Welcome to Q&A on Diving Medicine

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Q. We have an upcoming scuba trip planned, and I will still be taking antibiotics (Flagyl) [Flagyl is an antibiotic that is useful in preventing infections from water-borne organisms]
A. There are no reported problems with Flagyl and diving. The medication should not cause a problem with the diving environment. Check out the warnings about alcohol and Flagyl. There is some concern about interactions with alcohol for at least three days after you stop taking the medication.


Q. I have a diver who is suffering from Anorexia. She is pitifully underweight and would like to join us for a weekend of diving. Is it advisable for someone with Anorexia to dive? Is it dangerous if she does do the dives? (from a diving instructor)
A. Most people with Anorexia have reduced exercise tolerance and strength. She is likely to have difficulty with lifting gear, etc, and may get fatigued with the swimming involved. Most people with anorexia also have psychological problems, and might have difficulty with anxiety or panic. You should also note if she is taking any medication for the disorder.

Dry Mouth

Q. Five years ago I underwent radiation therapy for Squamous Cell Carcinoma. I have been cancer free ever since. The area that was irradiated was my head, neck and upper chest. I am in excellent health today, I try to stay in shape and exercise regularly. My ears equalize pressure well and I have 95% lung capacity. My problem is that I have reduced salivary function. I know I can use a full face mask and breathe through my nose to scuba, but I'm wondering if there are any other factors I need to consider or if there are any other options I should look into? Mouth breathing leaves me so dried out it's painful so I need an alternative. I'd like to know if there are specific things I should have my doctor look for or check out.
A. Using a full face mask is complicated, and requires special training. Most full face masks incorporate an oro-nasal mask with a regulator. You might not solve the problem of mouth breathing unless you use a free flowing mask or helmet, in that case, you will need surface-supplied air due to the high gas volume needs. You might consider using some form of a water injector in your mouthpiece that would add a fine water mist to your breathing air, or a tube that would allow you to draw in some drinking water to wet your mouth periodically. You could also limit your dives to 30-40 minutes so that you can get your mouth rehydrated before severe drying occurred. Head and neck radiation can cause problems with clearing ears and sinuses. You should be sure all sinuses and your ears can be equalized. Occasionally radiation of your type can caused some lung scarring that could increase risk for lung barotrauma. A lung CT scan to identify abnormal areas of lung tissue is helpful in evaluating this problem.

Intracranial Aneurysm

Q. I have been diving for 6 years and recently was found to have a large intracranial aneurysm. I underwent surgery but still have a residual aneurysm that will need more surgery. There is very little information available regarding aneurysms and diving. I have spoken several times with experts who advised that I give up diving because the increased blood pressure could expand or even rupture the aneurysm with diving. It seems that there is so much physical activity with the diving experience both on and under water that it would be wiser not to dive. Is there anything else you could add to this?
A. All of us in medicine treat intracranial aneurysms with respect because of the catastrophic results of rupture or leak. The greatest stimulus to rupture is hypertension, but the elevated blood pressure that is know to occur with exercise also can cause the aneurysm to rupture or leak. My advice is to avoid diving due to this risk.

Cataract Surgery

Q. I am a 44 y.o. female who two months ago underwent cataract surgery to the right eye, and one month ago, underwent the same procedure for my left eye. The procedures were successful, and included insertion of an acrylic lens in both eyes. Removal of the cataracts was by ultrasound with an incision that doesn't require stitches. What is your recommendation on duration of time to hold off on either swimming or SCUBA diving?
A. The ophthalmologists say you can get back to diving three months after cataract surgery. You need to have all remnants of air absorbed from your eye and the healing complete. You might wait the 3 months, then have an eye exam to be sure all is well before returning to diving.

