Electric shocks and E.Coli: Oh Mudder, where art thou?

For some people, the outdoors means that draughty space between house and car; for others, it is a chance to escape the stresses of life. Walking is the simplest escape route, but it is often regarded as a waste of that all-important category, time. As the writer Rebecca Solnit observed, “I suspect that the mind, like the feet, works at about three miles an hour. If this is so, then modern life is moving faster than the speed of thought, or thoughtfulness.”

Perhaps this fast-moving nature of our daily lives helps explain not only why more people prefer to run or cycle than to walk, but the popularity of extreme sporting activities such as Iron Man triathlons and mountain ultra-marathons: events that allow participants to pack intense activity into a relatively short time.

The well-documented health benefits of exercise are beyond doubt, but having an awareness of some potentially hazardous aspects of outdoor exercise might both enrich our experience of such activity and prevent us getting ill, or worse.

Over years of running along damp country lanes, I've inhaled many a manure-enriched aerosol thrown up by the wheels of passing vehicles. And a recent case reported in the Journal of Infection Prevention makes me realise how lucky I've been. A 23-year-old male had competed in a cycling event along wet, muddy tracks in rural Scotland, and removed his mudguards to reduce weight. During the race, wet, muddy water from his own, and other, bikes splashed his face. Eight days later, he was hospitalised with vomiting, stomach pain and bloody diarrhoea, caused by infection with the bacterium E.coli 0157, which lurks in animal faeces and farm slurry.

Gastrointestinal illness

A two-year study of Norway’s Birkebeinerrittet, one of the world’s biggest mountain-bike races, found that when competitors used mudguards and spat out the first sip of fluid from a bottle, the rate of post-race gastrointestinal illness fell from 16.3 per cent in 2009 to 4.9 per cent in 2010.

The researchers recommended using mudguards: “While front mudguards can help reduce risk for the individual participant, rear mudguards are more important in reducing the risk in cyclists following.”

But while mud is an incidental hazard in cycling, thick mud is central to the Tough Mudder experience. The Tough Mudder is a 10 to 12-mile endurance race around an obstacle course. Obstacles include the Kiss of Mud, where competitors crawl through mud but beneath barbed wire suspended eight inches above the ground; Bale Bonds, comprising a bale of loose hay, over or through which participants propel themselves; and the ever-popular Electroshock Therapy, which requires entrants to run through mud and water while avoiding electrical wires that deliver 10,000-volt shocks to those who collide with them.

I found these facts in the March 2014 issue of Annals of Emergency Medicine, which describes how a participant drowned in April 2013 in the US state of Virginia, while meeting the challenge of Walk the Plank. This entails jumping from 15ft into a pool of freezing water. And in June 2013, a local hospital's emergency department in Pennsylvania was visited by 38 of the 19,000 Tough Mudder competitors; two of them had suffered heart attacks.

Since its inception in 2010, the Tough Mudder has attracted 1.5 million participants worldwide, and in July, Ireland’s second Tough Mudder will be held in Co Meath; ominously close, one might speculate, to the prehistoric cemetery at Loughcrew.

Triathletes

But for those who consider electric shocks and the risk of infection incompatible with the typical health benefits conferred by outdoor exercise, a triathlon is hardly freighted with these dangers.

Yet, according to Dr Randy Eichner of the American College of Sports Medicine, between 2007 and 2013 at least 52 triathletes died while competing, 44 during or after swimming. More than half of them were middle-aged males.

Eichner speculates that the chaotic nature of mass starts in deep choppy water, combined with trauma, panic and tight wetsuits may cause weak swimmers to hyperventilate, inhale water and drown, or suffer a cardiac arrest.

As for marathon runners, one little-recognised hazard beyond blistered feet is exercise-associated hyponatraemia (EAH), caused by voluntary over-drinking.

Throughout the 1960s and 1970s, marathon runners seldom drank – or did so sparingly – and often recorded superior times to those being clocked today. However, from the running boom of the 1980s a myth evolved and it fuels the fear of dehydration prevalent among many runners.

The myth is that anything more than a 2 per cent loss of body weight during an endurance event will have an adverse effect on performance. Yet it is an evidence-based fact that runners who do best in marathons are often the most dehydrated. The rule is, drink to thirst. No endurance athlete has died of dehydration, but there are at least 12 documented cases of sportspeople who died from EAH through voluntary over-drinking.

Another myth that even some physicians are prone to believing is that dehydration is a risk factor for heatstroke. Prof Timothy Noakes of the University of Cape Town, whose team first established the cause of EAH, states in his book Waterlogged (2012): "There is no published evidence to support the hypothesis that heatstroke is caused by dehydration and that it can be prevented by drinking as much as tolerable during exercise."

The health- and life-enhancing enjoyment of outdoor exercise cannot be overestimated, but it’s possible that some of its associated risks may be underestimated.

Time for my walk . . .