Sight Search

Posts with the category “return-to-diving”

0
Hazards in Wreck Diving
July 29th, 2021
Nearly every ocean, sea and lake holds a world of shipwreck exploration for advanced open-water divers. Each lost ship, submarine, airplane and even the odd locomotive is a time capsule waiting for an...  Read More
by DAN Team
0
Exercising After a Break
July 29th, 2021
There is no perfect time for a workout, and you have to balance all your daily requirements, but people who plan for and prioritize exercise are more successful in the long run. Plan for your workout ...  Read More
by DAN Team
0
Outer- and Inner Ear Infections
July 29th, 2021
Trauma to the external canal disrupts the protective epithelium that, along with earwax, prevents infection....  Read More
by DAN Team
0
Return to Freeding after Cancer Treatment
July 29th, 2021
Shallow water, however, does not always mean it’s safe. Your lungs must tolerate rapid changes of volume with the pressure at shallower depths, and the greatest changes occur in the first 33 feet (10 ...  Read More
by DAN Team
0
Hiatal Hernia
July 29th, 2021
There is always some degree of DCS risk any time you dive, so take measures to minimize that risk. Continuously monitor yourself for signs and symptoms of DCS following a dive, and seek medical attent...  Read More
by DAN Team
0
Shallow-Water Arterial Gas Embolisms
July 29th, 2021
The pressure change during ascent is greatest closer to the surface. But since it doesn’t take much overpressure to cause barotrauma, it can also occur if divers hold their breath at depth, especiall...  Read More
by DAN Team
0
Shooting in a Turbid Environment
July 29th, 2021
Turbid water may not appear brown or green from the surface — in many cases the water looks entirely different once we drop in and begin the dive. All water is turbid to some degree. Understanding wha...  Read More
by DAN Team
0
Surviving Triple Dangers in the Maldives
July 29th, 2021
f your breathing-gas supply is critically low, get to the surface at a safe ascent rate, and then monitor for signs of DCI. It is better to deal with DCI on the surface than to run out of breathing ga...  Read More
by DAN Team
0
An Insider’s Guide to Roatán
July 28th, 2021
Roatán also offers convenient and low-maintenance diving. The waters are clear, blue, calm and typically not subject to strong currents. The short, easy boat rides provide a lot of scheduling flexibil...  Read More
by DAN Team
0
Magic in the Gulf
July 28th, 2021
Near the turn of the 20th century, fishers described the two picturesque reefs full of colorful marine life about 100 miles south of the Texas–Louisiana border as “flower gardens,” and the name stuck....  Read More
by DAN Team
0
Pack Your Camera Equipment for a Dive Trip
July 13th, 2021
There is simply no way one can risk packing your valuable camera equipment into your check-in bags! Which means you must pack your expensive, valuable, fragile camera equipment into your hand luggage...  Read More
by DAN Team
0
When Should I Call My Doctor?
May 21st, 2021
Photo by Lenetstan/Shutterstock If you notice health changes during or soon after a dive, you should assume that it is related to diving. The most likely culprit is decompression illness (DCI), the li...  Read More
by DAN Team
0
Dive Operations and COVID-19: Prepping for Return FAQs
May 21st, 2021
As more and more people are vaccinated and national and local lockdown orders are lifted, divers and dive business owners are eagerly returning to the water. The following Q&As have been compiled from...  Read More
by DAN Team
0
Medical Emergencies Abroad
May 21st, 2021
Best Practices for International Diving Incident PreparednessDivers have the unique opportunity to explore remote areas of our ocean planet. Unfortunately, a dive trip can quickly turn into a misadven...  Read More
by DAN Team
0
Dive Accident Coverage Vs. Medical & Travel Insurance: Do You Need Both?