Free Diving

Q. I have become very interested in free diving, because I find repetitive diving with compressed air to be annoying with all the equipment, carrying tanks, keeping track of bottom times, etc. I have found free diving to be more enjoyable since most of the diving where I live is in 40 feet or less of water. I noticed over time my ability to dive has increased. What physiological changes cause this to happen? Does the red blood cell count increase in free divers over time? I have read that extended exposure to altitude increases blood cell counts in human beings. Does this happen to free divers? Will free diving damage my pulmonary health over time? if it can what are the exposure levels that cause this (i.e. bottom times, depths, etc)? I read the scubamed article on decompression sickness while free diving, what I am asking here is any other possible health damage, such as damage to heart and lungs over time due to free diving.
A. There are no lung injuries from free diving unless you dive to extreme depths (over 250 feet) where you could sustain a lung squeeze. The record for free diving is near 500 feet, so you are not likely to injure your lungs at usual free diving depths. Your improved performance is more likely a learned tolerance to elevated Carbon Dioxide levels in the blood. Increasing CO2 tolerance results from training, but remember that you can get shallow water blackout from low oxygen in the blood by breath holding too long. A tolerance to CO2 makes blackout more likely. To avoid shallow water blackout, avoid excess hyperventilation before you dive. There is no documented increase in red blood cells form free diving, and, with the exception of lung squeeze at extreme depths, no damage to hear or lungs has been recorded.

Muscle cramps

Q. I am 53 years old, and have noted recently that I get muscle cramps after about 1 hour of diving. I have tried Potassium from bananas and pills, it seemed to help a little. I don't use a lot of salt in my diet, trying to control my blood pressure. Can there be anything else I could be doing to help stop these cramps?
A. Muscle cramps are most commonly a sign of inadequate conditioning. You need to swim more with your fins on to improve muscle conditioning. Be sure your fins are not too big, some of the large fins cause too high a load on the leg muscles and cause cramping. Cramping can be caused by low sodium, low potassium, low calcium, or low magnesium. If you are taking a diuretic for hypertension you could have electrolyte imbalances. These can be measured with a blood test. Other causes include the Statin drugs used to lower cholesterol, inadequate circulation to the legs due to blocked arteries (detected by a physical examination), and high levels of caffeine intake. A few people have rare causes like muscular dystrophy or enzyme defects in the muscles that block normal muscle metabolism. If you had an inherited muscle disorder, it would usually be evident earlier in your life. Check with your physician for evaluation of the cramps.

Updated 7/30/01


Q. Five years ago, I had an angioplasty done. The Doc said the heart attack was just starting as I lay on the emergency room table and the clot buster was applied before any damage was done. I came through with basically no damage. I have not dived since the incident and have changed my eating habits and now eat right, sleep right and exercise. What is your opinion about recertification? I am 55 years old, 6'2" and 235 pounds.
A. Many people have returned to sport diving after having an angioplasty. There are several measures that will provide a basis for return to diving. First, you must have reasonable exercise tolerance. You should have an exercise test to determine if you can exercise without developing ischemia (lack of oxygen to the heart). I usually recommend capacity to 13 mets, or stage 4 on a Bruce exercise protocol. If you can get to this level (12 minutes on the test) without ischemia or serious arrhythmias, you should be able to tolerate moderate stress sport diving. In addition, your heart should be functioning normally. You should not have any evidence of heart failure or left ventricular dysfunction. Work at improving you physical condition and losing some weight. Most people who meet the criteria noted above can return to conservative, warm water sport diving.

No Brain Injury from Free Diving

Q. I am becoming interested in free diving and I am wondering how safe extended breath holding is, especially from a neurological standpoint. It seems that I have heard at some time from a source that seemed reliable (perhaps from an old CPR training session) that an unconscious person who is not breathing would be in danger of suffering brain damage after 4 minutes or so. Is it really safe to hold one's breath for two or three minutes or more at a time? And if the answer is yes, how can this be so and how long can your brain go without oxygen without sustaining damage?
A. The 4 minute limit is related to a cardiac arrest. When the heart stops, no blood gets to the brain at all, and there is usually a 4-5 minute window where the circulation can be re-established without brain damage. Breath holding for 4 minutes when the heart is pumping, and blood is flowing normally to the brain, is quite possible, and no brain damage would be expected. When doing voluntary breath holding, the falling oxygen and the rising carbon dioxide in the blood force you to breath before brain injury occurs.

