Medical FAQs

Here's a list compiled over the years of commonly asked questions. The list was created by DAN MDs and represent specific, evidence-based recommendations our member should take into consideration.


I am an active diving instructor and need to have a molar tooth extracted and get an implant in its place. I would like to know how long you recommend waiting before going back to diving, under the supposition that there are no complications with either the extraction or the implant.
At this point, surgeons have not developed uniform recommendations related to oral surgery and scuba diving: generally, the more complicated the surgery, the longer the wait before diving. Surgical complications will add to this time, as can any underlying medical conditions, tobacco use and alcohol consumption.

During post-surgical osseointegration (the fusion of the implant into the bone), it is necessary to avoid anything that could apply pressure to the skin over the implant and cover screw or the healing abutment.

Diving too soon after surgery with its resultant pressure, no matter how slight, could damage the site. For example, if the regulator’s bite tabs are over the implant site, transmitted biting forces can result in implant failure. There are other considerations as well. Diving should be suspended for as long as it takes to avoid other complications associated with oral surgery:

  • revascularization (resumption of blood flow);
  • stabilization of the implant;
  • oral and sinus cavity pressure changes;
  • ability of the patient to hold a regulator in the mouth; and
  • use of medications for pain or infection.


Bone grafting procedures and sinus surgery are more complex and will require a longer waiting period. The larger the graft site, the longer the wait. Some doctors will recommend avoiding any activity that causes micro-movement for at least six months. It can actually take up to one year for complete bone healing at an implant site. While diving sooner than one year may not cause a problem, your surgeon should determine the appropriate time period. Even if your surgeon doesn’t dive, follow his or her advice.

As your implant is a molar, then the problem with the regulator bite does not apply but the other concerns remain.

I have two medical questions, both related to dental problems: how long should I wait to dive after a tooth extraction? And how long is it recommended not to dive after a bone transplant to place a future screw?
A tooth extraction does not necessarily require to interrupt your diving activity. If you did not have complications, you can dive whenever you want and feel fine. If you have received a bone transplant prior to implantation of dental prostheses, it is advisable to apply a prudent resting period.

Diving does not mean any particular problem for both procedures. Therefore, as soon as your maxillofacial surgeon authorizes you to perform normal activities of daily life, you will also be able to dive again.

I recently returned from a dive vacation. I experienced trouble with a tooth about a week after my return, and three days later required a root canal. My dentist said he knew another diver who had required root canal work; my wife's friend, also a diver, required a root canal too. Is this a coincidence or is it a problem related to diving?
There has been no established cause-and-effect relationship between root canals and scuba diving. It is possible that the repetitive action of clenching a scuba regulator with your teeth may have exacerbated an underlying problem.

Root canal therapy is generally necessary after a tooth nerve has been damaged from a direct blow to the dental area or the result of decay, abscess, or infection.
Most root canals are done in patients who are over 50 years of age and who have had one of these events occur after a lifetime of using their teeth.
In the thousands of certified divers over age 50, root canals are rarely reported. In all likelihood, the problem was just coincidental and would most likely have occured even if you had not participated in scuba diving.
There is a small risk of infection immediately after a root canal, but once you are released by your dentist, you should have no problem when diving.

I’m 45 years old and a diver since 2012. I would like to know if I can dive with inflammatory bowel disease.
Inflammatory bowel disease (IBD) can result from ulcerative colitis or Crohn’s disease. The major symptoms are diarrhea, which can be bloody; abdominal pain; nausea; and vomiting, often with fever and weight loss.

Commonly, IBD usually occurs to divers aged 20 to 40 years and who experience the following: 

  • Intermittent disease with long periods of normal bowel functioning; and 
  • Complications including anemia, electrolyte disturbances, dehydration, poor absorption of fluids, liver disease and generalized fatigue. 

Drug treatment often involves corticosteroids, which can impair one’s ability to fight infections.

Fitness and diving
Someone with symptomatic IBD should not dive until treatment has caused remission and they do not need medication. A person experiencing no significant complication of IBD or its treatment and has adequate cardiovascular fitness could consider diving.

I’m 56 and in good health. Three years ago I had an idiopathic pulmonary embolism. I am no longer taking anticoagulant medication, and I remain very active. Can I dive?
Several things need to be considered when evaluating fitness for diving after a pulmonary embolism. First is the cause, because it is important to determine the risk of recurrence. Determining this risk may be difficult in your case because your embolism was idiopathic (of unknown origin).

