The safe use of medication during freediving

Freediving and medication

The safe use of medication during freediving is surrounded by much conflicting advice and misinformation. Sadly a significant number of doctors and specialists know little or nothing about the relation between medication and scuba diving and even less know anything about the relation between medication and freediving. It is not part of the standard education of medically trained people and although new information keeps coming out all the time the subject seems too specific for most of them: so ask a second opinion if you are uncertain you received the right advice. This article is intended to give only a short overview based on experiences and information found about the subject and since I am no expert in this field, nor a physician and a lot is not researched enough yet, I can not guarantee completeness nor correctness of the given information. Therefore no responsibility can be accepted for any harm, injury or fatality resulting from the use of this article.

This article has the following structure:


General introduction into medication during freediving

Questions to ask yourself

Examples of unsafe medication during freediving


A specific example: decongestants

Anatomy basics


Possible causes of equalization problems

Some more common remedies of equalization problems

Some tips if you despite all still insist on using decongestants

WARNING: ↑ back to top ↑

This is only a very short article to give some information on a subject on which information is hard to find and is by no means intended to be complete and can even contain inaccuracies, mistakes or wrong information. New findings can also outdate the information. The sources of information used are regarded as reputable by me but the article is not written or reviewed by specialists.

General introduction into medication during freediving ↑ back to top ↑

In general it is not advised to use any kind of medication during diving. The use of medication is advised against or discouraged by all scuba diving medical authorities. Even very common household medication can be dangerous while freediving. There is however a grey area of things that might possibly be used. The risk however is always present. Side effects and other problems with medication are eventually always tested by users of the substances and by analyzing reported problems that become known. Although very extensive testing is done before medication is available to the public, mostly little or no research is done to effects and side effects of medication under water or during freediving conditions. Also be aware that freediving conditions can differ from common scuba diving conditions! This could make medication which is considered safe for scuba diving unsafe for freediving! This means that you always run the risk of being the first to find out if a substance or a combination of them can be harmful or dangerous by suffering the negative consequences.

Also the reality is that even if adverse reactions to a certain medication are rare in healthy people when it is used as directed that is not to say that certain individuals may have an idiosyncratic reaction to the drug and experience undesirable reactions to a drug while most others do not. For this reason alone, one should never use a drug for the first time just before freediving and should make sure to use it long enough to determine that no hypersensitivity to the drug exists.

Near-accidents, accidents, injuries and even deaths have all happened in which medication was the cause or had a contributing role.



When you use medication of any kind and want to go freediving first ask yourself questions like: ↑ back to top ↑

-         do I really feel like freediving right now ?

-         am I really fit to freedive with the medical condition I use the medication for ?

-         would I be able to freedive without the medication ?

-         is it worth taking the risk involved in taking any medication ?

-         have I personally used the drug before and am I certain that I personally do not have any hypersensitivity to the drug so that no idiosyncratic reaction will occur ?

-         is it certain that the medication has no effect on the capabilities to drive a car or operate machinery ?

-         is the medication free from sedative or pain-killing effects ?

-         is the medication free from effects on my physical exercising- or breath hold abilities in a positive or negative way ?

-         is the medication free from effects on blood pressure or blood viscosity ?

-         is the medication free from diuretic effects and other effects on the fluid balance in the body ?


Arguments are based on the following: To freedive safely you need to be fit and fully able to sense everything that is going on in your body in the way you normally do. Because you carry your only oxygen supply in your body, any effects on metabolism, abilities to sense what is happening in your body, abilities to sense low oxygen or alteration of blood flow are unwanted. Also ask yourself the question if, considering the reason you take the medication, you really are fit to freedive and secondly if you are a safe buddy to dive with. Freediving is a stressful sport with no means to escape from a dive that is too long or too deep, so do not stress the body when it might not be able to deal with it fully.

"UNSAFE" medications include for example: ↑ back to top ↑

All medication causing drowsiness (or alter the ability to sense) like for example:

-         pain killers and especially sedative or narcotic pain killers, which thereby combine two undesired effects;

-         most antihistamines & most decongestants (tablets);

-         most motion sickness medication.

This medication increases the negative effects of Nitrogen Narcosis, slows reflexes, impairs judgment and makes it difficult to judge a safe dive time. Pain killers can make a freediver react insufficiently to pressure related pain or numb the senses needed to safely freedive.