Coronary Stent

Q. I had a heart attack 2 1\ 2 years ago. The cardiologists inserted a stent in one of my coronary arteries and I have a 50% blockage in another artery. Since then I have passed all my stress tests, I backpack, bike and exercise every day. I just became certified for diving with my doctor's ok. Can anything happen to my stent at deeper depths. I haven't been below 35 feet yet.
A. The key to safe diving in cases of coronary narrowing is the ability to exercise safely. If you had a stent and another artery is 50% narrowed, you need to be tested to determine if there is evidence of inadequate blood flow to the heart muscle. I usually recommend that divers be able to exercise to a level of 13 mets or stage 4 on a Bruce protocol to be sure diving will be safe. Although some people consider this to be a high workload, it covers all the demands of diving which might include swimming in a current or assisting another diver. Usual sport diving in temperate waters, with minimal current does not require this level of exercise, but the reserve capacity is needed for safety. You should have an exercise test periodically if you are physically active in any type of sports or exercise to be sure you have adequate exercise reserve to avoid situations where blood flow to the heart muscle is inadequate (ischemia).

Heart Attack

Q. I began diving several years ago, and have logged some 40 dives. I am 50 years old and had a heart attack 10 months ago. I required angioplasty and stent placement. There was minimal damage seen on stress thallium scan, which is normal as of this month. I am fully recovered physically, and in fact am in the best "shape" I have been in for 25 years. I go to the gym almost every day and do 30" on stairmaster followed by light weight lifting, or I run 5 miles. I quit smoking 10 months ago, have normal cholesterol. I am taking 12.5 mg of atenolol/day, prinivil (2.5 mg/d), lipitor (20 mg/d) and aspirin(one/day). My resting BP is about 110/60, and my heart rate is in the 50's. My cardiologist has given me the go ahead to dive. Are there any specific cardiac risks for me to worry about, either as regards my history or my current meds?
A. I suggest that you wait at least 6 months after stent placement to be sure they are stable, and you have passed the time where it is likely to renarrow. The rate of renarrowing for stents is 20-30%, and renarrowing usually occurs in the first 6 months. You should continue with your exercise and fitness program, have a stress test at about 6 months after the stent was placed. If you can reach 13 mets without ischemia, safe diving is usually possible. The medications are not known to interact with diving, although lipitor 20 mg daily will sometimes cause muscle cramps that might be aggravated by exercise or cold water. I also suggest that you confine your diving to warm water, with calm sea state conditions.

Diving and Tampons

Q. Do tampons have, or cause, air pockets that I should be concerned about while diving (particularly during ascent)? Is it better not to wear them? My instructor advised that since they are not in an enclosed space, they should not be a problem. Any advice would be appreciated.
A. There are many divers who dive with tampons. They are not affected by the pressure as the pressure in all dierections around the tampon is equal. Any air will be vented around the tampon during ascent.

Diving with a Cold

Q. I am just learning to dive, and I know that diving with a cold is not a good practice. I am taking Sudafed for relief of the cold symptoms. My wife is a diver, and only on very rare occasion does she take Prednisone, which has been prescribed by an ENT, who is a diver also. My question is, is it safe for me to take Prednisone to get through my class, or do I need to see a physician first?
A. You risk getting an ear squeeze if you dive with an upper respiratory infection. If you can use enough decongestant to avoid ear and sinus squeeze, the cold will not cause any other problems. You should be aware that you will likely infect the whole class because of the close contact with other students in the training course. Prednisone is used to treat congestion due to allergies, it is not a good thing to take when you have an active viral infection.

Motion Sickness while Diving

Q. I have just become certified in diving but have had problems with my ears for the last 5 years. When I am submerged, water gushes into my ears and I get severe motion sickness. It is so bad that in sports, sweat entering my ears causes motion sickness. I have had CT scans etc, antibiotics, but nobody has found a cause, so I have been looking for an expert. I have tried special earplugs with tiny holes at shallow depths but even they don't keep the water out. This was never a problem as a child, water stayed out of my ears. One time it took 2-3 months for one ear to "pop" and I was in a lot of discomfort that whole time.
A. It is difficult to determine the status of your ears based on your description. You may have a perforated eardrum which would allow water to enter the middle ear and cause cold stimulation of the balance mechanism. This would result in vertigo. The water in the middle ear would also cause a middle ear infection that would require antibiotics, and take several days to clear. You could also have a round window rupture that would cause a rushing sensation and the feeling of motion sickness. You should have an examination by an Ear Nose and Throat specialist to determine if you have a perforated eardrum, and to test your round window function.

