Sight Search

Scuba Diving and Life Expectancy

By Peter Buzzacott, MPH, Ph.D.

A study of 2,872 pairs of Danish twins concluded that only about 25 percent of life expectancy is attributable to genetics; the other 75 percent is likely due to lifestyle factors.

(1) Twenty years after this was published in 1996, a study sponsored by National Geographic identified five places in the world where, per capita, people reach 100 years old 10 times more frequently than they do in the United States.

(2) A team of researchers visited those five places to investigate what lifestyle factors might explain this remarkable longevity; while there, they interviewed 263 centenarians. They found these common factors: leading an active lifestyle, applying mechanisms for lowering stress, having a sense of purpose and belonging to the right tribe (a group of people who share similar interests).

In addition to the factors that are common among the world's oldest residents, many other factors might add a few years to our life expectancy. For example, in 2013 the American Heart Association published a statement that concluded owning a dog probably decreases the risk of cardiovascular disease.3 All this research made us wonder how recreational scuba diving affects life expectancy. We asked the experts.

Diving burns more calories than many people think. It is a very gentle form of exercise, but it is exercise nonetheless. Given that the diving population is aging steadily, do you think this type of cardiovascular exercise might be beneficial for divers, on average, or could the added cardiovascular stress be potentially harmful?

Ingrid Eftedal, Ph.D.: Diving is associated with environmental factors that affect the cardiovascular system, and as long as the total amount of physiological stress is limited and the diver is reasonably fit, no data indicate that diving is harmful to the cardiovascular system. In addition to the health-promoting effects of exercise, one may speculate that diving could have additional benefits for the heart. It has been known for some time that breathing high amounts of oxygen activates an important type of proteins known as molecular chaperones (for historical reasons they are sometimes called heat shock proteins). Some of these molecular chaperones directly protect the heart from injury; extra oxygen is sometimes administered to patients before heart surgery for this reason.

Dawn Kernagis, Ph.D.: Scuba diving can be a fantastic way to burn calories, with a recreational dive burning an estimated 300 to 600 calories per hour depending on temperature and activity level. Although most recreational diving can be very relaxing while still involving increased activity and low levels of joint stress, which is beneficial to individual health, some forms of diving can be strenuous and could put an individual with predisposing conditions at potential risk of injury or incident. It's important to remember that physical fitness is a major factor in determining potential risk with any form of increased physical activity, so risk associated with increased activity will largely depend on a diver's overall physical condition.

When divers breathe air or nitrox at depth, reactive oxygen species are produced. Otherwise known as free radicals, these molecules have been found to be negatively associated with diseases and aging. On the other hand, regular exposure to low levels of oxidative stress might lead to immune responses that are similar to acclimatization. Do you think exposing ourselves to oxidative stress builds resilience in divers or has undesirable consequences?

Kernagis: As with most biological systems, there is an optimal balance with respect to the degree of oxidative stress we are exposed to. Scuba diving can lead to a state of increased oxidative stress in which increased production of free radicals occurs not only due to increased physical activity but also due to the changes in the environmental conditions underwater (e.g., exposure to heat or cold, breathing high-pressure oxygen, being in a high-pressure environment). The combined influence of these diving-related factors on free radical production and the long-term effects on diver resilience and health have yet to be studied in depth but will be important in future research.

Eftedal: Environmentally imposed stress — oxidative stress in particular — is a hot topic in research. Oxidative stress is a double-edged sword. Current knowledge indicates that our cells need a certain quantity of free radicals for biological signal transduction. When the production of free radicals exceeds the body's antioxidant capacity, however, the radicals may harm cell membranes, proteins and DNA, advancing cell aging processes and potentially causing gene mutations that may lead to diseases such as cancer. There is a vital balance, and the immune system appears to be involved in maintaining it. Still, there is nothing to indicate that safe diving destroys the balance between good and bad oxidative stress.

Compared with nondivers who are the same age, same gender and live in the same state, divers are thought to be just as likely to have high blood pressure and/or high cholesterol but less likely to smoke or be obese. Having children is known to increase life expectancy (maybe because the kids can look after their aging parents), but active divers are thought to be 25 percent less likely to have children. On the other hand, divers are much more likely than nondivers to visit a doctor each year. With regard to these lifestyle factors, how do you think divers might fare in the long run compared with nondivers?

Eftedal: I believe that healthy lifestyle choices, careful diving among them, are likely to lead to lower frequency of disease in the long run. Choosing activities you enjoy makes life more interesting, whether or not it is longer.

Kernagis: The factors listed previously, in addition to numerous additional factors — including alcohol consumption, sleep quality, environmental exposures, fitness and nutrition — will have varying impacts on long-term health and wellness. Genetics will also play a role in how these factors interplay and ultimately affect a diver's health. Generalizing about nondivers versus divers is difficult. An individual who doesn't dive might be active in another way that has positive influential factors on his or her overall lifestyle. A healthy diver who is relatively active, doesn't smoke and follows a balanced diet, however, will have lower risks for certain diseases and injuries that could decrease quality of life or overall lifespan for others.

Compared with the rest of the population, divers are traditionally thought to have, on average, higher levels of education and higher incomes. This might translate into better nutrition, safer cars and fewer poor health decisions. On the other hand, it might mean faster cars and greater indulgence. How likely is it that better education and higher earnings over the lifespan might affect longevity?

