Medical Conditions That Can Prevent You Scuba Diving

Medical Conditions That Can Prevent You Scuba Diving

Medical conditions that can prevent you from scuba diving include asthma, diabetes, heart disease, pneumothorax, and a history of seizures. Some medical conditions pose a severe risk to diving, while other conditions are relative or temporary. 

Do you remember filling out a medical statement form when you signed up for scuba training, or when you headed out for a fun dive with a dive centre? These forms are not to make you feel bad, they are there for your safety and others. 

Some medical conditions can prevent you from scuba diving.

I’m not saying you need to be an athlete to go scuba diving…however, scuba diving is a sport that requires good health. This means that some people have to be extra careful, as there are a few medical conditions that require a physical evaluation by a doctor before you can hit the water. 

The reason for medical clearance is due to previous injuries or surgeries resulting in weakened body tissues which may not be obvious on land but with increased pressure underwater, can pose major issues.

For example, if you have any scar tissue, you are more prone to nitrogen bubble formation, increasing the risk of decompression sickness (DCI), also known as ‘the bends.

In this article, we will go through medical conditions that can prevent you from going scuba diving.

Medical Conditions That Can Prevent You Scuba Diving

  • Behavioural Health
  • Cardiovascular 
  • Neurological
  • Pulmonary
  • Gastrointestinal
  • Haematological
  • Metabolic & Endocrinological 
  • Orthopaedic
  • Otolaryngological 

Behavioural Health

Behavioural conditions are one of the most tricky medical conditions to evaluate.

While a history of a psychiatric disease does not automatically prevent you from scuba diving, psychotropic medications can.

If you take medication that affects your awareness, or you take benzodiazepines or narcotics that increase seizures, you will need medical clearance from your psychiatric doctor. 

People that suffer from severe depression, bipolar disorder, psychosis, or suffer from an addiction to drugs or alcohol abuse, should not go scuba diving. 

People that dive and take selective serotonin reuptake inhibitors (SSRIs) may be acceptable if medication has been used longer than one month without suffering any side effects, has been signed off by a physician to dive, and the diver is aware of the risks. 

Severe Risk Conditions

  • Major depression
  • Bipolar disorder
  • History of frequent panic attacks
  • Drug and/or alcohol abuse

Relative Risk Conditions

  • Anxiety disorder
  • History of drug and/or alcohol abuse
  • History of major depression & bipolar disorder
  • Use of psychotropic medications 
  • Claustrophobia/agoraphobia 


Scuba diving can put some strain on the heart, especially if you have high blood pressure.

Around 30% of scuba diving related deaths involve cardiovascular problems. If you suffer from extreme chest pain, a heart murmur, hypertension, or premature death in your family, you must seek medical clearance from a cardiologist before taking the plunge into the ocean or any diving training. 

Severe Risk Conditions

  • Coronary artery disease (untreated)
  • Cardiomyopathy (dilated/obstructive)
  • Heart failure
  • Pulmonary hypertension
  • Long QT syndrome
  • Paroxysmal arrhythmias
  • Valvular lesions
  • Congenital cardiac disease
  • Implanted cardiac defibrillator
  • Chronic immersion pulmonary edema

Relative Risk Conditions

  • Coronary heart disease (treated)
  • History of dysrhythmias 
  • Pacemakers
  • A single episode of immersion pulmonary edema
  • Marfan syndrome
  • Left ventricular hypertrophy 


If you have a neurological illness that affects the spinal cord or peripheral nerves, you may not be able to go scuba diving.

However, if you are assessed and cleared by a medical professional, then you can technically dive, but some dive professionals can still refuse to take you diving. 

People that suffer from seizures or epilepsy episodes are not allowed to go scuba diving. If you have a history of seizures, even if it has been longer than 5 years, you could have one at any time. If you were to have a seizure when scuba diving, it is likely to be fatal. 

Severe Risk Conditions

  • Epilepsy
  • History of seizures 
  • History of transient ischemic attacks or cerebrovascular accidents
  • History of serious DCI with residual deficits
  • Recurrent fainting episodes

Relative Risk Conditions

  • History of a serious head injury
  • Herniated nucleus pulposus
  • Intracranial tumour or aneurysm
  • MS (multiple sclerosis)
  • Trigeminal neuralgia
  • History of a spinal cord or brain injury
  • Parkinson’s disease


Any medical condition that impedes airflow from the lungs puts a diver at great risk of pulmonary over-inflation, alveolar ruptures, and arterial/cerebral air embolisms. 