Perforated ear drum and diving

Q. I recently suffered a perforated eardrum secondary to an otitis media. The tympanic membrane has never closed and there remains a small hole at the bottom part of the membrane. My ENT physician is unfamiliar with dive medicine. He is recommending that I have tympanoplasty and then wait six months to one year before diving. I understand that there are options available for a person to still dive with a perforation...one of them being the Pro Plugs. I understand, also, that these are not an alternative to tympanoplasty itself which I need to have eventually. Is it safe to use ear plugs while diving with a perforation?
A. A perforated ear drum should be repaired to prevent middle ear infections from even small amounts of water getting through the perforation. Diving with a perforation will always force water into the middle ear and cause an infection. Tympanoplasty will repair the perforation, but after the surgery, there is no guarantee that you would not perforate again. There are divers who returned to diving after a tympanoplasty. After the surgery, you must be able to equalize easily so that there is minimal stress on the patch. There are some products coming on the market that may help. Check out www.proear2000.com. This product is a mask with ear covers that are vented into the mask. It prevents water from getting into the middle ear. Even with a small perforation after surgery, the ears would remain dry, and infection risk would be low. The earplugs I have seen for diving (Proplug is one example) have a small hole that allows some water to get into the external canal to equalize the compressed air volume. These may be OK with a perforated eardrum because you would equalize your external ear canal through the perforated ear drum, and your ear would remain dry. This would not be the case if the tympanoplasty was closed.

Updted 5/27/00


Q. My girlfriend has had numerous surgeries for tube in her ears. She does have severe pain after flying. We assume that she has scar tissue blocking the [Eustachian] tubes, thus not allowing the pressure to escape. I am afraid she will have the same problems if she tries to dive. Is there a way we can find out before she attempts it? We have tried antihistamines, etc. with little or no results. I would really appreciate any help you could give
A. If your friend has tubes in her ears, I take that to mean that she has tubes inserted into the middle ear through the ear drums to help drain the middle ears. This is done when the Eustachian tubes are blocked or when there is recurrent middle ear infection that does not heal because of the chronic swelling and blocked Eustachian tubes. If she has tubes inserted through the eardrums, she has a direct passage from the external ear canal to the middle ear, and water will enter the middle ear if she submerges her head. This will cause another infection. Diving with tubes in the ears is not recommended because of the near certain infections which will occur from contaminated water getting into the middle ear through the tubes. She must have intact eardrums to dive.


Q. I have just been certified in diving but have had problems with my ears for the last 5 years. I use to free dive a lot in rivers and pools as a kid and never had any problems except a few ear infections. My last free dives were about 5 years ago at depths of 10 to 20 feet and I would get a sharp pain between my eyes at any depth over 5 feet. Now water gushes into my ears any time I am submerged and I get motion sickness. What is causing water to enter my ears now? I have had cat scans etc, antibiotics, but nobody helps me. I have tried special earplugs with tiny holes at shallow depths but even they don't keep the water out. This was never a problem as a child, water stayed out of my ears.
A. It is difficult to determine the status of your ears based on your description. You may have a perforated eardrum that would allow water to enter the middle ear and cause cold stimulation of the balance mechanism. This would result in vertigo. The water in the middle ear would also cause a middle ear infection that would require antibiotics, and take several days to clear. You could also have a round window rupture which would cause a rushing sensation and the feeling of motion sickness. You should have an examination by an Ear Nose and Throat specialist to determine if you have a perforated eardrum, and to test your round window function.


Q. I have been diving for 1.5 years and just found out I have allergies. I went to a Nurse Practioner for what I thought was an ear infection that occurred after diving. She told me my ears were fine but that my nasal passages were swollen, blockage of the middle ear, and the ear ache. I have experienced ear infections on 2 other occasions immediately after diving and was given antibiotics. She prescribed Flonase and Allegra-D 1-2 hours prior to diving. I know that taking decongestants prior to diving is dangerous due to them wearing off underwater and causing a reverse block and that Allegra-D is a decongestant, but is taking Flonase prior to diving dangerous? Also, if I didn't take any medication prior to diving and was able to equalize would it be ok to dive this way? Finally, she told me the area were we live is particularly bad for allergies. What warmer parts of the country would be better?
A. No need to move from your area to avoid allergies. Allergies occur all over the world, and if you moved, you likely would develop allergies to other stimuli. The swollen nasal passages can lead to nasal polyps and chronic obstruction of ears and sinuses. Middle ear infections can occur from obstructed Eustachian tubes. The allergies are likely to cause the obstruction. If the Eustachian tubes are blocked, you will have difficulty in clearing your ears and will experience middle ear barotrauma. You should be treated with an antiinflamatory medication, and Flonase is a good choice. You can also tolerate a small amount of a decongestant such as Sudafed taken by mouth an hour before diving. There is minimal rebound from this combination of medication. If your allergies do not clear, you might consult with an allergist for further treatment and possible desensitization. If you can clear your ears and sinuses with the allergies, diving would be possible, but I suggest that you try to control the allergies and reduce the nasal congestion before diving.


