Now, I have spent considerable effort in order for you to understand how pressure and oxygen concentration play a role in determining the actual treatment potential. In fact, I have used the words "potential tissue oxygenation increase" a few times. The reason for the term "potential" is because we still have another variable to consider... Duration! Just because we have a gradient and diffusion is taking place, doesn't mean the process occurs immediately. The rate of diffusion and achievement of the total treatment potential is dependent on the tissue, its vascularity, density, and degree of edema present.
Don't worry, we're not about to get started with another arithmetic assignment; but it is important to understand how duration of treatment plays a role, and how this variable can be manipulated in order to achieve ideal results.
Common treatment times range from forty-five to ninety minutes; however, research has demonstrated benefits in as little as twenty minutes of therapy at treatment pressures as low as 1.1 ata (I can't honestly tell you if it is a true 1.1 ATA, or if they simply pressurized a chamber 1.47 psig and called it 1.1 ata). Case studies have shown the ability to interrupt migraines with low pressure chambers in around the same time. Further, a relaxation response can generally be seen within the first ten minutes of treatment. Generally the greater the pressure and higher the oxygen concentration, the faster this response can be seen. On the other end of the spectrum, many athletes are known to spend the entire evening in mild portable chambers to help aid in recovery from training and speed the rate of healing and repair from injury.
So what is the ideal duration? Is sixty minutes the ideal duration? Maybe if you are looking to run sessions on the hour. Sixty or ninety minute sessions surely makes it easier for offices to schedule appointments and track sessions, but other than convenient scheduling what makes these durations so special? Why not eighty-five or one hundred minutes? Fact is, if you asked a clinic why not eighty-five or one-hundred minutes... they might try to justify their selected duration with a statement pointing towards the latest research; but then you have to ask... why did the research group do ninety minutes and not eighty five or even one hundred? The point I am trying to illustrate here is that very little thought actually goes into the duration of treatment, especially when considering the mild hyperbaric community. Basically, the recommendations that are handed down from practitioner to patient are broad generalizations with little consideration to what is actually occurring. Some conditions may actually benefit from a longer treatment, while others may only get tiny residual benefit from additional time. My goal is to set down some guidelines to help both the practitioner and patient select a treatment duration that is right for them.
Basically, there are a number of factors we need to consider. Upon consideration of these factors it will become quite clear in regards to the amount of time (at least a ball park figure) you should be spending in the chamber. These factors include: your condition, treatment pressure & oxygen concentration, and your personal schedule and availability.
First and foremost, what is the main objective for undergoing mild hyperbaric treatment. In other words, what condition or type of condition will you be treating. Is it an injury? If so, what type of injury? Is it infectious? If so, is it gastrointestinal, sinus, or maybe bronchial? The reason we want to consider the condition is because different types of tissues take longer for hyperbaric effects to take place. Blood is mostly water and becomes saturated quite quick, but fatty tissues, less vascular tissues, and dense tissue take longer for saturation to occur. For example, ligaments are very dense and have virtually no vascularity; as a result, longer durations suit these tissues. Intervertebral discs are also avascular, however they are not as dense (more of a jelly like structure). These structures take longer than non-fatty vascular tissues, but not as long as ligaments and tendons. The brain however is composed almost entirely of fat, yet it is extremely vascular. Due to its vascularity the brain benefits moderately quick, but not as quick as vascular muscle tissue which is one of the fastest tissues to allow gases to diffuse in and out of.
