Contraindications to scuba diving

The specific physiology of diving and the unforgiving nonrespirable environment make some medical conditions contraindications to diving South Pacific Underwater Medicine Society (SPUMS), 2020. Some conditions may be transient (eg sinus congestion problems) and fitness for diving can be reassessed after the condition has resolved.

Absolute contraindications to scuba diving that limit a diver’s judgement or physical ability to cope with an emergency include:

  • age younger than 14 years (the South Pacific Underwater Medicine Society does not recommend diving for children younger than 14 years)
  • poor general fitness (eg inability to safely cope with the physical demands of diving)
  • visual acuity less than 6/12 in the better eye or both eyes together
  • current mental health symptoms such as psychosis, severe depression and suicidality, paranoia with hallucinations and delusions or significant anxiety with panic attacks
  • cognitive impairment or impaired intellect that prevents a person from learning or retaining the required understanding of safe diving actions.

Absolute contraindications to scuba diving that increase the risk of barotrauma include:

  • an immobile or chronically perforated tympanic membrane1
  • a discharging outer or middle ear
  • teeth with caries, incomplete fillings, or dental work in the previous 24 hours
  • any history of spontaneous pneumothorax
  • previous perforating chest injuries or open chest surgery
  • current upper respiratory tract inflammation (eg sinusitis) or cleft palate (repaired or not)2
  • current asthma that is symptomatic or evident on spirometry3
  • significant obstructive lung disease
  • any chronic or fibrotic lung disease that may alter pulmonary compliance, including cystic fibrosis
  • active pulmonary tuberculosis.

Some conditions increase the risk of barotrauma in scuba diving but may not be absolute contraindications after review by a certified diving doctor. These include:

  • traumatic pneumothorax including previous barotrauma-related pneumothorax
  • chest surgery that has not entered the pleural cavity
  • history of middle ear surgery such as tympanoplasty
  • abdominal herniation.

Diving is not recommended for anyone who may be pregnant because risk to a fetus is unknown.

Certain conditions pose a high risk of death if an acute event (eg loss of consciousness) occurs during a dive and are usually a contraindication. Conditions include:

  • a history of epilepsy or seizures, including any seizure risk higher than in the general population (eg after head injury)4
  • syncope or blackouts that have not been investigated or are at risk of recurring
  • coronary artery disease
  • cardiac failure, cardiomyopathy or any left ventricular dysfunction
  • arrhythmias, arrhythmia predisposition syndromes (eg long QT syndrome), recurrent or unexplained syncope or presyncope, or an implanted defibrillator
  • moderate to severe cardiac valve lesions
  • pulmonary hypertension
  • congenital or structural cardiac disease (eg atrial septal defect or patent foramen ovale5)
  • anticoagulation (other than single agent antiplatelet therapy, such as aspirin) or coagulation disorders
  • sickle cell disease—hypoxia can trigger haemolytic crisis
  • Meniere disease—vertigo, disorientation and altered consciousness can occur.

Some patients might be cleared to dive once assessed and treated by a specialist.

Other conditions where referral to a diving doctor or discussion with a specialist for further opinion should be considered include:

  • age between 14 to 18 years (for whom parental or guardian involvement is also recommended)
  • age 45 years or older (or 35 years or older for people with diabetes or 30 years or older for First Nations peoples)—full cardiovascular risk estimation is required and any increase in risk requires referral for formal assessment6
  • a past history of asthma (eg childhood asthma) or previously abnormal lung function tests—referral recommended (current symptoms or abnormal spirometry are contraindications to diving)
  • obesity—this increases risk of decompression sickness and may reduce physical fitness
  • visual abnormalities that may limit ability to read gauges and dive tables
  • history of migraine with aura (requires screening for associated patent foramen ovale, which is a risk factor for cerebral arterial gas embolism)
  • concussion with recurrent headache, intracranial surgery
  • neurological conditions (eg lower limb weakness due to traumatic nerve injury) where further damage from diving will result in significant functional impairment
  • significant pre-existing hearing loss where further damage from diving will result in significant functional impairment
  • anxiety disorders, hyperactivity and attention deficit disorders, alcohol or illicit drug use7
  • gastrointestinal problems that may cause vomiting or acute distress (eg peptic ulceration, severe reflux)
  • diabetes mellitus8
  • use of prescription or nonprescription medications requires careful assessment. Medications may have altered effects or increase risks associated with diving (eg risk of decompression sickness or nitrogen narcosis). Cardiovascular, respiratory or neurological drugs may be associated with a significant increase in risk.

For further detail, see ‘Guidelines on medical risk assessment for recreational diving’ available to download on the SPUMS website. If there is doubt regarding a person’s fitness to dive, refer for specialist opinion.

1 Diving can resume once the tympanic membrane has been seen to be fully healed.Return
2 These conditions interfere with pressure equalisation and risk barotrauma. Divers with upper respiratory tract inflammation should avoid decongestants and defer diving until symptoms have fully resolved.Return
3 Any past or current history of asthma (symptoms or abnormal lung function tests) requires referral to a certified diving doctor. A person may be cleared to dive after this review if they currently are asymptomatic and have satisfactory lung function.Return
4 Decisions on return to diving after a head injury require assessment of ongoing neurological symptoms and their potential effect on a diver’s cognition and seizure risk; a period of waiting after resolution of symptoms may be advised but advice from a certified diving doctor should be sought.Return
5 Patients with patent foramen ovale or an atrial septal defect are at increased risk of neurological decompression sickness or arterial gas embolism and should be assessed by a certified diving doctor and a cardiologist before being cleared for diving.Return
6 Full cardiovascular assessment should be considered for younger candidates where significant coronary risk factors are present (including obesity, smoking, hypertension, elevated serum lipids or positive family history).Return
7 These can all impair decision-making; in addition, significant alcohol or illicit drug use increase risk of vomiting, dehydration, nitrogen narcosis and decompression sickness.Return
8 Diabetes mellitus is associated with several risks, including hypoglycaemia from increased energy expenditure during diving, and end-organ disease limiting physical ability. Well-controlled diabetics with good understanding of glycaemic control may be able to dive safely in accordance with guidelines for recreational diving with diabetes.Return