Hyperbaric Oxygen & Sports Medicine: It's Rationale and Use    Sporting events enrich our lives! The outcome of any game is always uncertain, which is why sports make for such great entertainment.  Unfortunately, while the score of the game is uncertain, injuries to the world's most elite athletes is inevitable.  Hyperbaric Oxygen Therapy (HBOT) plays an important role in the accelerated healing from sports injuries. Since the use of HBOT was first recommended for sports injuries over 20 years ago, HBOT has been applied widely in both training and rehabilitation from various sports injuries such as sprains, strains, tendon repair, fractures, swelling management, and most recently concussions research.

Training Rationale:  The primary transport mechanism for oxygen is hemoglobin with small amounts of oxygen being held directly in the plasma.  Naturally, a limiting factor in tissue oxygen uptake is the amount of available oxygen.  The amount of available oxygen can be elevated by increasing the amount of circulating hemoglobin through increased red blood cell numbers, increased cardiac output, or by increasing the amount of oxygen held directly in the plasma.  To achieve a significant increase in the amount of oxygen held directly in the plasma, the ambient pressure at which oxygen is consumed must be increased by full body emersion inside a hyperbaric chamber.  The use of varying atmospheric pressures as a training aid is certainly not new.  The experience of Mexico City demonstrated that altitude acclimated athletes performed significantly better than sea-level trained athletes.¹ 

Breathing 100% oxygen while exposed to hyperbaric pressures increases arterial oxygen partial pressures while limiting the deleterious effects of increased fractional inspired oxygen concentrations.  The increase in available oxygen enchances exercise tolerance by improving VO₂ max, reducing lactic acid production, and allowing the creation of a larger oxygen deficient while at the same time allowing that deficient to be met in the distal periphery.

Rehabilitative Rationale:  A serious detriment in high level competitive sports is the loss of an athlete to competition due to soft tissue injuries, inflammation and vasoconstriction, fracture healing and wound repair.  Recent investigations point to reperfusion injuries as a possible contributing mechanism in soft tissue injuries.

Reperfusion Phenomenon and Athletic Injury:  The event leading to reperfusion begins as the cell energy drops and is no longer able to maintain a proper ion gradient across its membrane.  This precipitates a redistribution of calcium and leads to increased amounts of adenosine and monophosphate (AMP).  The AMP is catabolized to adenosine, inosine, and hypoxanthine.  HBOT has been reported to reduce the reperfusion phenomenon by producing hydrogen peroxide (H₂O₂) and superoxides (0^-2) which are less caustic than hydroxyl radicals (OH^-).  The latest research shows further improvement by blocking CD18 adhesions ^2, 3 on cell membrane walls.  HBOT has been demonstrated to reduce neutrophil activation which has been theorized as another indices of reperfusion injury.  Finally, HBOT reduces the availability of transitional metals such as Fe⁺³.  Most of the research investigating HBOT's impact on reperfusion has been conducted in severe ischemic tissues ^{4, 5} but there is no reason to believe that even moderately ischemic tissues suffer from this phenomenon. ⁶  HBOT has been shown to reduce reperfusion injury. ^{7, 8}

Inflammation and Vasoconstriction:  Inflammation occurs in soft tissue injury through the release of fluids from the intracellular to the extracellular spaces.  This process might also be affected by reperfusion.⁹  HBOT has been shown to reduce compartment pressures ^{10, 11} by vasoconstriction with concomitant increase of tissue oxygenation.  The levels of arterial oxygen tensions provided by hyperbaric oxygen provide a strong vasoconstrictive effect which reduces blood flow yet increases oxygen tensions and the oxygen diffusion distance.  This mechanism reduces compartment pressures as well as reducing tissue edema.  The application of hyperbaric oxygen in the treatment and prevention of this injury will greatly reduce the time necessary for athletes to recover from injury or extreme muscle fatigue that often accompanies athletes in elite sports.  For the most powerful effect from hyperbaric oxygenation, the HBOT treatments should commence within 12 hours of initial injury.

Post-Concussion Injury:  Traumatic brain injury (TBI) and post-concussion syndrome (PCS) are all too frequently the result of motor vehicle accidents, or head injuries in sports such as the NFL, NHL, MLB, NBA, NCAA, etc.  Those who suffer from such injuries often endure long-lasting effects.  New research from Louisiana State University's Health Sciences Center offers new hope for those with TBI / PCS - even those whose injury may have been years before.  Research led by Dr. Paul Harch, Associate Clinical Professor of Medicine at LSUHSC and published in the Journal of Neurotrauma, found that treatment with hyperbaric oxygen nearly three years after injury significantly improved function and quality of life for those with TBI and post-traumatic stress disorder (PTSD).  "The magnitude of the improvements in memory, executive function, functional brain imaging, and quality of life, as well as reduction in concussion and PTSD symptoms cannot be explained with a placebo effect."  HBOT holds promise for those with Traumatic Brain Injuries. 

Fracture Healing and Wound Repair:  HBOT has significant benefit on fracture healing and tendon repair through its enhancement of osteogenesis and stimulation of osteoblasts and osteoclasts.  Increasing abnormally low tissue PO₂ values will stimulate fibroblastic activity.  Many non-healing tissues are hypoxic.  O₂ tensions frequently range from 5 to 15 mmHG.  Tissue oxygen tensions of 39 to 40 mmHg are necessary for fibroblastic synthesis if collagen and the subsequent development of a collagen mix.  Hyperbaric Oxygen re-establishes normal oxygen tensions through increased diffusion capacities from intact circulation and through angiogenesis.  Collagen and fibroblastic proliferation, which is crucial tissue matrix formation, are accentuated by HBOT. ^{12, 13, 14, 15}

The use of HBOT in the clinical setting has gained wide spread use in the past 20 years.  Investigators have made observations of increased density with smaller diameter of tendon when repaird tendon was treated with HBOT.¹⁶

Summary:  The use of HBOT in the rehabilitation and training of athletes is a new and exciting adjunct to traditional methods.  The rapid reoxygenation of tissues, both injured and stressed by exercise will benefit from increased partial pressures of oxygen that are delivered through hyperbaric oxygen exposures.  Large multi-person hyperbaric chamber systems manufactured by OxyHeal® allows for a wide range of training and monitoring equipment.  In addition, a large chamber allows several athletes to be treated simultaneously and for them to perform multiple tasks or receive various therapies while they are being treated in the chamber.  The well documented pathophysiology of oxygen's function in wound healing combined with over twenty years of clinical experience at large acute level hospitals provides sufficient jurisdiction for the use of HBOT to treat sports injuries.

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