One last thing to think about while considering different conditions is the point of little residual gain. At a certain point (duration) you aren't getting much benefit for your otherwise valuable time. Consider a sliding scale over four hours in which at zero minutes you have 0% benefit, and at four hours you have reached 100% benefit for every tissue in the body. In forty-five minutes you may be at 50% of your total potential benefit for that treatment. In the next forty-five minutes (ninety minutes total), you may only gain another 25% benefit; bringing you to a 75% total. And yes, if you stayed another forty-five minutes you might only be another 12.5% further towards 100%. This residual gain is what is referred to as half-times. In a certain amount of time, 50% of a gas will diffuse into a tissue. Obviously different tissues have different half times based on the factors we discussed above; density, vascularity, adipose content, etc.. Point being, the major benefits are achieved in the earlier minutes and with each passing minute the treatment continues to work deeper into tissues, continuing to raise tissue oxygen levels further towards equilibrium. The reason I had stated zero to four hours is because four hours is the point every tissue has reached its max potential for any given concentration gradient. Of course higher pressures and higher oxygen concentrations would have increased tissue oxygenation levels greater than lower ones, but regardless of the pressure and/or oxygen concentration, what's done is done at this point in time (or duration if you will).
So, with an understanding of half-times, residual gain, and some basic knowledge about the various tissues, we can put a couple of parameters out. Generally, more than two hours is never called for. The only time a treatment longer than two hours is truly necessary would be the acute phase of decompression sickness, and you shouldn't be treating that with a portable mild hyperbaric chamber to begin with! On the short side of things, I personally believe that even ten minutes at pressure can be of benefit for many conditions when we consider the importance of frequency (to be discussed in next section). The cases that I don't perceive such a short treatment being of benefit for would be treating sports injuries, post-surgery indications, etc. Anytime we get into these low vascular tissues, we are really going to want to shoot for the longer times and probably not less than forty minutes. Now I know I just recently mentioned a ten minute treatment; please don't even begin to think that I am recommending a treatment protocol of ten minutes. Without diving too deep into the next section on frequency, let's just say something is better than nothing! Generally, most treatments are going to range between forty-five to ninety minutes with sixty probably being the most popular. We still have a few more things to discuss in regards to duration, but hopefully you are beginning to understand that there is no exact science that is going into the recommendations that are prescribed across the nation. Instead, the recommended duration is more or less a best guess! Like I said before, just go ahead and ask how the duration time of 60 or maybe 90 minutes was "calculated". Trust me, the so called "advanced and individualized protocols" that some physicians claim to offer, are little more than cookie cutter approaches.
Okay, now let's look at a couple other factors concerning duration! When considering mild hyperbaric (< 1.5 ata) and the available equipment, treatment pressure and oxygen concentration are not as a large of concern as compared to working with pressure ranges capable in a more clinical arena (>1.5 ata -6 ata). In the clinical deep hyperbaric arena, especially when working with 100% oxygen above 2.0 ata, the practitioner must be very concerned about oxygen toxicity. In fact, regular air breaks are scheduled at every twenty to thirty minutes of treatment. During these air breaks the patient breathes 21% ambient air instead of 100% oxygen. The purpose of this is to lower the oxgyen saturation in tissues such as the brain to prevent the occurrence of oxygen toxicity and a potential oxygen seizure. Yes, too much of a good thing can be harmful. In fact, research has demonstrated that lower pressures have been superior in treating neurological conditions and it is postulated that high pressures and oxygen concentrations become counter-productive as oxygen tolerance thresholds (oxygen toxicity thresholds) are met. A pressure of 2 ata w/ 100% oxygen is nearly a 500% potential increase in tissue saturation, no tissue in the human body needs this much oxygen; however, such an increase in oxygen creates an incredible concentration gradient making it possible to get increases of 50-100% deep into the slow saturating tissues such as bone and ligament in reasonable amounts of time. I say "reasonable" because those amounts could be achieved at lower pressures with longer durations. However, it is cost prohibitive in the clinic/hospital to provide such time-intensive treatment. On the other hand, mild hyperbaric is fast becoming popular as a home treatment. In the home, a thirty minute session costs the same as a two hour session. As a result, similar benefits of a higher pressure can be achieved by utilizing longer duration treatments. For example, if O2 concentrations are equal; two hours at 1.3 ata is about equal to sixty minutes at 1.5 ata. The reason of course is because in sixty minutes one has not fully capitalized on the benefits of any given pressure, yet in two hours... the majority of benefits will have been achieved. To put it another way, maximizing the benefits of a lower pressure through longer duration exposures can be very similar to the benefits achieved from slightly higher pressures that have only been marginally capitalized upon.