May 21st, 2021
It is true that some medical insurance include cover for diving injuries. However, divers who have tried to go this route soon discover that it is not easy to work with a medical insurance when trying...  Read More
by DAN Team
0
Experience Matters
May 21st, 2021
By Cheryl Hughes After reading two recent Alert Diver articles — one by a woman who saved her husband in Cozumel and the other about how the simple act of saying some wise words may have saved another...  Read More
by DAN Team
0
Avoiding Panic After Regulator Failure
May 21st, 2021
Divers are responsible for doing a proper buddy check, having a plan for handling emergencies and making the decision to abort a dive if necessary. Photograph by Stephen Frink  By Nick UresinEditor’s ...  Read More
by DAN Team
0
Gear Maintenance: Protect Your Investment and Prevent Dive Accidents
May 20th, 2021
The adage “an ounce of prevention is worth a pound of cure” dates back to the 18th century but still rings true today. Proactive measures such as dental checkups, travel immunizations and oil changes ...  Read More
by DAN Team
0
Hose Failure
May 20th, 2021
Hose degradation is potentially an unseen hazard that you should consider during your predive check. (Please note that in the pictures shown, the failed hoses do not represent products supplied by the...  Read More
by DAN Team
0
Invisible Crystals
May 20th, 2021
By Francois Burman, Pr. Eng, MSc Scuba equipment failure or malfunction is a relatively rare factor in diving-related accidents and fatalities. When it does occur, the most common and hazardous malfun...  Read More
by DAN Team
0
Are 6351-T6 Alloy Scuba Cylinders Safe to Use?
May 20th, 2021
By Mark A. Gresham, President, PSI-PCI In recent months, two 6351-T6 alloy scuba cylinders ruptured, and evidence suggests the cause was sustained load cracking, a metallurgical anomaly. While those p...  Read More
by DAN Team
0
New Gear Orientation
May 20th, 2021
Whether you are renting or buying new gear, take time to become familiar with it before diving in open water. Photo by Stephen Frink By Jim Gunderson Whether you are a new diver buying your first set ...  Read More
by DAN Team
0
How To Clean Your Scuba Equipment
May 20th, 2021
The risk of acquiring a disease or infection from contaminated scuba equipment is low; however, there are many benefits to using clean, well-cared-for scuba equipment. Properly maintained dive gear ca...  Read More
by DAN Team
0
How Old Is Too Old
May 20th, 2021
By Francois Burman, Pr. Eng, MSc., and Peter Buzzacott, Ph.D., MPH Everyone loves the smell of a new car, but eventually the car develops problems, and you realize current models have new safety featu...  Read More
by DAN Team
0
Over-the-Counter Medications
April 22nd, 2021
By definition, over-the-counter (OTC) medications are the classification of drugs considered safe for consumer use based solely on their labeling. When used as directed, they present a minimum risk an...  Read More
by DAN Team
0
High-Pressure Ophthalmology
April 22nd, 2021
Our eyes normally exist in a world where the pressure around them is the result of the combined weight of all of the gases in the earth’s atmosphere. Diving exposes the eyes to increased pressure. Whi...  Read More
by DAN Team
0
Member to Member: Guidelines for Seniors
April 22nd, 2021
As divers get older, DAN® recommends getting annual physicals, staying active and fit, diving within physical limits and avoiding difficult or dangerous diving conditions.There is little concrete advi...  Read More
by DAN Team
0
Seasickness Prevention and Treatment
April 22nd, 2021
Some of the world’s best dive sites are accessible only by boat, and unfortunately seasickness prevents some scuba divers from visiting their dream destinations. Unmanaged seasickness will make any bo...  Read More
by DAN Team
0
Juggling Physical Exercise and Diving
April 16th, 2021
If you want to dive, you need to be ready. Readiness entails medical, psychological and physical fitness, appropriate knowledge and adequate physical skills. If you exercise regularly at an intensity ...  Read More
by DAN Team
0
Risk Factors For Heart Disease
April 16th, 2021
Heart health is essential to the safety of all divers, symptoms of heart conditions are often subtle or easily missed. In some cases, the first indication of a serious cardiac problem may be a heart a...  Read More
by DAN Team
0
Health Concerns for Divers Over 50
April 16th, 2021
