Hypoxic Training: A Risk Analysis
January 15, 2014
Shawn P. DeRosa, J.D.
Manager of Aquatic Facilities & Safety Officer for Intercollegiate Athletics
The Pennsylvania State University
Shallow water blackout (“SWB”), also referred to as hypoxic blackout, is a term describing loss of consciousness arising from oxygen deprivation brought about by voluntary or involuntary hyperventilation.
In swimming, voluntary hyperventilation occurs when a swimmer intentionally “overbreathes,” blowing off carbon dioxide. Involuntary hyperventilation can occur as a result of stress and physical exertion during a workout that pushes the swimmer beyond his/her maximum aerobic capacity (VO2 max).
This “silent killer” of otherwise healthy, accomplished swimmers should give pause to every coach and aquatic director around the world. Do we need to rethink how we run our practices or manage our facilities?
The dangers of breath holding are well known and well documented. The U.S. Naval Center website contains multiple examples of competent swimmers who lost their lives to shallow water blackout. Media outlets continue to highlight drownings of swimmers found unconscious, underwater following breath holding activities. In February 2013, swimmer Alex Bousky of the Peoria Notre Dame Varsity swim team suffered a non-fatal drowning. Bousky’s team is reported to have been working on how far they could swim underwater.
Industry groups including USA Swimming, the American Red Cross, the National Swimming Pool Foundation and the U.S. Navy have long cautioned against underwater breath holding activities, particularly those involving hyperventilation. Other groups, such as the YMCA of the USA and the Department of Morale, Welfare and Recreation of the U.S. Navy outright ban such extremely dangerous activities. Why? Because SWB has been proven to kill otherwise healthy swimmers.
While USA Swimming has not mandated a ban on restricted breathing training on the surface of the water, the national governing body for swimming admits that there is “no evidence that swimming without oxygen necessarily trains the anaerobic system.” USA Swimming states that there is a difference “between having swimmers hold their breath while swimming under water versus an extended breathing pattern while swimming on the surface.” The latter, is thought to improve oxygen management capacity. The former has proven to be deadly.
While USA Swimming and the American Red Cross continue to educate coaches regarding the difference between extending the breathing pattern on the surface and breath holding drills beneath the surface, some coaches continue to place athletes at risk of injury or death by doing “over/unders” or “lungbuster repeats.”
Even more dangerous is when a coach puts pressure on the athlete to swim extended distances underwater, such as by requiring an entire team to repeat an underwater drill if any one athlete surfaces to breathe. This creates a concern for athlete welfare as well as a potential area of liability, both for the coach and the employer.
Aquatic programs are advised to follow a risk management approach to addressing safety and liability concerns presented by hypoxic blackout. This entails evaluating the nature of the risk before selecting a risk aversion or risk management strategy. This also requires distinguishing between underwater drills and those conducted on the surface of the water. As both drills can lead to SWB, an evaluation must be made as to the likelihood or frequency of SWB resulting from such drills as well as the possible severity of such occurrence. Read more