Respiratory Muscle Training for Swimming, Diving, and Running

The previous post on training breathing muscles -
Respiratory Muscle Training for Better Health and Exercise - covered how breathing exercises have been found to help increase respiratory capacity in people with various diseases, and more recently, to help physical training in athletes. At the diving and hyperbaric conference three weeks ago, I attended sessions on respiratory muscle training for underwater operations. It is a topic of interest for those in charge of combat swimmers.

In one study, Researchers at the State University of Buffalo at New York found that respiratory muscle training improves swimming and respiratory performance at depth. As you go deeper, the work of breathing can increase, even using high performance breathing devices, because of higher gas density and other factors. They tested the effect of resistance respiratory muscle training on respiratory function and swimming endurance in divers at 55 fsw (~16 m). They found that respiratory muscles were less fatigued following training, breathing rate was lower during the swims, and that the training increased the duration they could swim by about 60%. They concluded that respiratory muscle fatigue limits swimming endurance at depth, and the increase in swimming endurance may result from reduced work of breathing or improved respiratory muscle ability.

The second study by the same group looked at the different benefits of training the endurance and strength of the respiratory muscles. Eighteen SCUBA-certified swimmers were randomly assigned to a placebo group who didn't train their breathing muscles, a respiratory endurance training group, or a respiratory strength training group. Each group used a breathing resistance device five days a week for 30 min over four weeks. The endurance trained group decreased heart rate and ventilation during underwater swims. Both the endurance and strength groups improved fin swimming endurance. The placebo group experienced no changes.

The researchers concluded that respiratory muscle training is effective in improving swimming endurance. They told me they found it is also effective for endurance running, but perhaps not as effective. They are working on finding out why. My friends who do long stints in submarines mentioned they like to use respiratory muscle training to help keep them in shape since they can't go out for a run while on sub duty.

The post Do Breathing Exercises Work? shows ways to try breathing training. The book Healthy Martial Arts gives more.

Labels: aerobic, breathing, endurance, hyperbaric, performance enhancing modality, scuba, strength, swimming

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Does Hyperbaric Treatment Help Muscle Injuries?

The previous post Does Hyperbaric Treatment Heal Sprains? covered research that looked into hyperbaric oxygen treatment for injuries like ankle and knee sprains, and muscle soreness.

Some professional sports teams have been using hyperbaric oxygen chambers hoping to speed recovery and enhance performance. Players spend time in a small pressurized enclosure, breathing high levels of oxygen. Other athletes and private citizens have purchased chambers, hoping for various gains. Like other helpful and specific medicines, hyperbaric oxygen helps some things and not others, and can have side effects. The post Does Hyperbaric Oxygen Help Exercise Ability? explains more of how it works.

Sprains and delayed onset soreness are not injuries where low oxygen prevents cells from doing their job to fight infection and rebuild. Elevating oxygen levels doesn't turn normal cells into super cells. It returns them to function. For non-geriatric athletes, sports injuries should not be hypoxic, which is an area of low oxygen. (Given the junk these athletes eat for "sports food" the state of their blood vessels should benefit by a closer look. See Is Your Health Food Unhealthful.)

A concern in hyperbaric medicine is that sensationalized use of hyperbarics for things that may not work will take the legitimate medicine of oxygen treatment and give it a sham image. Dr. Steve Thom, MD, PhD, past president of the Undersea and Hyperbaric Medical Society (UHMS) warns that some team physicians appear unaware of the risks of hyperbaric medicine. He stresses the need for proper medical clearance and supervision of the hyperbaric chamber. For certification and policy information, see the UHMS web site.

The idea that perhaps there are other effects of injury that are not from low oxygen has led to more research on sprains and muscle injury. A study presented here at the UHMS meeting this week by a group from the Tokyo Medical and Dental University in Japan was, "The effects of hyperbaric oxygen therapy on patients with muscle injury." They wondered if hyperbaric oxygen could reduce edema after muscle injury.