Getting older doesn’t have to mean give up on diving, but divers over 50 should be aware of common medical issues that may interfere with safe diving. Heart disease, respiratory disease and musculoske...  Read More
by DAN Team
0
When to Consult a Health-Care Provider Before Engaging in Physical Activities
April 16th, 2021
Date: 15 December 2013 | Author Petar Denoble MD, DSc. Physical activity (PA) is beneficial for health, but the transition from a sedentary lifestyle to PA or a change in the level of habitual PA may ...  Read More
by DAN Team
0
Diving After Bariatric Surgery
April 16th, 2021
I’m an instructor, and I have a student who completed his pool sessions, but he had gastric bypass surgery before he could do his open-water dives. Before I allow him to continue with his training, I’...  Read More
by DAN Team
0
Fitness for Diving
April 16th, 2021
There are moments when scuba diving feels effortless: drifting over a shallow reef or descending through clear water toward a sandy bottom. But diving can also be strenuous — when swimming against a c...  Read More
by DAN Team
0
Scuba Diving and Diabetes
April 15th, 2021
For many years the medical community discouraged people with diabetes from scuba diving. A Divers Alert Network® (DAN®) survey in 1996, however, revealed that nearly 200 of its members were divers wit...  Read More
by DAN Team
0
Your Lungs and Diving
April 15th, 2021
Date: 1 May 2017 | Author:By Jack Meintjes, MBChB, DOM, FCPHM(SA) Occ Med, MMed Diving imposes significant challenges to the respiratory system. Lung conditions are among the most common reasons peopl...  Read More
by DAN Team
0
Wisdom Tooth Extraction and Diving
April 15th, 2021
Wisdom teeth are permanent molars that usually emerge during the late teens or early twenties. It’s not uncommon for these teeth to be associated with pain or complications. Dentists often recommend h...  Read More
by DAN Team
0
Flying After Diving
April 15th, 2021
When flying after diving, the ascent to altitude increases the risk of decompression sickness (DCS) because of the additional reduction in atmospheric pressure. The higher the altitude, the greater th...  Read More
by DAN Team
0
Unexpected Weight Loss
April 15th, 2021
A dropped weight belt caused a runaway ascentReported StoryTowards the end of the dive, at about 6 m (20 ft) depth, my weight belt fell off (the buckle came loose from the strap). I exhaled and dumped...  Read More
by DAN Team
0
Unintended Rapid Ascent Due to Uncontrolled Inflation
April 15th, 2021
A runaway ascent ends the diving on a liveaboard holidayReported StoryDiving from a liveaboard near a remote island in South America, I was hanging out on a coral ledge at 93 fsw (28 msw) watching Ham...  Read More
by DAN Team

Categories

 2021
 April
Aqua Pool Noodle ExercisesUnderwater Photographer and DAN Member Madelein Wolfaardt10 Simple Things You Can Do to Improve Your Underwater PhotographyCOVID-19 and Diving: March 2021 UpdateDiver Return After COVID-19 Infection (DRACO): A Longitudinal AssessmentGuidelines for Lifelong Medical Fitness to DiveExperienceFitness Myth or Fitness Fact?The Safety of Sports for Athletes With Implantable Cardioverter-DefibrillatorsCardiovascular Fitness and DivingHypertensionPatent Foramen Ovale (PFO)Headaches and DivingMiddle-Ear Barotrauma (MEBT)O’Neill Grading SystemMask Squeeze (Facial Barotrauma)Sinus BarotraumaInner-Ear Barotrauma (IEBT)Middle-Ear EqualisationAlternobaric VertigoDecompression IllnessOn-Site Neurological ExaminationTreating Decompression Sickness (The Bends)Top 5 Factors That Increase Your Risk of the BendsHow to Avoid Rapid Ascents and Arterial Gas EmbolismUnintended Rapid Ascent Due to Uncontrolled InflationUnexpected Weight LossFlying After DivingWisdom Tooth Extraction and DivingYour Lungs and DivingScuba Diving and DiabetesDiving after COVID-19: What We Know TodaySwimmer’s Ear (Otitis Externa)Motion SicknessFitness for DivingDiving After Bariatric SurgeryWhen to Consult a Health-Care Provider Before Engaging in Physical ActivitiesFinding Your FitnessHealth Concerns for Divers Over 50Risk Factors For Heart DiseaseJuggling Physical Exercise and DivingSeasickness Prevention and TreatmentMember to Member: Guidelines for SeniorsHigh-Pressure OphthalmologyOver-the-Counter Medications
