The hidden dangers of marathon running

The very first marathon runner, Pheidippides, may have died of exhaustion but over 860,000 people still applied to run last year’s London Marathon.

When Pheidippides reportedly ran from Marathon to Athens to announce victory over the Persians in 490BC, he wouldn’t have known he’d started a major trend. But maybe we should be paying more attention to his sad demise, as this is an endurance event despite the increasing numbers of people wanting to take on the challenge.

I experienced it myself in 2018, running the hottest London Marathon to date at 24C. The race day was exhilarating, even though I’d only trained up to 21 miles and relied on adrenaline for the final five miles. I finished in a decent time and raised money for a good cause but the aftermath told a different story: prolonged soreness and fatigue took a toll on my 47-year-old body that took an age to recover from. When I returned to running, I opted for shorter, more manageable distances like 5k park runs on softer terrain. But, for many others, completing a marathon is just the beginning, sparking a pursuit of even greater endurance challenges. Though, be warned, that runner’s high, a sense of accomplishment and wall full of medals can come at a crippling cost.

The most common injury pitfalls

According to a recent survey of 7,600 runners, 84% of first-time marathon runners sustain a running-related injury during training. Separate research – tracking over 1,000 marathon runners – found that overuse injuries nearly triple in prevalence as training progresses, peaking in the final training quarter. Dominic Rae, Head of Sports Medicine and Performance Specialist at Ten Percent Club, says the final weeks are where the most avoidable damage is done.

"Runners have put in months of work and they're so close that they ignore the signals,” says Dominic. “A niggle becomes an injury. A missed nutrition window becomes a 'wall' at mile 18. The runners who get hurt at this stage are often the ones who've trained the hardest.”

Another common mistake new runners make is underestimating the cumulative load of marathon training rather than the event itself. “Many first-time runners focus heavily on completing long runs but neglect their training plan and adequate recovery,” warns Dominic. A typical issue is ramping mileage too quickly, which significantly increases injury risk, typically a tendon injury from overuse.

With all sports there are risks of course but road running is associated with quite heavy load on the joints (especially running on pavements). “From a musculoskeletal perspective, repetitive high-impact loading without sufficient strength or adequate recovery can lead to chronic tendon issues, joint changes or even stress fractures,” adds Dominic. These are often a result of asking the body to do more than it can tolerate and adapt to.

The health issues you wouldn’t expect

Joint pain, tendon strains and muscle tears are the type of injury that you might expect from long-distance running on hard surfaces. But there are more, hidden and unexpected, risks too.

“Hormonal and metabolic consequences need to be considered, particularly in individuals who chronically underfuel and under-recover,” Dominic adds. “Relative Energy Deficiency in Sport (RED-S) is increasingly recognised in endurance athletes and can impact bone health and immune function, which will affect overall performance.”

While heart-pumping, circulation-boosting exercise like running generally improves cardiovascular health, endurance distances like marathons and ultramarathons (typically 50k/31 miles and more) can carry a low, transient risk of sudden cardiac death, some studies show. However, this is most likely when there’s a pre-existing condition or undiagnosed coronary artery disease. “Cardiac screening, such as an ECG or echocardiogram, may also be necessary for those training at high levels,” suggests Dominic. “Especially for those with a family history of cardiac issues.” Experts warn that runners should look out for any gradual decline in performance or increasing effort for the same pace – signs of underlying fatigue. “Changes in resting heart rate, heart rate variability or sleep may also signal chronic fatigue or systemic stress,” adds Dominic. “It's important to keep an eye on these things.”

Running on empty or improper fuelling can contribute to longer-term health issues too, according to Professor James Fleming, Associate Head of Nutrition at St Mary’s University London. “Without adequate periodisation and planning the body can struggle to adapt, and you may be more susceptible to injuries. This also ties in with supporting the body by fuelling training and recovery. Thinking about what we eat after training as well as before, as the body only gets better after it is fed with good nutrition and adequate rest (including sleep quality and quantity) and recovery.”

How to outrun the risks

It’s perfectly possible to reap the rewards of running marathons and stave off some of the potential long-term side-effects of endurance exercise with the right amount of pre-planning and post-run recovery moves. “One area where first-time marathon runners go wrong is not allowing themselves enough time to train,” insists Lewis Moses, head coach at RunThrough (runthrough.co.uk). “Starting training earlier than January if you’re running an April marathon, getting ahead of the game and building that base from further out is much better and reduces that risk of injury as you gradually build up the miles in the legs and the body adapts comfortably.”

So as long as you're doing things in moderation and with proper form and recovery, running can improve bone health some research shows. Lewis says a lot of runners make the mistake of neglecting strength training for fear of bulking up. It’s something Dominic concurs with. “Targeted loading of key areas, such as the calf muscles, quadriceps and posterior chain, using exercises such as squats, lunges, bridge and hip hinges will build lower body strength in both muscles and bones.”

Simple nutrition choices can also help protect and strengthen your bones if you’re continuing to run long distances. “Nutrients like calcium and vitamin D are key to bone health,” insists Karine Patel, sports dietitian at Dietitian Fit. But they don’t work on their own. “Vitamin K, magnesium and protein all influence keeping strong, resilient bones. I always encourage people to focus on balanced whole foods. Leafy greens like broccoli and kale, dairy products, seeds, nuts and oily fish are all great choices. For those following a plant-based diet, fortified foods also help fill any nutritional gaps.”

Stay strong, eat well and monitor your heart, and you’ll make great strides to reaping the rewards of running without finishing the way Pheidippides did.

Enjoyed this? Read more:

More marathon training & nutrition guides
What should I eat when training for a marathon?
Carb-loading explained
Marathon countdown
What to eat after a run

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