Psychiatric medication like for example:

-         antidepressants;

-         sedatives;

-         mood elevators or stabilizers.

With Psychiatric medication, it is not only the side-effects underwater that are important, but also the reason why the medication is used. People who are sensible to mood swings, panic attacks or overconfidence, can thereby endanger themselves and also their buddies. They may also have difficulty sensing their body in a consistent way, needed to freedive safely.

Medication limiting normal responses to exercise or altering the metabolism:

-         certain anti-hypertensives (especially beta-blockers);

-         diet pills which alter metabolism to loose weight;

-         food supplements or a diet that significantly alters the proportions between carbon hydrates/ fat/ protein normally present in the persons food intake.

Limiting normal response to exercise or lowered metabolism prevents optimal performance in an emergency. Increased metabolism or a significantly changed diet makes sensing safe dive time or depth inaccurate. Medication altering heart rate or metabolism could increase chances of developing arrhythmia of the heart during and after freediving.

Medication interfering with the blood pressure, blood viscosity or fluid balance in the body:

-         blood pressure altering substances;

-         blood viscosity altering substances and medication containing acetylsalicylacid (Aspirin)

-         substances that alter blood clothing properties;

-         diuretic pills and substances that have diuretic effects;

-         medication containing alcohol or caffeine;

-         coffee or chocolate just before a dive.

Freediving just by itself puts a lot of stress on the cardio vascular system, just think of bradycardia, peripheral vasoconstriction, vasodilatation in for example the brain, bloodshift, spleen contraction, changes in blood pressure, changing Ph of the blood; every dive again, even shallow ones. Thick blood puts extra strain on the circulation, increases the chance of developing blood cloths and emboli. Blood thinners increase the chance of bleedings and blackouts. Dehydration adversely affects the capability to freedive and thickens the blood. In general freediving is not recommended for people who need this kind of medication.

Also be aware of and avoid medication found relatively safe for scuba diving but that can have an influence on the heart like:

-         antibiotics
Sport and infections, especially ones so severe that medication is used, do not combine and can be dangerous.

-         nasal spray containing substances like Xylometazoline, Oxymetazoline or Tramazoline and pills containing pseudo-ephedrine (pseudo-ephedrine is related to adrenaline) like Sudafed®.
In spay additives and preservatives like
benzalkonium are often used which hurts the cilia which are part of the cilia mucous system which keep your sinuses and ears healthy.
In scuba diving it is advised against diving deeper than 30 meters or using nitrox on Sudafed because it could adversely affect susceptibility to nitrogen narcosis and oxygen poisoning (source: Sudafed should possibly be considered more dangerous in freediving for in freediving it has more negative side effects like decreased bottom time, the heart is under more stress from freediving than from scuba diving and nitrogen-narcosis effects are worst when you descend fast.
If you need decongestants to be able to freedive or have a cold: skip the dive

Decongestants ↑ back to top ↑

Most incidental use of medication in freediving is decongestants. Let us look a little bit more into that subject. Most decongestants rely on substances like Xylometazoline, Oxymetazoline, pseudo-ephedrine which affects the heart and metabolism. Safe bottom times become unpredictable and it might promote all kinds of problems with the heart during freediving. Also the diving medical specialists of the Dutch scuba magazine Duiken ( published that pseudo-ephedrine possibly makes humans more susceptible to both nitrogen narcosis and oxygen convulsions so they advice against deep (30meter) dives for scuba divers. DAN also published slightly different information on this in 1999

These substances are possibly more unsafe for freedivers than for scuba divers because the effects on heart and metabolism are possibly not as important for scuba diving as they are for freedivers.

Anatomy basics ↑ back to top ↑

Let us first look at what the main parts of the body are anyone would want to use decongestants for. The head of a human contains several cavities. The main cavities that can give problems clearing during a dive are the ears (the inner part of the ear) and the sinuses (frontal sinus 2x, maxillary sinus 2x, frontal and back ethmoidian sinuses, sphenoid sinus).