immersion and bubble formation Accidents Acid reflux Acute ailments After anaesthesia Air Quality Air exchange centre Air hose failure Air supply Airway control Air Alert Diver Magazine Alternative gas mix Altitude changes Altitude diving Altitude sickness Aluminium Oxide Ama divers Amino acids Anaerobic Metabolism Animal life Annual renewal Apnea Apnoea Aquatic life Aquatics and Scuba Diving Archaeology Arterial Gas Embolisms Arterial gas embolism Arthroscopic surgery Aspirin Aurel hygiene BCD BHP BLS BWARF Back adjustment Back pain Back treatment Backextensors Badages Bag valve mask Bahamas Balancing Bandaids Barbell back squat Barometric pressure Barotrauma Basic Life Support Batteries Bench press Benign prostate hyperplasia Benzophenones Beth Neale Beyond Standards Biophysics Black Blood flow Blood thinners Blue Wilderness Blurred vision Boat safety Boesmans gat Boesmansgat Bone fractures Bouyancy compensators Boyle's Law Boyle\'s Law Bradycardia Brain Breast Cancer Breath Hold Diving Breath holding Breath hold Breath-hold Breathing Gas Breathing gas contamination Breathing Breathold diving Bright Bank Broken bones Bruising Bubbleformation Buddy Exercise Buddy checks Buoyancy Burnshield CGASA CMAS CO2 COVID-19 Updates COVID-19 COVID CPR Cabin pressure Caissons diseas California Camera equipment Camera settings Cameras Cancer Remission Cancer treatments Cancer Cannabis and diving Cannabis Cape Town Dive Festival Cape Town Dive Sites Cape Town CapeTown Carbon Monoxide Carbon dioxide Cardio health Cardiological Cardiomyopathy Caribbean Carmel Bay Cave diving Challenging Environments Chamber Safety Chamber science Charging batteries Charles' Law Charles\' Law Charles\\\' Law Charles\\\\\\\' Law Charles\\\\\\\\\\\\\\\' Law Charlie Warland Chemotherapy Chest compressions Children diving Chiropractic Chlorophll Christina Mittermeier Citizen Conservation Cleaning products Closed Circuit Rebreathers Coastalexcursion Cold Water Cold care ColdWater Cold Commercial diving Commercial schools Composition Compressed Air Compressed gas Consercation Conservation Photographer Conservation photography Conservation Contact lenses Contaminants Contaminated air Coral Conservation Coral Reefs Coral Restoration Coral bleaching CoralGroupers Corals Core strength Corona virus Coro Costamed Chamber Courtactions Cozumel Cristina Mittermeier Crohns disease Crowns Crystal build up Crystallizing hoses Cutaneous decompression Cylinder Ruptures Cylinder handwheel Cylinder valves DAN Courses DAN Profile DAN Researchers DAN medics DAN members DAN report DCI DCS Decompressions sickness DCS theories DCS DEMP DM training DNA DReams Dalton's Law Dalton\'s Law Dalton\\\'s Law Dalton\\\\\\\'s Law Dalton\\\\\\\\\\\\\\\'s Law Danel Wenzel Dangerous Marinelife Dauin island Dean's Blue Hole Dean\'s Blue Hole Deco dives Decompression Illness Decompression Sickness Decompression Stress Decompression illsnes Decompression treatment Decompression Decorator crabs Deep diving Deep water exploration Deepest SCUBA Dive Delayed Offgassing Dental Dever Health Diaphragms Diopter Diseases Disinfection Dive Buddy Dive Chamber Dive Computer Dive Destinations Dive H Dive Industry Dive Instruction Dive Instructor Dive Medical Form Dive Medical Dive Practices Dive Pros Dive Research Dive Safety Tips Dive South Africa Dive Training Dive Travel Dive accidents Dive buddies Dive computers Dive courses Dive excursions Dive exercise Dive experience Dive fitness Dive gear Dive heallth Dive health Dive medicals Dive medicines Dive medicine Dive operators Dive planning Dive safety 101 Dive safety Dive safe Dive skills Dive staff Dive travels DiveLIVE Diveleader training Diveleaders Diver Health Diver Profile Diver infliencers Diver on surface Divers Alert Divesites Diving Divas Diving Kids Diving Programs Diving Trauma Diving career Diving emergencies Diving emergency management Diving fit Diving guidelines Diving injuries Diving suspended Diving Dizziness Dolphins Domestic Donation Dowels Dr Rob Schneider Drift diving Drysuit diving Drysuit valves Drysuits Dyperbaric medicines EAPs EAP Ear pressure Ear wax Ears injuries Eco friendly Education Electronic Emergency action planning Emergency decompression Emergency plans Emergency underwater Oxygen Recompression Emergency Enviromental Protection Environmental factors Environmental impact Environmental managment Equalisation Equipment care Equipment failure Equipment inspection Evacuations Evacuation Evaluations Even Breath Exercise Exhaustion Exposure Protection Extended divetime Extinguisher Extreme treatments Eye injuries FAQ Factor V Leiden Failures FalseBay