By Dr Amy Boalch, Doctor & Running Coach

The recent London Marathon saw over 50,000 runners complete the iconic 26.2 mile course¹, passing the Cutty Sark, Tower Bridge and Buckingham Palace to name a few. But, dispersed along the route, were also 1500 St John Ambulance staff as well as doctors, physiotherapists, podiatrists and paramedics².  Thankfully, most runners never even know these healthcare professionals are there, but have you ever wondered what happens behind the scenes in the numerous medical tents and ambulances? Here’s a brief look at just some of the medical problems that might occur during a marathon event.

Blisters

We can’t talk about running first aid without mentioning this common culprit. Blisters occur due to frictional forces that create shearing between layers of the skin, a situation worsened by heat and moisture. The way blisters are managed will depend on their size. Small blisters will often resolve on their own and many marathoners may not notice they’ve developed until after they finish the race. These can be self-managed by off-loading the skin with a donut type dressing or cushioned plaster and keeping an eye out for signs of infection. Larger blisters may require a bit more intervention to help relieve pain. This might include a first aider using a small blade or needle to decompress the area whilst leave the roof of the blister intact to aid healing.  Of course, the best medicine is prevention rather than cure, so make sure to race in well-fitting running shoes and moisture-wicking, breathable running socks that you’ve practiced using before.

Exercise-Associated Postural Hypotension

This condition causes athletes to collapse after they’ve crossed the finish line. It’s the most common cause of collapse in marathon runners and is related to the sudden cessation of movement. This process of suddenly stopping results in less blood being pumped back up to the heart, making the runner feel light-headed and dizzy. They can then collapse – this is a vasovagal event or ‘simple faint’. The treatment involves lying the athlete down and elevating their legs. As before, prevention is better than cure, so continuing to walk after crossing the finish line can be very helpful!

Exertional Heat Illness

As the name suggests, exertional heat illness is when core body temperature rises due to exercise. This occurs because of increased muscle activity and metabolism. This is balanced with heat loss, which is achieved largely through sweating. In hot and humid conditions, however, this becomes less effective as there is reduced sweat evaporation. As a result, the body can overheat. Very simply, if athletes have a high core temperature (>40C) but are otherwise well this is known as hyperthermia. If athletes have a high core temperature (>41C) and are unwell, this is heatstroke – a medical emergency. Management involves rapid whole-body cooling which essentially means cooling down the body as quickly as possible through whatever means available – ice, fans, cold water. In terms of prevention, good acclimatisation to hot and humid environments is essential and runners should avoid exercising when unwell as viral infections increase the risk of heat illness.

Exercise-Associated Hyponatraemia

This condition refers to low blood sodium levels in athletes either during, or up to 24 hours, after exercise. Blood sodium levels become low due to a dilutional effect which means that anything that increases fluid input or reduces fluid output can increase the risk. This includes drinking water in excess, taking NSAID medication such as ibuprofen, and having kidney problems. The condition is common and often asymptomatic, with around 12% of marathon runners experiencing asymptomatic hyponatraemia³. These cases will often never reach medical attention, but management would involve taking on salty foods and holding off on fluids until the athlete is passing urine. In severe cases hyponatraemia can lead to confusion, collapse and even death. These cases require immediate, specialist management and transfer to secondary care.

Exercise Induced Abdominal Pain

The gut can be a cause of many complaints for runners, a common one being an abdominal ‘stitch’ or ‘cramp’.  The cause of these symptoms is unclear, and likely multifactorial, but it tends to more commonly affect new runners and runners who significantly increase their load. To try and reduce the chance of this discomfort striking during a marathon, nutrition can be optimised by ensuring appropriate gaps between eating and exercising; opting for sports drinks that contain a mix of fructose and glucose rather than a single carbohydrate; and avoiding NSAIDS like ibuprofen as these increase the risk of gastrointestinal symptoms.

All of this can sound a little scary, but the benefits of exercise far outweigh the risks and since 1981 over one million runners have safely crossed the London Marathon finish line⁴.  Here are some top tips for staying healthy if you’re running a marathon:

1. Think before you drink
2. Avoid ibuprofen 48hours either side of race day
3. Don’t run if you’re feeling unwell

Read more here: https://www.tcslondonmarathon.com/news-and-media/latest-news/medical-advice

References

1. TCS London Marathon (2022). 2022 TCS London Marathon Stats. Available at: https://www.tcslondonmarathon.com/news-and-media/media-resources/2022-tcs-london-marathon-stats (Accessed 13/10/22)
2. Sanjay, S (2022) [Twitter] October 2^nd. Available at: twitter.com/SSharmcardio/status/1576478269540401154 (Accessed 13/10/22)
3. Kipps C, Sharma S, Pedoe DT. The incidence of exercise-associated hyponatraemia in the London marathon. British Journal of Sports Medicine. 2011 Jan 1;45(1):14-9.
4. TCS London Marathon (2022). Taking care of your health. Avaiable at: https://www.tcslondonmarathon.com/news-and-media/latest-news/medical-advice (Accessed 13/10/22)

Article written by: Dr Amy Boalch

Dr Amy Boalch is a junior doctor and running coach who is passionate about improving physical activity levels for the benefit of both physical and mental health. She is currently training as a GP in Bath and completing a Masters in Sports Medicine, Exercise & Health at University College London.