Next the damage to the lung must be assessed.
Scarring and/or adhesions may prevent proper gas exchange, making diving unsafe. DAN is not in a position to determine an individual’s fitness for diving; a physician must make that decision. The best way to begin the process of assessing your fitness to dive is to get a high-resolution spiral CT scan to determine if there is damage to the lung tissue. If there isn’t, and exercise tolerance is normal, diving can be considered.
Pulmonary hypertension and other associated medical conditions may restrict your exercise tolerance.
Certain medications can have side effects that might limit your ability to dive safely, so you should discuss all medications you take and your complete medical history with your doctor.
If your doctor approves your return to diving, request this approval in writing so you can provide documentation to dive operators, who will likely require a written statement before allowing you to dive.

Last week I caught a cold and high fever, with respiratory difficulties. My doctor, after a medical examination, diagnosed a bronchospasm and gave me the following medications: 3 days with Azithromycin antibiotic and then Ambroxole. It seems now that I recovered my nasal respiration and I will be clinically checked in the next few days. I would like to have your opinion before diving again.
You can go back to diving safely again only after your doctor confirms that the acute inflammation

at upper airways and bronchial level is completely recovered and thus you may discontinue the medication therapy.

I had a spontaneous pneumothorax a few months ago. How long should I wait before diving again?
Unfortunately for you, nowadays a spontaneous pneumothorax is recognised as an absolute contraindication for diving.

This is because of two reasons:

  1. If it occurred without any injury (so the name “spontaneous”), it can happen again at any time. In fact, there are some statistics showing that half of those persons who had spontaneous pneumothorax in the past, will have it again in future.
  2. If pneumothorax occurs while diving, any decrease of pressure, for example during surfacing, will increase volume of air in the pleural cavity leading to a tension pneumothorax, when internal pressure will compress the lung and the heart.

This is a real life-threatening disorder, especially when occurring underwater, just after surfacing or even on the diving boat. All in all, the risk is too high for potentially fatal consequences, so you should understand that you should avoid diving. And this restriction expands also for any hyperbaric exposures, like for example hyperbaric chambers, even for training purposes.

What are the effects PMS will have on me when I dive?
Premenstrual Syndrome, or PMS, is a group of poorly understood and poorly defined psychophysiological symptoms experienced by many women (25-50 percent of women) at the end of the menstrual cycle, just prior to the menstrual flow. PMS symptoms include mood swings, irritability, decreased mental alertness, tension, fatigue, depression, headaches, bloating, swelling, breast tenderness, joint pain and food cravings. Severe premenstrual syndrome has been found to exacerbate underlying emotional disorders. Although progesterone is used in some cases, no consistent, simple treatments are available.


Research has shown that accidents in general are more common among women during PMS. If women suffer from premenstrual syndrome, it may be wise to dive conservatively during this time. There is no scientific evidence, however, that they are more susceptible to decompression illness or dive injuries/accidents.

Also, individuals with evidence of depression or antisocial tendencies should be evaluated for their fitness to participate in diving: they may pose a risk to themselves or a dive buddy.

I would like some information regarding the best contraceptive method to use, more compatible with diving. I am oriented towards the copper-based intrauterine device (IUD), which does not involve taking hormones.
At present, there are no medical indications that favor one contraceptive method over another with regard to being exposed to decompression stress. There are no clinical trials or data on the IUD, however I do not see any particular contraindications with regard to its use while diving.

As a rule, if no side effects or a documented greater individual risk of thrombotic events are present (but this would also affect the prescription of the contraceptive), also the use of oral contraceptives does not have any contraindications connected to diving.

This said, the practice of choosing more conservative dive profiles is strongly advised (dives without decompression stops, no more than two dives a day, maximum depth within 30 meters, bottom time within 70-75% of the maximum limit, possible use of Nitrox with dive times calculated for air).

I have a question concerning breastfeeding and diving. My wife and I have just had a baby. She is still breastfeeding and if everything goes well, she would like to carry on for the next 4 months at least. On the other hand, she is eager to resume diving. And I wondered if the nitrogen that gradually saturates our tissues and which will necessarily go into the milk can have an impact on the baby. We dive at a maximum depth of 30 m and stay within the limits of no-decompression diving. Have any studies been done in this field? What could be the impact on the baby? I think my wife will express her milk before diving so that she can feed the baby with non-nitrogenated milk, but how long does it take for nitrogen to desaturate the breast tissue?
There is no accumulation of nitrogen in breast milk, and even if this were the case, drinking this milk would not cause any risk of decompression in the baby. Your wife can therefore resume diving a few weeks after giving birth (in general, it is recommended to wait at least 3 weeks to recover from the “trauma” of childbirth and hormonal changes).