Diving Fatigue Faulty equipment Female divers Fetus development Fillings Fire Coral Fire Safety Firefighting First Aid Equipment First Aid Kit First Aid Training First Aid kits Fish Identification Fish Life Fish Fit to dive Fitness Training Fitness to dive Fitnesstrainng Fitness Flying Focus lights Fractures Francesca Diaco Francois Burman Fredive Free Student cover Free diving Free flow Freedive INstructor Freedive Training Freediver Freediving Instructors Freediving performance Freediving Gas Density Gas consumption Gas laws Gas mixes GasPerformance Gases Gass bubbles Gastoeusophagus Gastric bypass Gastroenterologist Gear Servicing Germs Geyer Bank Giant Kelp Forest Giant Kelp Gordon Hiles Great White Sharks Guinness World Record Gutt irritations HCV HELP HIRA HMLI HMS Britanica Haemorhoid treatment Hazard Description Hazardous Marine life Hazardous marinelife Health practitioner Heart Attack Heart Health Heart Rate monitor Heart fitness Heart rates Heart rate Heart Heat stress Helium Hepatitis C Hepatitus B Hiatal Hernia High Pressure vessels High temperatures Hip strength Hip surgery Hippocampus History Hot Humans Hydrate Hydration Hydrogen Hydroids Hydrostatic pressure Hygiene Hyperbaric Chamber Hyperbaric research Hyperbarics Hypothermia Hypoxia I-52 found IdentiFin Imaging Immersion Immine systems In Water Recompression Indemnity form Indian Ocean Indonesia Inert gas Infections Infra red Imaging Injections Inner ear Instinct Instruction Instructors Insurance Integrated Physiology International travel International Interval training Irritation Irukandji Syndrome Isotta housing Joint pain Junior Open Water Diver KZN South Coast Karen van den Oever Kate Jonker KateJonker Kidneys Kids scubadiver Komati Springs KwaZulu Natal Labour laws Laryngospasm Lauren Arthur Learning to dive Legal Network Legal advice Legislation Lenses Leukemis Liability Risks Liability releases Liability Life expectancy Lifestyle Lightroom editing Live aboard diving Liver Toxicity Liver diseas Liz Louw Low blood pressure Low pressure deterioration Low volume masks Lung Irritation Lung function Lung injuries Lung squeeze Lung surgery Lung MOD Macro photography Maintenance Malaria Mammalian Dive Response Mammalian effect Mandarin Fish Marine Biology Marine Scientists Marine conservation Marine parks Marinelife Masks Master scuba diver Maximum operating depth Medical Q Medical emergencies Medical questionaire Medical statement Medicalresearch Medication Mehgan Heaney-Grier Mermaid Danii Mesophotic Michael Aw Middle ear pressure Mike Bartick Military front press Mixed Gas Mono Fins Mooring lines More pressure Motion sickness Mozambique Muscle pain Mycobacterium marinum National Geographic Nausea Nautilus Neck pain Neoprene layers Neuro assessments Neurological assessments Nitrogen Narcosis Nitrogen build up Nitrox No-decompression Non-nano zinc oxide Non-rebreather Mask Nonrebreather masks Normal Air Nosebleeds Nuno Gomes O2 providers O2 servicing OOxygen maintenance Ocean Research Ocean pollution Oil contamination Open water divers Optical focus Orbital implants Oronasal mask Osteonecrosis Out and about Out of air Outer ears Outreach Overhead Envirenments Oxygen Administration Oxygen Cylinder Oxygen Units Oxygen deficit Oxygen deicit Oxygen dificiency Oxygen ears Oxygen equipment Oxygen masks Oxygen supplies Oxygen supply Oxygen systems Oxygen therapy Oxygen P J Prinsloo PADI Freedivers PFI PJP Tech Parentalsupervision Part 3 Partner Training Perspective Philippine Islands Philippines Phillipines Photographers Photography tips Photography Physical Fitness Physioball Physiology Physiotherapy Pills Pistons Planning Plastic Pneumonia Pneumothorax Poison Pollution Pool Diving Pool workout Post-dive Pre-dive Predive check Pregnancy Pregnant divers Preparation Prepared diver Press Release Preventions Professional rights Provider course Psycological Pulmanologist Pulmonary Barotrauma Pulmonary Bleb Pulmonary Edema Pulse Punture wounds Pure Apnea Purge RAID South Africa RCAP REEF Radio communications Range of motion Rashes Rebreather diving Rebreatherdive Rechargeable batteries. Recompression chamber Recompression treatment Recompression Recycle Reef Chcek Reef Conservation Reef safe Reef surveyors Refractive correction Regulator failure Regulators Regulator Remote areas Renewable Report incidents Rescue Divers Rescue Procedure Rescue breathing Rescue breaths Rescue training Rescue Resume diving Return To Diving