Dr. Kazuyoshi Yagishita and colleagues looked at twenty patients who sustained muscle injury during sports, who were admitted to the Tokyo hospital within seven days after injury. The patients received hour-long hyperbaric treatments for one to seven sessions. Patients were tested before and after each treatment for pain at rest and with motion, subjective evaluation of edema, muscle stiffness, and leg volume. All parameters slightly improved with treatment. They concluded that, in this study, in patients with muscle injury, hyperbaric treatment was effective. Dr. Yagishita told me he felt that further study is necessary to assess healing acceleration and intermediate and long-term results.

Labels: hyperbaric, injury, performance enhancing modality, sprain

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Does Hyperbaric Treatment Heal Sprains?

The Utah Deseret News reported on a game where teens scratched letters into their arms. In March, a 14-year-old girl playing the game became infected with necrotizing fasciitis, commonly called "flesh-eating bacteria."

The bacteria don't eat the skin as the name seems to say, but release toxic factors, which quickly destroy skin and muscle, causing pain, disfigurement, and a high death rate. Necrotizing fasciitis is a serious infection. The teen needed over 60 hyperbaric treatments and several surgeries. Hyperbaric oxygen treatment is done in a small room or chamber. The air pressure inside is increased so that the person can receive more oxygen. One or more people can get treatment in the chamber at once. The post Does Hyperbaric Oxygen Help Exercise Ability? explains more of how it works.

Hyperbaric oxygen treatment is effective against necrotizing fasciitis and infections like gangrene in several ways. The bacteria involved are susceptible to high oxygen pressure, the low oxygen area of the infection is raised to a level where the body's white cells can do their job to clear the bacteria, higher oxygen pressure prevents white cells from sticking to vessel lining, and a few other nice effects to be covered in future posts.

Given that hyperbaric oxygen speeds healing in certain infections, crush injuries, problem wounds, diabetic ulcers, thermal burns, ionizing radiation injury, refractory osteomyelitis, osteoradionecrosis, and compromised grafts, it has been hoped by some that it would also be useful for sprains and muscle injury.

One study by diving medicine pioneer Dr. Fred Bove (my advisor for one of my dissertations) and his colleagues, found no effect of hyperbaric oxygen treatment on time to recovery for ankle sprains (Am J Sports Med. 1997 Sep-Oct;25(5):619-25). Another study by Dr. Michael Bennett and colleagues reviewed known past studies using randomized trials of hyperbaric oxygen on soft tissue injury (ankle sprain and medial collateral knee ligament injury) and muscle soreness after exercise. They found there was was not enough evidence that hyperbaric treatment helped ankle sprain, acute knee ligament injury, or soreness (Cochrane Database Syst Rev. 2005 Oct 19;(4)). Dr. Brad Bailey of San Diego did a review of the utility of hyperbaric oxygen for sprains and sports injuries and found no benefit for soreness, but a few studies that showed benefit in acute sprains and strains. There may be aspects of injury, not previously looked at, that may be helped. These are being looked at in newer studies. The next post will cover them.

You can do much to rehab sprains on your own. Posts with helpful information to prevent and rehab sprains are:
How To Treat Ankle Sprains and Prevent Them
and
No More Ankle Sprains Part II.

Labels: hyperbaric, injury, performance enhancing modality, soreness, sprain

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Exercise and Fitness in Decompression Sickness Risk

In the post Train Exercise is Exercise Training I mentioned the ongoing question in diving physiology research of how exercise can affect the risk of decompression sickness (the bends).

It seems that exercise done during a scuba dive at the bottom increases the amount of nitrogen gas you absorb from the air you breathe from your tanks. This makes more gas which could contribute to decompression sickness on the way up. Mild exercise on a "decompression hang" (waiting at specific shallower depths for a few minutes on the way up) seems to help let more gas dissolve out while you breathe, and may lower risk. Exercise soon after surfacing may increase gas coming out and increase risk according to other work. Some interesting studies look into whether exercise done days before a dive can reduce risk by "using up" specific components that decompression sickness bubbles need to be able to form. The kind of exercise and timing seems important. I will post more on this another time.

Some work looks at physical fitness, and whether that affects risk of decompression sickness (DCS). Would someone in better physical shape have lowered risk? What constitutes being in better shape? Is it body fat? Is it the amount of oxygen you can use to exercise? How might any one of those components affect DCS risk?