These cavities have important functions in the body and must be air filled and be or be able to open to function normally. All cavities drain into the nasal cavity via their own tiny ducts. The sinus openings to the nasal cavity are usually open and therefore should not require any effort to equalize while the opening to the ear (the Eustachian tube) is usually closed, and requires some effort to equalize on descent. Some sinuses are subdivided into smaller “chambers” with passageways that can clog up too and thereby can cause problems deeper in the sinuses. The nose has a “tidal” function by which breathing is dominantly done by one nostril at a time which alternates every few hours. The lining of the nose, inner ear and sinuses is about the same and an infection or irritation at one point might also be present in other parts of the lining. Together with the nasal membrane the sinuses produce over a liter of mucus and secretions per day when healthy. Irritations (including allergies and infections) can cause the mucus membranes to swell. A by mucus or otherwise sealed up cavity will eventually infect. You can much easier feel if the ear does not equalize properly than with the sinuses because of the greater number of pain receptors present in the areas. The absence of good pain detection in the sinuses means that if you feel a dull pain or pressure in the area of your teeth, cheeks, eyebrows or forehead you might already have gone too far so do not push it. ( + (look under “3D sinus pictures” for a virtual tour along the sinuses)

Equalization ↑ back to top ↑

To be able to dive we need to be able to easily get air in and out of them which is called equalization. When a cavity is obstructed or the passageway is too narrow by whatever cause we cannot get (enough) air into it on descent (clearing) or out of it on ascent (reverse block). If forced too hard this can result in severe injuries, which can be permanent. Do cautious warm-up dives, when you ruin a dive by equalization problems and push chances are diving is over for that day, even before it really started!

When you cannot dive without decongestants you should not freedive, otherwise the risks you take are way too big. Also do not clear forcefully to avoid damage by clearing too forcefully or risking a reverse block on the way back up to the surface.

Possible causes of equalization problems ↑ back to top ↑

1 Technique

The right technique (right action + right timing) of clearing is very important. A nice overview can be found on Use only the techniques of Beance Tubaire Volontaire (BTV) ( or the frenzel maneuver (the frenzel fattah version described in If you can equalize fine up to 10-15 meters but not deeper then consider your technique to be the problem. The techniques sound and look simple but many still do it wrong after reading the article and there are also other tips that might help; so ask a competent freediver to check your technique. My personal experience is that the average scuba diving instructor often has too little knowledge about the subject. Some experts claim that (almost) all people with problems clearing their ears can be helped by learning the right technique. Ask Erik Fattah, the author of the frenzel document or the Solomons ( who among other things teach equalization.

WARNING: never equalize on ascent, especially if you suspect a reverse block.

2 Anatomical abnormalities

If problems persist let an ENT do an examination into anatomical abnormalities. Freediving ENT’s are very scarce but scuba diving ENT’s know a lot too. A list of Dutch ENT’s familiar with scuba diving can be found on or you can contact your local divers alert network ( or try and ask around at forums like An endoscope and tympanometrie is not a complete examination as for that an MRI or CT-scan is also necessary. Use surgery only as an absolutely last resort after you have tried EVERYTHING else ANYONE can think of. Surgery in the head is risky and chances are big it will create another problem, worsen the problem, only help partially or does not help at all.

3 Other (medical) problems

Infections, swollen mucus membranes or excess mucus and secretions can account for huge equalization problems. It is better to attack this kind of problems at the source than resort to medication, which might be adding (other) problems. There can be lots of underlying causes for which personal medical advice is needed. If you irritated something while pushing equalization it might take a long time (2 days up to 6 months) to heal enough to safely freedive again.

Some more common remedies of equalization problems: ↑ back to top ↑

-         Avoid dry air like in airplanes or air-conditioned rooms. Effects can last into the next day.

-         Avoid diesel and other fumes from engines because they impair the cilia movement and give other irritations which can cause equalisation problems.

-         Blow your nose just before diving. Pull it up with a loud and horrible vibrating noise instead of using a handkerchief because you want to get rid of the snot and not push it into places you do not want it to be. Put any scruples aside and try it.

-         Drink enough both before and during diving. A good fluid balance has a positive effect on mucus membranes and your ability to equalize. Hot chicken soup and hot tea are said to be the best for they also are said to stimulate the cilia. Avoid cold drinks if you have a choice. Do not count how much you drink but rather look at the colour of your urine, which should have a very light colour. Because of the moisture loss during heavy breathing and the diuretic effect of the diving reflex you might have to drink during long diving sessions.

-         Avoid cigarette smoke, alcohol (especially red wine), caffeine (coca cola, coffee)

-         Try additional techniques to assist equalizing when you have trouble equalizing the ears like wiggling the jaw, pulling up the soft pallet, make a big mouth like when yawning, wiggle the ears, swallow, ……….

