Mercury Rising

2008-01-12 00:00

OLYMPIC marathon champion Stefano Baldini recently commented that: “When the weather is hot and humid personal bests go out the window.” His comments come at a time when a growing number of people are becoming concerned about adverse weather conditions, and their effect not only on elite performances, but also the apparent increase in medical conditions amongst average runners.

There have been suggestions that this is yet another impact of global warming, while others feel it relates to the standard of preparation among participants in major events. Irrespective of the cause, for years the New York marathon has adjusted the elite athlete time bonus incentives downwards whenever the race conditions exceed 20°C and humidity climbs through 60%.

“No-one likes to run in hot humid conditions, but I manage to race well in them,” continued the 36-year-old Italian who was well off the pace early in the Athens Olympic marathon, before moving through the field from 30 km to secure gold in the final few kilometres.

It is his tactics and appreciation of the effect of weather conditions that has delivered bronze medals in the 2001 and 2003 World Championships marathon and added the 2006 European Championship marathon gold to his Olympic title.

In spite of relative lacklustre performances in recent big city events and a personal best of 2:07:22 placing well outside the top 50 best ever times, Baldini’s pace and condition judgment place him among the favourites for the podium in the sweltering cauldron of the Olympics in Beijing.

The adverse effect of heat and humidity had a major influence in Europe last year, with the most prominent incident in London where temperatures reached 23°C with radial temperatures soaring to 27°C. A 22-year-old runner died at the end of the race that he completed in just over three hours and 30 minutes, ironically not from dehydration, but over-hydration, as authorities and advisers struggle to get the message through to runners about how to cope in these conditions.

One person died and 49 were hospitalised in the La Salle Chicago Marathon, which the organisers cancelled when the mercury climbed to 30°C.

Around 10 000 of the 45 000 registered runners chose not to start, despite additional mist stations, cooling facilities and water-soaked sponges, while another 10 934 started, but did not finish. Understandably in the United States, where litigation is king, officials closed the course three hours after the start: heat stroke is possible at any combination of ambient temperature above 26,7°C and relative humidity above 40%.

A lack of fitness and high body fat increases the risk of heat illness. Studies on American marines show that those unable to run 2,4 km in under 12 minutes and with a body mass index (BMI) over 22 were eight times more likely to suffer heat illness in basic training. It’s an easy assessment for any runner to do for themselves. (BMI = weight [kg] divided by height divided by height).

As we commence KZN’s first racing weekend of 2008 it is worth runners of all standards acknowledging the effects of weather as they enter the local events. Researching the coastal weather over the past three years indicates the average starting temperature in January to March at 5 am has been over 22°C, with humidity of 85% to 88%.

By the finish of a half-marathon the temperature has climbed a couple of degrees while humidity has dropped only four percent and as the last qualifier in a marathon crosses the line they are running in 26 to 27°C and humidity that is only just beginning to edge under 70%. Normally by 7 am, the effective temperatures are boosted by the radiant effect of the sun on the road.

These conditions are not dissimilar to those of the 2007 Osaka World Championships, which saw Catherine Ndereba, a 2:18 marathoner, have to settle for a 2:30 gold medal performance. This equates to a 3:48 marathon for a runner normally capable of 3:30, and 4:50 for a typical 4:30 marathoner. Importantly even these times will only be achieved if the runner adopts a sensible race strategy from the outset.

Experienced coaches and medics advise runners to start slow in stifling conditions as opposed to racing off at full tilt. Adopting the club slogan of an American friend makes sound advice for the early months: “Start slow then taper. Don’t drive halfway to heaven in the first half.”

According to a research review by the Gatorade Sports Science Institute: “With the exception of massive bleeding, exercising all-out in extreme heat is the greatest strain on the cardiovascular system.”

While the ravages of incorrect hydration and heat may cripple marathon times, the shorter distance events are more intense and are more likely to find inadequacies in cardio systems. Last year more German road runners, both young and old, died in short distance events than in marathons. The German Road Races (GRR) organisation feels that runners must accept greater self-responsibility before racing.

They recommend runners undergo a cardiologist examination and complete a catalogue of questions based on the views of leading doctors and sports medical institutes in Germany before racing. (see side box).

Recognising the signs of heat stroke is important to runners. Ironically, symptoms include chills and gooseflesh, which signal the shutting down of circulation to the skin, and results in a faster rise in temperature, with a possible increase in breathing in an attempt to shed heat in the same way that a dog pants.

This can also be accompanied with tingling fingers prior to collapse.

The swollen finger feeling is typically associated with dehydration, but it is important to remember that generally dehydration will see the runner grind to a halt, whereas over-hydration is responsible for more running deaths as the plasma becomes excessively diluted prompting the runner to go into a coma.

By weighing yourself before and after training in various conditions you can determine how much you sweat per hour. General recommendations are to replace slightly less than this amount per racing hour using a drink containing some electrolytes.

Although in “normal” South African conditions this may typically be 600 ml per hour, in the first three months of the year many sportspeople in KZN’s coastal conditions find this increasing to double that figure: test it for yourself.

Making sure you are fit, drinking correctly, setting a realistic target time for the conditions, and correct pacing will not only make racing enjoyable, but could also save your life in these hot and humid times, so whatever you do — be careful out there.

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