Now, here comes the flipside of duration in regards to tissue saturation; the longer one spends at pressure, the more time post treatment in which tissues will remain in a raised oxygenated state. Yes, the higher oxygen levels do not immediately disappear post treatment; rather the slower the tissue to saturate, the longer they remain saturated. This means the blood goes back to its normal state rather quick; in a matter of minutes... but the brain, joints, and other tissues of the body all remain in greater oxygenated states until either the excess oxygen diffuses back out or it is metabolized via the tissue. So, highly metabolic tissue will use it up quicker versus your ligaments which will hold on longer!
Another benefit to longer sessions actually doesn't have to do with oxygen at all. Another benefit of hyperbaric therapy is the reduction of edema. Just as we apply pressure to injuries to help control inflammation and edema, hyperbaric is applying pressure to your entire body. This total body compression helps to move excess fluids out of the extracellular spaces and into lymphatic tissue where it can be cleaned up, brought back to the blood stream, and then excreted from the body after being filtered out via the kidneys (the main reason I always recommend using the restroom prior to beginning a session). Generally, after a few consistent sessions of hyperbaric therapy, unless a serious edemic condition exists, patients don't need to run for the bathroom after sixty to ninety minutes.
Now we should consider one more component; not such a scientific one, all be it very important... your schedule. Like all forms of therapy and self improvement, a certain degree of commitment must be made on the part of the patient and potentially on behalf of family and/or friends who may be necessary in the facilitation of the treatment. Remember that hyperbaric therapy is not an all or none treatment, but more of a sliding scale. We need to move away from the "absolute" mentality when undergoing hyperbaric therapy. If your program calls for ninety minutes per day and some days you can only possibly get sixty-five minutes in; then just do sixty-five minutes. Definitely don't skip the treatment just because you couldn't do the full ninety. We have to be realistic of what we are capable of, yet at the same time, understand that we don't have to hold ourselves so rigid in relation to our therapy program. Of course I am not suggesting to just throw out the recommendations of your practitioner; rather I am suggesting you be honest with yourself and your physician about what you can accomplish. If it isn't feasible, then you need to find something that is. Most importantly, you need to believe that your compensated program will be just as successful. Whether a therapy actually works or simply your belief in a therapy caused a placebo benefit; in the end you achieved results. The worst thing you can do is to undergo a therapy program with the belief that it won't be successful. Constantly second guessing a therapy program because you aren't able to carry it out exactly as was prescribed is a message to your subconscious that the program won't work. The point I am trying to make is the same point that has been being driven home for a number of pages; this is not an exact science and success in your recovery will not come from one factor, but a number of factors... the most important of which we will discuss next.
Part 5: The Importance of Frequency
About the Author: Greg Harris is the founder of Hyperbaric Options LLC and has spoken publicly about health & wellness in various settings over the past eight years. Greg has a passion for human potential and is a firm believer that nearly all of the health problems we face today, from degenerative neurological conditions to the common cold, are preventable and reversible. As a health professional, Greg has a unique ability to connect the dots where others have left them scattered; it is this ability to integrate disciplines and think outside of the box that give his lectures and written materials a fresh point of view.
Disclaimer: The information and advice published or made available throughout this article is not intended to replace the services of a physician, nor does it constitute a doctor-patient relationship. Information contained within the following and/or preceding pages is provided for informational purposes only and is not a substitute for professional medical advice. The author encourages all readers to further research any topics of interest and reminds the reader that the comments and materials being presented do not necessarily constitute scientific fact and may contain opinions, theories, and third party views not widely accepted. You should not use the information contained in this published material for diagnosing or treating a medical or health condition. You should consult a physician in all matters relating to your health, and particularly in respect to any symptoms that may require diagnosis or medical attention. Any action on your part in response to the information provided throughout the material is at the reader's discretion. Readers should consult their own physicians concerning the information in this material. Hyperbaric Options LLC is not liable for any direct or indirect claim, loss or damage resulting from use of this material.