In the first few months, we recommend to stay within the limits of “no-deco dives”, i.e. dives which don’t have mandatory decompression stops – after all, the bodily changes induced by these 9 months of pregnancy should not be underestimated.

Only one disadvantage may occur when your wife dives during the months she is still breastfeeding: the pressure exerted by the dive suit on the chest and on the breasts could (in some cases) reduce milk production (it is a known technique for woman who want to stop breastfeeding, to wear tight clothes or bandages around the chest).
But as your wife will not wear the dive suit all day, this risk isn’t very high.

Is it safe to breastfeed an infant after diving?
Yes, it is safe. A mother’s breast milk is not adversely affected by diving, and there is no risk of decompression sickness for the infant.

Although nitrogen accumulates in all of the tissues and fluids of the mother’s body, washout of inert gas occurs quickly after a safe dive.
Insignificant amounts of nitrogen may be present in the mother’s breast milk, but it is inert and poses no risk to the infant. However, because of the possible risk of bacterial growth on the skin under a suit, careful cleansing of the breast after diving and before feeding may help prevent systemic illness.

I've recently been asked to teach a course to a 16-year-old autistic girl. I would like to know if it's possible and if there are any potential consequences or contraindications.
Autism, for countless reasons, presents many contraindications to diving. Among others, a communication deficit that could pose the girl in great danger in the underwater environment.

Since the evaluation is extremely delicate and complex, I advise you to talk to a specialist in diving medicine, who should visit the girl and can then give you a direct assessment.
His/her opinion will then need to be compared and cross-checked with that of the neuropsichiatrist who follows the girl.

I regularly suffer from a headache after diving. I do not suffer from migraine and do not suffer from a headache when I do short dives. What can be wrong?
Chronically recurrent headaches after long dives can have numerous causes.

Most are:

  1. Accumulation of carbon dioxide in the blood caused by wrong breathing techniques. These headaches are very severe and last quite a long time.
  2. Unfavorable diving position with overextension of the cervical spine. Often hardening of the neck muscles can be found.
  3. Biting the mouthpiece of the regulator too hard can lead to overstressing the chewing and postural neck muscles and can therefore also lead to severe headaches, which should, however, resolve swiftly after the dive.

I have a student who wants to learn to dive, but has cerebral palsy. What are the issues?
This condition describes brain injury present at birth and which is manifested by some degree of weakness. This includes a wide variety of clinical problems, ranging from ‘walks abnormally’ to very severe and disabling handicaps.

Some cases present accompanying seizures, learning disability and speech defects. Diving fitness depends entirely on the extent of disability in the individual case.

Candidates with mild problems may qualify; candidates with more severe disabilities may qualify through one of the scuba programmes for disabled people.
The absence of seizures and the ability to master water skills are particularly important.
For participation in scuba, case-by-case selection is needed.

When my son was young, he went through a period where he fainted several times. The doctors never really knew why and he seemed to grow out of it. Now he wants to learn to dive. Will his history of fainting present a problem?
This is a difficult question to answer since many variables can cause transient alteration of consciousness. These alterations of consciousness include fainting, a drop in blood pressure which is very common in young people, an alteration in heart rhythm that is more common in older people, the effects of medication and psychological events, such as hallucinations.

As with epilepsy, any loss of consciousness underwater is likely to have a bad outcome. When diving using nitrox or mixed gas as a breathing gas, increased partial pressures of oxygen can increase the likelihood of seizures. Increased carbon dioxide may also increase seizure risk. The best advice is to get a precise diagnosis of the cause of these altered states of consciousness: effective treatment is often available. You cannot make a reasonable fitness-to-dive decision until this is sorted out. It may take some time and a visit to a neurologist or other specialist is necessary.

I love to dive, but was recently diagnosed with Multiple Sclerosis. Can I continue?
This immunologic disease occurring in both young and middle-aged people is characterised by episodes of neurologic dysfunction, often separated by remission. He extent of disability is quite variable. Treatment has improved in recent years.

