Tuesday, November 12, 2013

Compression Garments, Part I: Before they were used for sport

By John Hobbs, MS. Senior Consultant

                Working in the complimentary fields of medicine and exercise physiology can provide insight in to new ideas and products.   It can also aid in teasing out how the theories behind various practices are developed.  An example of this is the use of compression garments to aid recovery and increase performance.  While increased recovery or enhance performance, regardless of the mechanism of action, is beneficial, a review of literature reveals little data supporting the benefit of compression garments in athletes.  Over the next several postings, the efficacy of compression stocking use in athletes will be evaluated.
                Compression garments are not new devices.  Their use in medicine has been wide spread for a number of years.  Forms vary from tight stockings covering from the calf and thigh to pneumatic devices that contract and release at programmed intervals.  The most common use is to prevent clots from forming in individuals with circulation issues.  Essentially, a pooling of blood can occur in the limbs called venostasis.  This pooling is a prime environment for small clots to form as the blood sits in place.  When an event occurs that allows the pooled blood to be pushed back to the heart, these clots can then cause strokes, pulmonary embolisms, and heart attacks.  This is the same mechanism that prompted walking and moving around in an airplane on long flights.  By compressing the limbs with appropriate garments, venous return can then be improved and therefore significantly reduce stroke and heart attack risk non-invasively.

                A key factor in this, however, is the role of an individual’s mobility.  The mechanism by which blood returns to the heart is called the skeletal muscle pump.  As a muscle contracts, the veins are compressed causing blood to be pushed under pressure.  It then moves towards the heart due to a series of valves in the vasculature.  These essentially make the veins one-way as they shut if blood tries to go the wrong way.  The valves are similar to airport security-- once you pass it, you can’t go backwards, but instead, have to circulate all the bay back around.
                Compression garments are not a standard issue item when a patient enters a hospital or other health care facility.  Rather, they are used in patients with severely impaired mobility.  This can include degenerative diseases, stroke, or simply being too weak to move.  Essentially, these individuals no longer have an effective skeletal muscle pump.  But, if or when mobility returns, the use of the garments is discontinued.  This can include a patient simply being able to walk to the bathroom or self-propel using their legs in a wheelchair.  I’ve even seen cases where physicians made a deal with patients that if they walked to the nursing station once every two hours they are awake, the order for the garments would be removed.  The key factor in this is the small amount of mobility required to negate the need for the garments. 

                Contrast this with the athlete population.  The skeletal muscle pump is used throughout exercise.  Then, after a workout, these individuals are able to move around normally, typically without any form of venous insufficiency.  With these facts, it appears that the method of action used in ill patients would not be applicable in healthy athletes.  However, since strenuous exercise may alter some bodily functions as well as the fact that a secondary mechanism of action may exist, it is still important to assess the data to see if benefits are seen as we will do in future postings.