If you have asthma, it is recommended that you do not go diving, especially if your asthma is uncontrolled.

The reason for this is that asthma causes constriction of the airway (in the bronchioles) making it difficult to breathe, and underwater you will not have access to your inhaler.

If air becomes trapped during an asthma attack underwater, it can rupture the alveolar wall as it expands during ascent. This can inject air into the bloodstream, which can cause a collapsed lung, leading to an arterial gas embolism (AGE).

If you suffer from AGE, your brain can become starved of oxygen causing a stroke which is usually fatal underwater. If you are someone that suffers from chronic or daily asthma symptoms you should completely avoid scuba diving. 

Saying that, if you suffer from only mild symptoms of asthma, it may be possible to get clearance from your doctor that states you are fit and healthy, that you have a normal pulmonary function, and you have passed the exercise test. 

If a pneumothorax happens when diving, it can be fatal. When divers ascend the trapped gas that expands could produce a tension pneumothorax

COVID-19 has added an extra layer of complexity when it comes to dive fitness. People that have suffered from COVID-19 may need more than a pulmonary evaluation before diving. As we still do not know the long-term effects of COVID-19, changes in medical clearance and scuba diving could change. 

Severe Risk Conditions

  • History of pneumothorax
  • Respiratory impairment
  • Pulmonary hypertension

Relative Risk Conditions

  • Asthma
  • Reactive airway disease
  • Exercise-induced bronchospasm
  • Solid/cystic/cavitating lesions
  • Thoracic surgery
  • Obesity
  • History of immersion pulmonary edema or restrictive disease
  • Sleep apnea
  • Interstitial lung disease 


Scuba divers should have no gastrointestinal (GI) conditions that increase vomiting (emesis), reflux episodes, bleeding, perforation, diarrhoea, or extreme pain.

As a diver surfaces, trapped gas expands, which can lead to ruptures in the GI tract or emesis. If emesis occurs underwater it can cause a diver to drown. 

Severe Risk Conditions

  • Active inflammatory bowel disease
  • Gastric outlet obstruction
  • Chronic/recurrent small bowel obstruction
  • Extreme cases of gastroesophageal reflux
  • Achalasia 
  • Paraesophageal hernia 
  • Gastroparesis

Relative Risk Conditions

  • Inflammatory bowel disease
  • Functional bowel disorders

Temporary Risk Conditions

  • Peptic ulcer disease
  • Unrepaired hernia in abdominal walls


Heart disease is associated with many health conditions that can prevent you from going scuba diving.

Scuba diving with haematological abnormalities can increase the chance of getting DCI. If you have had heart surgery or a heart attack, it is recommended to wait at least six months before going scuba diving. After waiting at least six months, you will still need to visit a cardiologist to test your fitness level and get approval for scuba diving.

If you have high blood pressure, it can increase your risk of having a stroke and heart attack underwater.

If you are to have a stroke or heart attack underwater, it is usually fatal.

People that control their blood pressure with medications and a good diet, and have medical clearance from a professional medical examiner, should be fine to go scuba diving. But, if your blood pressure is not controlled and your doctor does not recommend you go scuba diving, you will have to sit this dive out I’m afraid!

If you have a history of heart disease, always make sure you visit your doctor or cardiologist for an evaluation before you plan a diving trip. 

Relative Risk Conditions

  • Sickle cell disease
  • Polycythemia vera
  • Leukaemia
  • Haemophilia
  • Recent blood transfusion surgery
  • Recent thrombotic episodes
  • Hereditary hypercoagulability conditions 

Temporary Risk Conditions

  • Anticoagulant prescriptions 

Metabolic & Endocrinological

These conditions are related to a diver’s ability to tolerate moderate exercise and environmental stress. Obesity and diabetes can increase the chances of DCI and are both risk factors of coronary artery disease. 

Diabetes is another medical condition that could prevent you from scuba diving.

Depending on what type of diabetes you have, diabetes is when your body does not make enough insulin, or your body cannot utilize insulin normally. If your blood sugar is too low or too high, scuba diving can become extremely risky. It is recommended if you frequently have low or high blood sugar, you shouldn’t go scuba diving.