Fitness & Diving

  1. There is no evidence that diving in itself has an effect on the disease. About 20 years ago an unsuccessful effort was made to treat MS with hyperbaric oxygen. Patients neither suffered nor benefited from this treatment.
  2. Persons with MS are advised not to exercise to the point of exhaustion and to avoid becoming chilled or overheated. Diving candidates with MS should respect that advice.
  3. In each individual case, consider whether the candidate can handle the physical load and master the water skills. Diving candidates should talk to their DMO and neurologist about diving.

I’m an instructor. Few day ago a guy came to me with a valid fit to dive certificate. He told me he suffers from epilepsy and he’s under treatment. I’m worried he can have a seizure when underwater, can you please give me some advice?
Regarding your student and in general any form of epilepsy, as long as the following three conditions are met, you can consider diving: - free of attacks for more than 5 years  - normal EEG  - medical therapy is no longer necessary

In this specific case the third condition is not satisfied, therefore I suggest you to recommend your student to be assessed by a specialist in diving and hyperbaric medicine in order to evaluate his fitness to dive in relation with his medical history

I am a beginner diver and I have difficulty equalising my ears. I have heard that I should not dive if I use nasal decongestants, but is it safe to dive if I use nasal steroids?
It is very common for new divers to experience difficulty to equilise their middle ear spaces. As you gain experience and learn the techniques that work best for you, you will find equilisation easier in general. There is little scientific data regarding any specific medication and diving, but based on the known side-effects of steroids nasal sprays, there is little reason to suspect that they would be problematic for divers.

Even though the fast-acting nature of decongestants can be appealing, there are several reasons why steroids may provide a safer option.
The swelling and inflammation of the cells lining the Eustachian tubes, middle ear space and sinuses may lead to occlusion and barotrauma. The mucous membranes lining these structures are vascularised and decongestants provide a short-term solution to congestion by constricting the blood vessels in the mucous membranes, which decreases swelling.

When the decongestants wear off, however, the blood vessels are no longer constricted. The after effect is that the blood vessels will swell and may become more engorged with blood that before, which is known as the rebound-effect.
Unlike decongestants, steroids do not act as vasoconstrictors, so there is no rebound. Another disadvantage of decongestants is that they are only intended for short-term use and may lose effectiveness with habitual use.
The steroid, fluticasone propionate, and similar medications, on the other hand, are intended to be used over substantially longer periods of time than decongestants. So prevention of a middle-ear barotrauma is best achieved by avoiding nasal decongestants and by training the diver in correct middle-ear equalization techniques during descent.

I underwent a tympanoplasty (repair of ear drum perforation) and mastoidectomy (removal of infection from the bone behind the ear) surgery 4 weeks ago. When can I start diving again, or should I stop diving now?
Operative procedures in the area of the middle ear can lead to very different conditions regarding ventilation. A mastoidectomy is an extremely complex surgery. While after most interventions involving a tympanoplasty diving fitness can be quickly re-established in case of a robust eardrum, which needs to be determined by an ENT doctor, a mastoidectomy has a minimum healing phase of 8 to 12 weeks.

After this, again, an ENT doctor has to decide whether diving can be resumed.
The altered anatomy of the ear after complete healing absolutely necessitates the precise examination by a specialist who tests the endurance and equalization capacity in such cases. 

I understand that feeling tired after a dive may be a symptom of decompression sickness, but I almost always feel tired after diving. Should I be concerned?
The expectation of normal (i.e., nonpathological) tiredness following diving varies from person to person. Factors such as individual fitness, thermal stress, gear constriction, diving skill, work completed during the dive, psychological stress (positive or negative) and distraction can all affect how tired one feels.

While these variables make it difficult to quantify tiredness as a symptom of decompression sickness (DCS), unusual fatigue has long been documented in association with other symptoms of DCS.

The mechanism behind fatigue as a symptom of DCS remains elusive, although it is possibly a response to a cascade of physiological events taking place in various tissues.
It could be through direct stimulation of nervous tissues or indirectly through the stimulation of other tissues. It is possible that the attention currently being directed toward identifying biochemical markers of DCS will help resolve the questions.

In the meantime, it is reasonable to say that DCS represents a complex, multifocal response to a decompression injury. Unusual or “undue fatigue” (that in excess of normal fatigue for a given individual and diving exposure) is a recognized symptom.

Showing 21 to 40 of 60 entries.