Here at the UHMS scientific meeting, one of the studies presented by French naval researchers is, "Does the VO2 max value predict the formation of intravascular circulating bubbles during decompression of healthy divers?" VO2 max (pronounced vee-oh-too-max) is the most oxygen you can use when doing the most exercise you can do. It is usually higher in people who can do more aerobic exercise (other factors also contribute). The maximum amount of exercise an average person can do is about ten times their resting level of oxygen use. Marathoners usually max at around 20 times better than resting levels. A top aerobic athlete can use about 30 times resting level (a horse - more than twice the top human max). Someone badly out of shape, or with heart disease or other problems that limit ability to get oxygen to cells, generally has a low VO2 max. You can raise your level with regular exercise at any age. It is not set.

In the French study, divers were tested for VO2 max a week before their experimental dive. They avoided any physical exercise 48 hours before the dive. Then half completed a dive in a dry hyperbaric chamber and the other half in the open sea with the same dive profile and decompression stop according to French military decompression table MN90. After the dive they were all tested for presence of small decompression bubbles in the bloodstream.

Bubbles can form in the body painlessly after a dive without creating decompression sickness. It is not the case that bubbles always form after every dive, as often thought. Certain bubbles can be detected audibly (they sound like pops and squeeks) using Doppler ultrasound, and other kinds of instruments being developed. I will post more another time about these bubbles and what ultrasound can and can't determine about bubbles and decompression sickness.

The French researchers found that bubble formation in both types of dive was related to the age and body mass index of the divers, but not to VO2max.

Being in good shape makes many aspects of diving safer, even if it doesn't affect risk of decompression sickness. Being in better aerobic shape helps you swim more easily against currents that may take you away from your dive site or boat. Strengthening your body through weightlifting with good body mechanics helps you lift and haul gear with less chance of injury, and practicing all your physical skills helps you be more able to rescue someone or yourself.

What about physical fitness and risk of decompression sickness in space? Several studies here at the meeting address that. Astronauts who go outside the space vehicle go to lower pressures, similar to divers coming up from a dive. Many considerations, including exercise, go into their preparation for that. The interesting story is posted in Space Walks.

Labels: aerobic, aerospace, hyperbaric, scuba

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Hyperbarics for Diabetic Foot Injury

It is estimated that every 30 seconds someone in the world has their foot amputated because of a diabetic foot ulcer. Reduced blood supply to the feet and lower legs in people with diabetes delays wound healing and increases infection and chance of gangrene. Foot infection worsens the situation of inadequate blood supply by increasing the area's need for oxygen but decreasing blood supply. Poor blood supply further decreases ability to fight infection. Diabetic ulcers treated with antibiotics can become colonized with drug-resistant bugs.

I am at the annual meeting of the Undersea and Hyperbaric Medical Society (UHMS). Several interesting studies are being presented on diabetic wound healing. Enhancement of healing in selected problem wounds is one of the 13 approved indications for use of hyperbaric oxygen therapy as defined by the Hyperbaric Oxygen Therapy Committee. Hyperbaric treatments are done by putting the entire person in a small room or chamber and increasing the pressure inside so that the person breathes oxygen at higher pressure than what you are breathing now. The post Does Hyperbaric Oxygen Help Exercise Ability? explains more of how it works.

One of the studies presented here looked at 50 patients with severe diabetic foot ulcers. Half were treated with hyperbaric oxygen therapy (age and gender matched with the half who did not). Diabetic patients treated with hyperbaric oxygen had 56% chance of healing and 16% chance of amputation. Diabetic patients not receiving hyperbaric oxygen therapy had a 32% chance of healing and a 32% chance of amputation. Supplying oxygen to compromised areas, such as diabetic wounds, is important to restoring health. Hyperbaric oxygen is established to help that.

From the President's Competition came another study on hyperbaric oxygen therapy and stem cell mobilization in people with diabetes. This study was by researchers at the University of Pennsylvania's Institute for Environmental Medicine, where I did nine years of my research in diving medicine. Hyperbaric oxygen is already known to mobilize bone marrow stem cells in animals, healthy humans, and in patients with a history of radiation exposure. This study looked at diabetic patients with refractory foot ulcers or radiation necrosis who were receiving hyperbaric oxygen treatments. The study was small and results varied more than in previous trials. However, the researchers reported that overall, hyperbaric oxygen therapy increased circulating CD34+ stem cells three-fold in the patients with diabetics, and was shown to play a role in wound healing. Three patients of twelve in the study group did not increase stem cells. The researchers said that the reason for no increase should be investigated.