Saying that, if you control your diabetes, it may be possible to go scuba diving, but you will need to visit your doctor to get them to sign you off as “fit for diving”.

Severe Risk Conditions

  • Rapid changes of consciousness due to hypoglycemia medications or insulin therapy in diabetics
  • Pregnancy – decompression can affect fetus health 

Relative Risk Conditions

  • Hormonal excess/deficiency
  • Obesity
  • Renal insufficiency 

Orthopaedic (musculoskeletal system)

The ability to move is essential for recreational scuba diving.

You must be able to enter and exit the water from either the shore or on a boat and be able to kick underwater. Some orthopaedic medical conditions such as amputation and scoliosis can prevent you from doing those things, especially with heavy scuba gear and/or diving in cold conditions. 

Relative Risk Conditions

  • Amputation
  • Scoliosis
  • Aseptic necrosis
  • Disc prolapse
  • Habitual Luxation
  • Degenerative joint diseases

Temporary Risk Conditions

  • Severe back pain
  • Fractures that are yet to heal
  • Muscle-tendon & ligament injuries

Otolaryngological (Ear, Head & Neck)

Equalizing during scuba diving is essential for all scuba divers, particularly during ascent and descent.

As the inner ear is filled with fluid, it makes it non-compressible.

If you have had inner ear surgery, the chances of rupture are higher, which can be fatal. If you have had a midface fracture, your mandibular and maxillary must function properly to hold the regulator mouthpiece in your mouth and allow you to swallow.

People that have had midface fractures are more prone to barotrauma and rupturing air-filled cavities

Severe Risk Conditions

  • Monomeric tympanic membrane
  • Tube myringotomy
  • History of stapedectomy
  • History of ossicular chain surgery
  • History of inner ear surgery
  • Facial nerve paralysis from barotrauma
  • Inner ear disease
  • Upper airway obstruction that is uncorrected
  • Tracheostomy
  • Uncorrected laryngocele
  • History of vestibular DCI
  • Symptomatic nasal/sinus polyps
  • Ménièr’s disease

Relative Risk Conditions

  • Recurrent otitis externa
  • Eustachian tube dysfunction
  • Recurrent otitis media/sinusitis
  • History of tympanoplasty
  • History of mastoidectomy
  • Facial nerve paralysis not associated with barotrauma injuries
  • Full prosthodontic devices
  • History of midface fractures
  • Unhealed oral surgery
  • History of round window rupture
  • Otosclerosis

Before you go out on any dive trip or holiday, it is essential to make sure you have dive insurance that covers you if something goes wrong.

Don’t Forget Your Dive Insurance!

Before you go out on any dive trip or holiday, it is essential to make sure you have insurance that covers you if something goes wrong. Check out our dive insurance article for more information.

Or go straight to these dive insurance company websites:


Diver Alert Network (DAN)

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Final Thoughts

If you know you suffer from any chronic illnesses it is strongly recommended to always see a medical examiner to clear you for scuba diving and provide you with a medical statement approving you for this fun and exciting sport

Safety is the number one priority when scuba diving, which is why you fill in a medical questionnaire before every dive you do.

Scuba diving is an amazing hobby however your health is a priority and diving without making the dive centre or your dive instructor know of any previous or current medical conditions will not only put your safety at risk, but also the safety of others underwater.

This is particularly important when diving in remote areas that are far away from medical care and assistance. 

Even though scuba diving accidents are rare, many accidents occur due to undiagnosed and undisclosed medical conditions. Never lie on a diving medical form. Remember that a dive instructor has the right to refuse training, even if your doctor has medically signed you off. 

If your doctor or dive instructor has refused you to dive because of medical clearance, they could have potentially saved your life!

Thank you for reading, and remember to always be a safe diver!

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Darby Bonner

Darby is a marine biologist and PADI scuba diving instructor from the UK. With over ten years of diving experience, she has visited some of the best dive destinations in the world. Currently, Darby is living in Bali, Indonesia and regularly dives at some of the most beautiful dive sites in the Indian Ocean. Her passion for the ocean led her to study seals, publish a paper, and become a marine mammal medic. In the future, she hopes to complete her master’s in marine science, and of course, continue her love for teaching and diving!

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