Q. Why does my skin break out in angry, red, sore welts when I dive in freshwater? I wear a 5/3 full wetsuit and only seem to have the problem when I dive in freshwater.
A. You are describing something called urticaria or hives. This is an allergic reaction to something. You can get the reaction from skin contact, from eating foods, from breathing pollen or dust. You could react to something on the suit. Soaps, powders, algae in the water, or small organisms in the water could cause the reaction. In some lakes in the midwest there is something called Swimmers Itch caused by small organisms that burrow into the skin. These would be present in lakes where there are a lot of snails on the bottom. You could also get hives from foods you eat, and from pollen. Check all of these things to determine if there is an allergen you are contacting. You might need to consult an allergist and be tested to determine what you are allergic to.

Update 8/20/99


Q. Can I dive while taking a blood pressure medication called an ACE inhibitor?
A. There is no effect of the angiotensin converting enzyme (ACE) inhibitors on diving. These drugs are frequently used antihypertensive drugs that have minimal side effects. They do have one important side effect that must be remembered. In about 15% of people using these drugs, a chronic cough develops about 3 weeks after starting the medication. You should maintain good physical condition, and a periodic treadmill test (every 3-4 years) would assure you that your exercise was being done safely. My advice would be to dive conservatively, keeping well within the no-D limits. There are no data to indicate that hypertension increases the risk of decompression sickness.


Q. I have been diving for eight years and recently had a pulmonary embolism. Treatment in the hospital with Heparin, my scans and x-rays were clear. The suspected culprit was estrogen hormone that I was taking in birth control medication. I am on Coumadin and have a monthly blood test. Will a pulmonary stress test be sufficient to determine if I can return to diving? Will the coumadin have any impact on my diving.[This is a disorder caused by blood clots in the lung. It is treated with blood thinners_FB]
A. Healing from a pulmonary embolism usually requires 4-6 months to reach full recovery. Blood clots likely arise in the leg veins with this type of disorder, and long air flights are usually not recommended until there is a full recovery. The 4 months of recovery time is a bit short to be certain that no residual injury remains. Diving with coumadin is addressed on the scubamed web site. Concern is for hemorrhage into the middle ear and sinuses if a squeeze occurs. Ears and sinuses must be easily cleared, or there is a risk for bleeding into these spaces. You need to avoid traumatic injury as well because of the risk for bleeding. An exercise stress test should be done to be certain that you are physically fit for diving. You should be able to reach stage 4 of a Bruce protocol, or about 12 minutes. A pulmonary exercise test may not be needed to test your capacity, but if available will provide additional information on physical fitness.


Q. I recently was diagnosed with Atrial Fibrillation. Can I continue to dive with this problem? what about the blood thinner used for treatment?
A. Atrial Fibrillation is a common malady among people from teens to the 90's. There are many people with no evident heart disease who develop afib. Acute bronchitis, a bit too much alcohol ("holiday heart"), asthma attacks, flu, sleep apnea, hypertension, overactive thyroid, chronic lung disease, heart failure, abnormal heart valves, congenital heart disease and coronary disease all seem to provoke afib. Colas, chocolate, coffee, tea, and ephedrine (and some of the natural medicines) also can cause afib. Afib can cause strokes by allowing blood to clot in the abnormally beating atria of the heart. There is some controversy about anticoagulants. Data from clinical trials indicate that for people with afib over age 60, or with documented heart disease, the stroke rate is about 7% annually. The use of coumadin reduces strokes to about 1.5% annually, and aspirin alone reduces strokes to about 3% annually. The presence of afib alone is not a contraindication to diving if the heart is otherwise normal, and the heart rate is well controlled. Medications used to treat afib do not affect diving, but ear or sinus squeeze can cause excess bleeding.