Heat Acclimatisation for spring races

With the first hint of spring in the air it is time to give some thought to what impact warm weather could have on your spring race plans, especially if you are planning a late April or May marathon.

In recent years the London Marathon has been affected by unseasonably warm weather on a couple of occassions. Warm weather has several affects, most of which are performance reducing for endurance athletes. The bottom line is that warmer weather makes our body work harder to keep cool. That means pumping more blood to the skin rather than the muscles and losing more fluids and electrolytes as sweat which in turn reduces blood plasma volume and the hydration levels of the cells. So sticky blood and badly lubricated muscles. Imagine a car engine with sludge in the fuel tank and no oil left in the gearbox and you start to get the picture.

The good news is that there is plenty you can do to be prepared. The starting point is to know what weather to expect in your target race. A look at one of the weather websites such as Wunderground can show you historical data and seasonal norms. Something to be wary of though is 'average' temperatures. Far more important is the range of temperatures you can expect. For example in March 2008 London had a range of -2 to 14 degrees whereas Amman in Jordan had only a slightly higher average but a range of 0 to 32 degrees. Clearly if you got caught out with a 'hot' day in Amman it would have a much bigger impact on your performance than a 'hot' day in London !

So how can you acclimatise for warm weather during a european spring ? Well the extreme version would be that practised by a former british olympian who put a cycle machine in his bathroom, turned the heating up full blast, filled the bath with hot water for added humidity and then in full tracksuit proceeded to pedal to exhaustion. Its not something I would advocate though ! For some athletes a spring warm weather training camp is part of the answer. The Algarve, South Africa, Tenerife and Cyprus are all popular locations at this time of year. But if this isn't an option there are a few practical solutions at home.

Make the most of the warm days when they occur. Last weekend was warm and sunny and I went running in the early afternoon when the temperature was at its highest. If that doesn't fit with your schedule then doing some runs indoors on a treadmill can work, especially when the local gym is at its busiest (and warmest). Adding some extra clothing also does the job. Although contrary to popular opinion you don't need to be wrapped up like a Michelin man. A hat and gloves are enough to fool the body's thermostat and give you some heat acclimatisation.

And if you are concerned that you have left it too late the good news is that the body adapts to heat stress relatively quickly. Athletes going to race in hot conditions often report that 10 day acclimatisation period is enough. So some carefully planned easy training sessions in te gym/sun/with hat and gloves can give you just the boost you need and leave you well prepared in case of a warmer than average day at your big race. And a final thought is that recent research from the Australian Institute of Sport showed that heat training stimulated an increase in blood plasma volume which could result in improved performance in normal conditions.

Updated July 2011
Running Times article on heat