Kernagis: Previous research has frequently pointed to a correlation between increased lifespans and improved education or higher income. A recent study emphasized that, between these two factors, higher education is a better predictor of longer lifespan.4 The study determined that more education can lead to improved cognitive abilities, which lead to better choices for health- and wellness-driving behaviors. The link between health and income is likely due to the influence of education status on earnings: Better education is often correlated with a higher income.

Eftedal: To my knowledge, better education is a predictor of higher life expectancy on its own. From there, it becomes hard to discern factors on the levels of causation versus association (e.g., higher earnings tend to follow education). One additional factor — improved gender balance with women moving into traditionally male-dominated fields — may make a positive difference for risk management.

Some recreational dives may produce bubbles that cause no symptoms, and bubbles have been linked to endothelial damage (damage to the lining of our blood vessels). Could bubbles be good for us by cleaning plaque out of our blood vessels or regularly renewing the lining? Or are they probably all bad news for divers?

Eftedal: Intravascular bubbles are interesting; they appear so frequently in diving yet only occasionally cause injury or disease. I am not convinced that bubbles have anatomy on their side for acting as pipe cleaners though. Vascular damage, including atherosclerotic plaque, typically occurs in arteries, whereas decompression-induced bubbles are usually found in veins, where the blood pressure is lower. What we observe will always depend on the tools we use, however, and when it comes to bubbles I am sure there is much left to explore — good and bad.

Kernagis: While numerous studies have demonstrated transient endothelial dysfunction because of vascular bubbles, we have not extensively studied potential beneficial effects of bubbles passing through our blood vessels.

When subjected to environmental stresses, humans respond through genetic up or down regulation. Is it possible that regular divers have greater resilience to other environmental stresses because they dive? What about greater resistance to diseases such as cancer?

Kernagis: Diving exposures, in addition to other exposures such as exercise, can precondition individuals for protection in subsequent dives. It has been suggested that this preconditioning could also increase resilience in other environmental extremes, such as hypoxia or environmental stressors that affect the immune system, but more studies need to be conducted to fully assess this potential effect of diving.

Eftedal: Yes, there are genetic data that indicate that regular divers may develop resilience. Along with Croatian researchers, we compared experienced technical divers to nondivers a few years ago. We found that the divers had specific genetic activity changes in their blood cells compared with the nondivers and that these changes might counteract negative effects of oxidative stress. Although diving may promote resilience on a basal biological level, however, we cannot say whether this affects cancer risk. Published data on cancer mainly concerns professional divers who may also have been exposed to chemical pollutants at work, which puts them in a different category than sport and recreational divers.

Recent research suggests that recreational diving is relatively safe, with around two deaths per million scuba dives.5 Despite that, drowning is the most common cause of death in recreational diving. How might a relatively small risk of accidental drowning affect the average life expectancy of divers?

Eftedal: Although drowning is a risk not to be taken lightly, I believe that the health benefits of physical exercise in general, including diving, are more likely to affect life expectancy of divers as a group.

Kernagis: Given the extremely low mortality rate in recreational diving, I don't believe the risk of accidental drowning will have a significant impact on the average life expectancy of divers overall. Divers can minimize their risk of accidental drowning or other types of dive accidents even further, however, by following safe diving practices.

Finally, if we were to conduct a twins study and follow thousands of pairs of twins where one twin scuba dives and the other does not, do you think we might see a difference in life expectancy?

Eftedal: This would be a dream design for research: the perfectly controlled study. If I were to gamble, my bet would be that even with the risks involved in diving, you would find a higher number of centenarians among the diving twins because of acquired acclimatization against environmentally imposed stress.

Kernagis
: To truly assess the impact of diving on life expectancy, each pair of twins would need to live an otherwise equivalent lifestyle. Factors that are known influences on longevity such as nutrition, physical activity, environmental exposure and psychological stress would have to be the same for both twins from birth.


References
1. Herskind AM, McGue M, Holm NV, Sorensen TI, Harvald B, Vaupel JW. The heritability of human longevity: a population-based study of 2872 Danish twin pairs born 1870-1900. Human Genetics 1996; 97(3):319-23.
2. Buettner D, Skemp S. Blue Zones: Lessons from the world's longest lived. American Journal of Lifestyle Medicine. 2016; 10(5):318-21.
3. Levine GN, Allen K, Braun LT, Christian HE, Friedmann E, Taubert KA, et al. Pet ownership and cardiovascular risk: a scientific statement from the American Heart Association. Circulation 2013 June 11; 127(23):2353-63.
4. Lutz W, Kebede E. Education and health: redrawing the Preston curve. Population and Development Review 2018; 44(2):343-61.
5. Buzzacott P, Schiller D, Crain J, Denoble PJ. Epidemiology of morbidity and mortality in US and Canadian recreational scuba diving. Public Health 2018; 155:62-68.

Meet the Experts
Ingrid Eftedal, Ph.D., is a researcher and project manager in the Department of Circulation and Medical Imaging at the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway. She is a civil engineer with expertise in biophysics and medical technology; her Ph.D. is in molecular biology. Eftedal's work focuses on how the body reacts and acclimatizes to the diving environment.

Dawn Kernagis, Ph.D., is a research scientist at the Florida Institute for Human and Machine Cognition, where she specializes in human performance optimization and risk mitigation. She has a biochemistry degree from North Carolina State University and a Ph.D. from Duke University, where she studied gene array-based diagnostic development in the settings of undersea medicine and cancer.

© Alert Diver — Q3 Summer 2018

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