Return to diving Risk Assessments Risk assesments Risk assessment Risk elements Risk management Roatan Marine Park Roatan SABS 019 SMB SafariLive Safety Stop Safety SaherSafe Barrier Salty Wanderer Sanitising Sara Andreotti Sardine Run Saturation Diving Save our seas Science Scombroid Poisoning Scuba Air Quality Scuba Guru Scuba Injury Scuba Instructor Scuba children Scuba dive Scuba education Scuba health Scubalearners Scubalife Sea Horses Sealife Sea Shallow dives Shark Protection Shark Research Shark conservation Shark diving Sharks Shipwrecks Shoulder strength Sideplank Signs and Symptoms Sit-ups Skin Bends Skin outbreak Skin rash Snorkeling Snorkels Social Distancing Sodwana Bay Solomon Islands Sonnier bank South Africa Spinal bends Spinal cord DCS Spinal pain Splits Squeezes Stability exercise Standars Stay Fit Stents Step ups Stephen Frink Stepping up Strobe Lighting Stroke Submerge tech Submerged Sudafed Sulawesi Sun protection Sunscreen Supplemental oxygen Surface Marker Buoys Surface supplied Air Surfaced Surgeries Surgery Suspension training TRavel safety Tabata protocol Talya Davidoff Tattoes Tec Clark Technical Diving Technical divng The Bends The truth Thermal Notions Tides Tips and trick Tooth squeeze Transplants Travel smarter Travel tips Travel Tropical Coastal Management Tunnelling Tweezers Ultrsound Umkomaas Unconsciousness Underground work Underseaa world Underwaater Photos Underwater floral Gardens Underwater hockey Underwater photographer Underwater photography Underwater pho University of Stellenbosch Urinary retention. Vaccines Vagus nerve Valsalva manoeuvers Valve stem seals Vape Vaping Vasopressors Vasvagal Syncope Venting Verna van Schak Virus infections Volatile fuels WWII wrecks War stories Washout treatments Wastewater Watchman device Water Resistance Water Weakness Weigang Xu Weights West Papua Western Cape Diving Wet Lenses Wet diving bell Wetsuit fitting Wetsuites Wetsuits White balance Wide Angle Photos Wide angles Wildlife Winter Wits Underwater Club Woman in diving Womans health Woman Women In Diving SA Women and Diving Women in diving Womens health Work of Breathing Workout World Deeepst Dive Record World Records Wound dressings Wreck divers Wreck dive Wreck diving Wreckdiving Wrecks Yoga Youth diver Zandile Ndholvu Zoology 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 body art breathing air calories burn carbon dioxide toxicity cardiovascular cerebrospinal fluid cervical spine checklist chemo port children child chronic obstructive pulmonary disease clearances closed circuit scuba corrective lenses currents cuts dead lift decompression algorithms decongestants decongestion dehydration dive injuries dive medicing dive ready child dive reflex dive tribe diver in distress diver rescue diver training dive diving attraction doctors domestic travel dri-suits drowning dry mucous membranes dry suits dry e-cigarettes ear spaces elearning electrolyte imbalance electroytes emergency action plans emergency assessment emergency training environmentally friendly equalising equalizing exposure injuries eyes fEMAL DIVERS fire rescue fitnes flexible tubing frediving freedivers gas bubble gas poisoning gastric acid gene expression health heartburn histidine hospital humidity immersion and bubble formation immersion pulmonary edema (IPE isopropyl alcohol jaundice join DAN knee laparoscopic surgery longevity lower stress malaise marielife marine pathogens medical issues medical procedures medical risk assesment medications mental challenge mental preparedness micro-organisims micro minor illness mucous membranes nasal steroids nasal near drowning nematocysts neurological newdivers nitrogen bubbles off-gassed operating theatre operations orthopeadic otitis media outgas pain perforation phillippines phrenic nerve physical challenges pinched nerves plasters pneumoperitoneum polyester-TPU polyether-TPU post dive posture prescription mask preserve prevention proper equalization psychoactive pulmonary barotrauma. pulmonary injury. pulmunary barotrauma radiation rebreather mask rebreathers retinal detachment risk areas safety stops saturation scissors scuba equipment scuba single use sinus infections smoking snorkeling. spearfishing sterilising stings strength sub-aquatic sunscreen lotion swimmers ears tattoo care tecnical diver thermal protection tissue damage toxicity training trimix unified standards upwelling vision impaired warmers water quality zinc oxide