snorkeling Snorkels Social Distancing Sodwana Bay Solomon Islands Sonnier bank South Africa Southern Sea Otters SpareAir Special Operations Special forces units Sperm Whales Spinal Bend Spinal bends Spinal cord DCS Spinal dura Spinal pain Spinner dolphins Spleen Splits Sports medicine Squeezes Squid Run Stability exercise Stage cylinder Standars Statin Mediction Stay Fit Stay Warm Steel Stefan Randig Stents Step ups Stephen Frink Stepping up Stobes Stockton Rush Stonetown Stretch band exercise Stretch bands Stretching Strobe Lighting Strobes Stroke Submerge tech Submerged Sudafed Sulawesi Sun protection Sun screen Sunscreen Supplemental oxygen Surface Air Consumption Surface Consumption Rate Surface Marker Buoys Surface supplied Air Surfaced Surfers Surgeries Surgery Survivor Suspension training Swim Fitness Swimmers health SwimmingIn wateractivities Swimming Sylvia Earl Symbiosis Symbiosys TRavel safety Tabata protocol Talya Davidoff Tank valve Tanzania Tara Panton Tattoes Tchnical diving Team Awareness Tec Clark Tec divers Tec diving Tech diving Technical Diving Technical diver Technical divng Temperature Homeostatis The Bends The Cavettes The Produce The Titanic Wreck The Wild Coast The greatest Shoal The silent world The truth Thermal Notions Thermoregulation Thomas Peschak Thresher shark Thunder Bay National Marine Sanctuary Tides Tips and trick Tonga Tooth squeeze Transplants Trashbag Trauma Travel Safe Travel destinations Travel smarter Travel tips Travel Tropical Coastal Management Tulamben Tullum Tulum. Tuna Tunnelling Turks and Caicos Turtles Tweezers Ultrsound Umkomaas Unconscious diver Unconsciousness Underground waterways Underground work Underseaa world Underwaater Photos Underwater Photography Underwater Photograper Underwater Photograpgraphy Underwater Photographer Manirelife Underwater Photographers Underwater Research Underwater camera Underwater critters Underwater floral Gardens Underwater hockey Underwater imaging Underwater lights Underwater models Underwater photographer Underwater photography Underwater photos Underwater pho Underwater sound Underwatercommunications Underwater Underwtaer photography University of Stellenbosch Unresponsive Urchins Urinary retention. VGE Vacations Vaccines Vagus nerve Valsalva manoeuvers Valve stem seals Vape Vaping Vasopressors Vasvagal Syncope Venous gas emboli Ventilate Venting Verna van Schak Veterinarian Videography Vincenzo Ferri. Virus infections Volatile fuels WWII wrecks War stories Washout treatments Wastewater Watchman device Water Resistance Water Weakness Weigang Xu Weightloss Weights West Papua Western Cape Diving Wet Lenses Wet diving bell Wetsuit fitting Wetsuites Wetsuits Wetsuit White balance Whitetpped Sharks Wide Angle Photos Wide angles Wildlife park Wildlife Winter Wits Underwater Club Wolf Eels Woman and diving Woman in diving Woman's Health Womans health Woman Women In Diving SA Women and Diving Women in Freediving Women in diving Womens Month Womens health Work of Breathing Workout World Deeepst Dive Record World Records Wound dressings Wreck History Wreck divers Wreck dive Wreck diving Wreck exploration Wreckdiving Wrecks Wrist technology Yachts Yoga Youth diver Zandile Ndholvu Zanzibar Zoology Zooplankton \ Blennies abrasion absolute pressure acoustic neuroma excision adverse seas air-cushioned alert diver altitude alveolar walls anemia antibiotics anticoagulants antiseptics bandages barodontalgia bent-over barbell rows bioassays biodiversity bloodcells blue carbon body art breathing air calories burn canal blockage cannabis oil carbon dioxide toxicity cardiovascular career developments cerebrospinal fluid cervical spine checklist chemo port children child chronic obstructive pulmonary disease clearances closed circuit scuba compressed gass coral growth corrective lenses crystalweed currents cuts cylinder filling daggaolie dagga dead lift decompression algorithms decongestants decongestion deep dive training dehydration discovery dive clubs dive injuries dive medicing dive ready child dive reflex dive tribe divecomputers diver in distress diver rescue diver training dive diving attraction diving hoods doctors dolphns domestic travel dri-suits drowning dry mucous membranes dry suits dry e-cigarettes ear spaces earplugs ears elearning electrolyte imbalance electroytes emergency action plans emergency assessment emergency training environmentally friendly equalising equalizing exposure injuries eyes fEMAL DIVERS fire rescue fish watching fitness Balance fitnes flexible tubing frediving freedivers gas bubble gas poisoning gastric acid gene expression health heartburn heron bridge histidine hospital humidity hypobaric hypoxia immersion and bubble formation immersion pulmonary edema (IPE informal education isopropyl alcohol jaundice join DAN knee lanyard laparoscopic surgery life jackets longevity lower stress lox oxygen level lungs malaise mamalian effect marielife marine pathogens medical Questions medical issues medical procedures medical risk assesment medications mental challenge mental preparedness micro-organisims micro minor illness mucous membranes multilineage dysplasia myelodysplasia nasal steroids nasal near drowning nematocysts neurological newdivers nitrogen bubbles no tanx off-gassed operating theatre operations orthopeadic otitis media out planting outgas pain parameters perforation phillippines phrenic nerve physical challenges pinched nerves plasters pneumoperitoneum polyester-TPU polyether-TPU post dive posture prescription mask preserve prevention professional emergency responders proper equalization psychoactive pulmonary barotrauma. pulmonary injury. pulmunary barotrauma pure oxygen radiation rebreather mask rebreathers retinal detachment risk areas safety stops saturation scissors scuba equipment scuba sea goddesses single use sinus infections situationalawarenes smoking snorkeling. spearfishing spliff sterilising stings strength sub-aquatic sunscreen lotion swimmer's ear swimmer\'s ear swimmers ears tattoo care tecnical diver thermal protection tissue damage toxicity trachea training travel Insurance trimix tympanic membrane unified standards upcycled upwelling virtual coach vision impaired vomiting warmers water quality zinc oxide