-         Wear a warm cap on your head or a swimmers-cap underneath the hood of your wetsuit. Watch out for hood squeeze which can create severe injuries but can also hinder equalization. You could try to wear a thin rope like that of the well known Paradisia noseclip over your ears or put holes in the hood to “break” the seal of the hood.

-         Avoid cold waters if you can or try a mask which covers a bigger part of the face or try an ice cap like the Henderson Ice Cap ( underneath your hood because cold water can create or aggravate problems. Watch out for the danger of hood squeeze!

-         Stress can give clearing problems too so avoid stress and relax in the water. Especially focus on relaxing everything in the head area.

-         Flushing with salt water according to the Yala Neti technique (,,, is a decongestant itself and can also help to get rid of excess mucus, diminish irritations, and by clearing the nose can facilitate healing of infections in the long run. Depending on the problem for an optimum effect you might have to start doing Yala Neti many days before diving.

-         With sinus trouble rub up and down along the nose and across the eyebrows for a while and relax those areas. Sometimes swimming hard with the face out of the water to get the blood flowing there might save the dive. Do gentle warm-up dives without pushing anything, preferably “free immersion style” ( which gives best control over depth.

-         Many problems result from inflamed lining tissue in which case anti-inflammatory can help. A non-steroidal anti-inflammatory is ibuprofen (Advil). Some swear by a combination of papaya and pineapple enzymes in pill form as a natural anti-inflammatory. Be aware that non-steroidal anti-inflammatory drugs can harm your stomach and that they often work as a painkiller, which is unwanted for freediving.

-         According to some Proteolytic Enzymes can be very effective against equalization problems with both ears and sinuses and quite safe as long as you are not allergic to them or the plant they may be derived from. However it is claimed you have to be careful about where you get them from and how you use them (

-         Polyps can appear suddenly and grow fast. A doctor should check if you have any.

-         A tendency towards swelling of mucus membranes in the whole body has been observed in women around the period of menstruation and/ or ovulation. This could perhaps negatively affect equalization during those periods.

-         Take an allergy test for substances that can be in the air and also in food. Ask your doctor if there are substances you should avoid. Almost any substance can potentially cause a reaction in an individual so investigate what YOU react too before trying out all kinds of diets advised by others. Milk, nuts, wheat and sugar are often suspicious foods.

-         If you are tested and allergies are detected, medication against the allergy may help more than taking decongestants (

-         Try a “ProEar Mask” ( and see if keeping (cold) water away from the ears helps equalizing the ears to solve or better locate the problem.

-         I would not advise it but I learned that someone put Vaseline in his ears to keep out the cold water, which helped him to be able to equalize.

-         Try descending feet first instead of head down to see if this helps.

If you despite all still insist on using decongestants ↑ back to top ↑

If used in a competition, be aware that many substances are considered cheating or dangerous and therefore are on a doping list.

Minimize the use of medication to an absolute minimum so that there is at least as less as possible in your system during freediving according to 3 strategies you can consult with your doctor.

1.      use medication or alternative therapy (like Yala Neti) that can be (best) combined with freediving or can reduce the need for other more unsafe medication;

2.      use as less as possible of the medication, find the lowest dose that works;

3.      time the use in regard to the moment you will do your dives so you have as less as possible in your system at the moment of freediving.

Anti allergy pills often work long term and slow so you might be able skip a dose before freediving or take that dose immediately after freediving.

Nasal spray containing Xylometazoline, Oxymetazoline, Tramazoline and many over-the-counter nasal sprays work only on short term (and as a side effect can even give a rebound effect causing greater congestion) so you might limit it to taking only a very small dose just an hour before starting to dive.

Decongestant tablets sometimes have their optimum effect for diving when the level of active ingredient is already for the biggest portion expelled from your system (your pharmacy or doctor will have information on this) so it is possibly the best to take them quite some time before diving (the evening before?).

I hope the information is useful, please let me know. I cannot give any individual medical advice nor can I guarantee the correctness of the given information because a lot of research still needs to be done, I am no expert in all the necessary fields, I am not even a qualified physician. Use the information on your own risk and do not take my word for it. This information does not replace personal medical advice; it is just an aid for you and your doctor to discuss what might suit you best. Always remember that it is your body and not someone else’s so be careful with it.

© R. van den Akker, 7-2004

Copyright reserved. The author can be reached through the owner of this website (

Update: 28 July 2004 Copyright / Hoofdpagina / Sitemap / Contact