In the exhibit hall of the hyperbaric conference, various companies display their fun oximetry units. There are several kinds of oximeters. The most common ones painlessly assess oxygen levels through the skin. Oximetry is used to assess oxygen available to the injured and surrounding tissue, and to tell how well hyperbaric oxygen treatments are working to improve oxygenation and new blood vessel growth. I like to try them all on, on different parts of my body. I experiment with different exercises to see the different effects on oxygenating different areas. Movement makes rapid, effective increases in oxygen levels.

In the past, people with diabetes were cautioned not to exercise because it was felt that they would injure themselves. Now it's known that exercise is an important part of preventing injuries from diabetes, and preventing or curbing diabetes itself. Regular exercise:

• Helps your body burn more sugar.
• Increases the number of insulin receptors on your cells and increases the sensitivity of your body to insulin.
• Helps your body grow new blood vessels and improve circulation.
• Improves oxygen levels to areas to help them heal.
  
• Reduces high blood fat levels (cholesterol and triglycerides) which leads to early aging of blood vessels.
  
• Increases blood flow to the feet, which helps prevent diabetic foot problems.

Keep moving for many aspects of preventing disease, secondary effects from disease, and to improve your health.


Here is the next post from the conference Exercise and Fitness in Decompression Sickness Risk.

Labels: circulation, diabetes, feet, fix pain, hyperbaric, scuba

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Exercise and Medicine Underwater and at High Pressure

For the next week, I will be at scientific meeting of the Undersea and Hyperbaric Medical Society (UHMS). My colleagues attending are flight surgeons, SEAL team captains, commercial divers, submersible and submarine craft personnel from navies of many countries, and scientists from all over the world who study the science of what happens to the body when working under different pressures, temperatures, and breathing gases - at altitude, underwater, and in the specialized dry compartments to build bridges and structures deep underwater. There are also physicians, technicians, nurses, and aerospace scientists and astronauts who use hyperbaric chamber technology to prevent or treat specific non-diving conditions. Allied health workers, divers, and non-divers also attend.

Originally, we were the Undersea Medical Society (UMS). As use of high-pressure oxygen chambers to treat illnesses other than diving climbed, more sessions on how hyperbaric oxygen works (and doesn't work) were added. Wound healing increased in focus. In 1986, we became the Undersea and Hyperbaric Medical Society (UHMS). Forums, sometimes strangely heated for brainy, cool-headed scientists, are held about which conditions legitimately respond to hyperbaric oxygen treatment and which are felt not to have evidence (no matter how much we wish it would work and alleviate the suffering of the patients).

Some of the established benefits of hyperbaric oxygen and some uses that are not shown to be effective are explained in the post and comments of Does Hyperbaric Oxygen Help Exercise Ability?

The meeting will cover many interesting topics in decompression bubbles that are thought to cause (or be part of) decompression sickness, or "the bends," and mathematical and empirical models of decompression. Decompression theory and bubbles were my research area for many years along with the effects of too much oxygen on the body during exercise underwater and in dry habitats underwater. The meeting will have many sessions in clinical hyperbaric oxygen therapy for several specific conditions (abbreviated HBO, HBOT, HB02 and other), chamber equipment, and wound treatment. There will be a session of The Veterinary Hyperbaric Medicine Society. Animals get problem wounds that need help healing, too.

The national board exam for hyperbaric chamber nurse and technician will be administered. There is also a board exam for physicians in hyperbaric medicine held each fall through the American Board of Preventive Medicine & Emergency Medicine. Information and background on both exams is on the UHMS web site. I wrote the study guides for both exams. I tried to make them fun, user-friendly, and packed with understanding, not just lists of facts and equations to memorize. The guides cover the entire contents of both areas and are a nice review or compendium for anyone interested I the field. Info is on my web site books page.

I won't be staying at the fancy conference hotel but at a backpacker's hostel. Over the next week, I will try to get to Internet cafes to post on some of the interesting topics and research at the meeting - and swim and go underwater for real. That is good for a researcher in underwater exercise and medicine to do.


