UP SEMLI study reduces life-threatening medical emergencies during endurance events by 64%

Posted on January 16, 2019

A first-of-its-kind study conducted by Professor Martin Schwellnus of the University of Pretoria’s Sport, Exercise Medicine and Lifestyle Institute (SEMLI), in partnership with UCT, the MRC Biostatistics Unit and Professor Wayne Derman of Stellenbosch University, has led to a 64% reduction in life-threatening medical emergencies encountered during marathons and other major endurance events. The study – which used an online medical screening and education intervention tool ahead of race day – found that other medical encounters, including all types of injuries, were reduced by 29%.

The results could have significant implications for and reduce deaths at some of South Africa’s favourite mass sports events such as marathon races, half-marathons, and cycle tours. Thousands of participants in these popular events end up in the medical tents annually, reporting serious life-threatening medical emergencies and overwhelming the healthcare system on the day. The results of Prof. Schwellnus’s study have been so impressive that the international community of athletics, triathlon and cycling have shown interest in incorporating this system into their registration processes for their mass community-based sporting events.

“Medical emergencies at mass sporting events are not just innocuous occurrences, but significant and severe encounters that are happening more often than they should be,” says Prof. Schwellnus, Director of UP’s SEMLI, who has been working in these medical tents for the past 25 years. Prof. Schwellnus, previously at the University of Cape Town, led this study, with the overall objective of making mass community-based endurance events safer for all participants.

The study introduced an online pre-race medical screening and educational intervention programme over an eight-year period in one of Cape Town’s world-favourite sporting events, the Two Oceans Marathon. Over the eight years, the researchers studied the 153 208 Two Oceans race starters in both the 21km and the 56 km events. The first four years comprised a control period, looking at the type of medical encounters that occurred, and the number of runners participating.

After this control period, Prof. Schwellnus and his team introduced an online pre-race medical screening which was based on the European Association for Cardiovascular Prevention and Rehabilitation (EACPR) pre-exercise screening guidelines and included other risk factors identified by the research team. Each person who completed the pre-race screening was categorised into one of four categories, with “Very High Risk” and “High Risk” being the flag categories. People in these categories would receive educational intervention programmes.

The educational intervention programme was specifically targeted at the two flagged categories, and there was also a general educational intervention for all runners. “The targeted educational intervention emails included information about what the runner’s doctor should test that individual for, because often doctors are not even aware of the specific risk factors experienced during prolonged moderate- to high-intensity exercise,” Prof. Schwellnus explains.

The risk of a medical encounter, including sudden death, during such prolonged moderate- to high-intensity exercise is related to extrinsic factors, including environmental stress and race distance, and also intrinsic factors such as older age. Underlying chronic disease such as heart disease and diabetes and risk factors for chronic disease also put an individual at greater risk for medical complications during such events.

“It is of utmost importance to ensure medical support is of the highest standard on race day, so that if someone goes into sudden cardiac arrest a medic is there to assist, and there is a good chance of resuscitation,” Prof. Schwellnus says. “But we want to prevent runners from even getting to that point. This online medical screening focuses on prevention rather cure.”

Educating people about their health and their possible risk factors is vital, because cardiac arrest and other life-threatening encounters won’t necessarily only happen on race day, but could also happen during a training run. Runners therefore needs to be as informed about their health as possible, particularly when they fit into the high-risk profile.

This pre-race medical screening system and educational intervention programme is easy to implement and – with a significant 64% reduction in all medical encounters since its introduction – it’s not only saving lives but also contributing to improved race safety.

This study at SEMLI forms part of a series of SAFER (Strategies to Reduce Adverse Medical Events for the Exerciser) studies which aim to better understand what is happening at these mass community events, who is participating, and what their risk profiles are – all in an effort to ensure safer participation so that the numerous health benefits of physical activity continue to outweigh any health risks.

- Author Louise de Bruin

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