Here is the next post from the conference Hyperbarics for Diabetic Foot Injury.

Labels: aerospace, education, hyperbaric, injury, scuba

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Does Hyperbaric Oxygen Help Exercise Ability?

Heavyweight boxing champion Shannon Briggs was in the Black Athlete Sport Network news for getting sessions in a hyperbaric oxygen chamber. According to the news, Briggs stated he believed the treatments would help him improve physically and get in better shape for his upcoming fight to undefeated heavyweight Sultan Ibragimov. What is hyperbaric oxygen treatment and what is the basis for use?

"Hyper" means more or above. "Baro-" comes from a Greek word meaning weight or pressure. Some words that use this word root are barometer, an instrument measuring atmospheric pressure, and bariatrician, which is a physician who manages obesity. In general, hyperbaric oxygen treatment consists of breathing 100% oxygen while inside a dry treatment chamber that is pumped to a pressure higher than you are breathing now.

Hyperbaric oxygen treatment is used to treat two kinds of scuba diving accidents - decompression sickness and air embolism, which can result from rapid pressure reduction if you come up too fast. Hyperbaric treatment has also been found effective for treating wounds that do not heal because they do not have enough oxygen, certain infections of problem wounds, diabetic ulcers, and other conditions to be covered in future posts.

Hyperbaric oxygen is a documented modality in treating problem wounds which have a poor blood supply (are hypoxic). Bringing additional oxygen to the deprived area makes the body better able to repair itself. There is no current evidence that hyperbaric oxygen speeds healing of normal injuries, sore muscles, or that it improves physical ability. In sports injuries there is no lack of oxygen. Often the opposite problem occurs. For example, an area that is hot and swollen may have plenty of oxygen and blood supply. Adding more oxygen would not make it heal faster. There are occasional debates about using treatment chambers for athletes. As evidence becomes available, I will add it here. There is heated debate whether hyperbaric treatment is applicable to conditions such as vascular headache, brain injury, neurologic conditions, and others.

For a sick patient with problem wounds, diving injuries, carbon monoxide poisoning, or gangrene, hyperbaric treatment can be life and limb saving. Regarding athletes who believe it will make them a better athlete, and feel they should use hyperbarics regardless of hard evidence, there are minor side effects to hyperbaric treatments. Without the ability to heal regular muscle soreness or improve athletic performance, the side effects would not be helpful, and could be potentially detrimental to the athlete.

One of many resources for information on hyperbaric treatment and chamber directories is the Undersea and Hyperbaric Medical Society UHMS. For books about hyperbaric chamber treatment, and becoming credentialed see my web site books page.

Labels: fix pain, hyperbaric, injury, martial arts, performance enhancing modality, scuba

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Wilderness Medical Elective

The Wilderness Medical Society will run the next wilderness medicine elective from February 5 to March 2, 2007, in the Smokey Mountains of Tennessee. Three of my students from last year, Neeta Abraham, Yvonne Chow, and Joey Brunkhorst, are pictured at left. I didn't do that to them. They were preparing for scenarios that simulate locating and rescuing injured adventurers.

I'll be at the elective again in February to teach three units of underwater physiology, scuba science, and diving medicine, some fun seminars in orthopedics, and a workshop on stretches that harm and how to change them to stretches that help. It's good for future doctors to know which of the traditional stretches and exercises are adding to injuries or are not effective, and what to do instead.

The wilderness elective is designed for 3rd and 4th year medical students, residents, and allied health profession students from accredited schools. The elective includes a 48 hour Wilderness First Responder Course and ends with a 4-day overnight field trek through the mountains, with the itinerary planned by the campers. In between are plenty of lectures, hands-on practice, and practice in outdoor rescue scenarios from first aid to advanced life support. It is directed by Dr. Tom Kessler, a wilderness medical society member, global doctor, volunteer physician for Native American reservations, exceptionally knowledgeable practitioner, and kind teacher with an on-target sense of humor.

The Wilderness Medical Society has extended the application deadline, which normally closes in August. Space is available for only 24 students. Check the WMS elective site for information, or e-mail Dr. Tom Kessler at tkphs@yahoo.com.

Labels: cold, education, hyperbaric

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