Monthly Archives: December 2009

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Heat Acclimatisation by Paul Bateson


Heat Acclimatisation


Competing in any race is hard relative to the amount of effort you put in and your level of fitness. Whether it is a road half marathon or a multi stage ultra across remote and hostile terrain the one thing which can really affect your chances of finishing is the temperature.

Races over marathon distance such as ultras tend to be something that you progress to, but the one type of event which defies this logic is the multi-stage, multi day ultra across remote and exotic landscapes. The granddaddy of these is the Marathon des Sables and after 25yrs and despite the high entry fee it now attracts 800 entries, many are first time ultra runners and the highest entry numbers after the French, (the event is organized by the French) come from the UK.

The UK and northern Europe in general isn’t noted for having a particularly warm and dry climate, summers are short and temperatures of over 20C are rare. It is hardly surprising that to enter a race in which temperatures of 20C (68F) would be considered cool and 30C (86F) more likely with maximums of 38-45C (100-115F) quite possible, needs some proper preparation.

Unfortunately the failure to prepare for the heat is probably the biggest reason that people fail or struggle to complete this type of race. Months of training in cold, wet, dark, frost, wind and often snow mixed in with the odd nice day isn’t the best way to go into an early spring race (the MdS) across the Moroccan Sahara, July in Andalucia (Al Andalus) or October in Egypt (Sahara race). No amount of money spent on getting lighter and lighter equipment and clothing, comfortable shoes, hydration systems, dehydrated meals plus reading and ‘chatting’ on forums is going to prepare you for the biggest test of all, the heat.

So what can you do? Well you may be surprised to know that heat acclimatization takes only about 2 weeks, even so, going to a race two weeks before the start isn’t an option for the majority of runners with jobs, families and holiday limitations. An additional 2 weeks in the sun would also add to the financial burden and for something like, for instance, the MdS this will already have cost close to 5000 pounds when taking into account the entry fee, equipment, training and travel.

Heat Acclimatization is the process through which the body deals with being introduced to a hot environment. Exercise intensity and duration should be gradually increased over the first two or three days as this is the time period in which most serious cases of heat illness occur. A minimum daily heat exposure of about 2 hours (which can be broken into two 1 hour sessions) combined with physical exercise that requires cardiovascular endurance such as jogging or running can be increased in intensity or duration each day. Some research also suggests that as long as your training is fairly intense, maybe 85% of your max heart rate, running just 30 minutes a day for about a week will acclimate you to running in hot weather.

You can also simulate heat by overdressing, wear more layers than usual when training, maybe wear a none breathable (cheap) waterproof jacket (more for those going to races like Jungle and Indo ultra where high humidity is also a problem), run indoors on a treadmill wearing layers and with room heating on, work out in a sauna and have a hot bath each evening.

Warning: Before heat training get a medical check up. Many races require you to submit an ECG dated within a month of the race. A month before the race would also be a good time to begin the heat training. Make sure someone knows you are heat training, a gym is a safe environment as there should be staff around but out in the hills you should try to have someone with you. If this isn’t possible then train on a small circuit with water/electrolytes available each lap, maybe stashed at points around the circuit.

 The body’s sweat rate increases after 10 to 14 days of heat training. Because of this a greater fluid intake is required after acclimatization. In addition, increased sodium intake may be necessary during the first 3 to 5 days since the initial sweat rate will cause more sodium loss. After 5 to 10 days the sodium concentration in sweat will decrease and additional sodium supplementation shouldn’t be needed although I would still recommend you take Eletewater Tablytes after training and with meals before and during your race.

A high sweat rate can’t be maintained for hours so acclimatized athletes need to start each day pre-hydrated and not wait until they feel thirsty. However, an acclimatized athletes cells will become far better at picking up salt, and even though sweat flow may be four times the normal, the cells will absorb most of the salt. The kidneys also improve their ability to hold on to salt so that a fully acclimatized person in heat will need no more salt than an un-acclimatized person in temperate conditions.

 Heat acclimatization is a very important part of an athletes preparation, it isn’t difficult to do and costs relatively nothing but it will make a huge difference to your race performance. However, remember the benefits of acclimatization are only retained for about 2 weeks.

For many reading this your first encounter with hot weather racing will be the 2010 MdS, (assuming that the 2009 races cool/wet conditions were a one off) so I hope this article has been useful. For those looking at doing Al Andalus ( in July chances are it will be even hotter so make sure you are heat training prior to coming out.

For those who are planning for a future MdS, Al Andalus, Gobi Challenge, Libya Challenge, Augrabies, Sahara race or any one of the many great races around the world please also consider attending one of our Desert Runner Training Camps which we hold throughout the year. They will make a huge difference to your preparation and you will soon find out how well you perform in high temperatures. Just make sure you are ‘’heat acclimatized’’ before arriving in order to gain the full benefit of training everyday in the heat.

Paul Bateson

Andalucia, Spain.


In 2018, a race where you start anywhere you like, as long as you reach the finish within 24 hours. ...

Convergence - Summer

June 9, 2018, 12:00pm - June 10, 2018, 6:00am

It’s game time. In this game, you will gamble on your own fitness and ability. You know where the finish line is, but you are not following a fixed course; you “make” your own course. You tell no one else where you intend to start from. That way you are blind-betting against everyone as to from how far away you will start, and thus, how high you will eventually rank. Those who travel the furthest, rank highest. However, if you don’t reach the finish line you don’t get a medal, so gamble wisely…. The premise is simple. You can start from anywhere you want, at midday. You then have 24 hours to ‘converge’ on the central finish line in order to claim your award. You make your own route. You can start any distance from the finish line, but the further away you start, the better your award (should you make it to the finish). All distances are measured “as the crow flies” from the finish. For all those challenging this is where it gets even more interesting. The people who rank highest are those who travel from the furthest away. You are under no obligation to tell anyone where you are starting, so you are all blind-betting against each other! You won’t know where anyone starts from until the GPS tracking link goes live at midday. Even then, will those who started far away make the finish line on time? Of course if you start 100 miles away and miss the finish line cut-off, then you don’t get a medal. Oh, the cruelty. The Crow will be watching all of those Converging, using the miracle of Race Drone event tracking technology. The Crow will judge how far the shadows have run, and reward them with the right medal on the line. If you travel from 30 miles away or fewer, we’ll email you a certificate only. Venture from further away (30 to 60 miles) and claim a Silver Convergence, 60 to 90 miles and you’ll take Gold. If you come from 90 miles or more away (As the crow flies), then you’ll claim the Black Convergence medal. There is a little more to tell you. You can Converge only on foot. The Crow knows how fast you travel You can Converge solo for 24 hours, either female or male If you are scared of the dark, you can converge for 24 hours as a pair You will be given no advice on where to run, or hide You make your own route. Use any means you wish to wayfind You obviously can’t use private land or anything illegal (motorways etc). Your route choice is your own choice and risk. We recommend strongly that you stay off A-roads, or roads that have no pavement There are no checkpoints. Use your wit and guile to feed yourself. Call for your mother if you must The World will keep an eye on you from afar using tracking technology Have more questions? The wise old bird has the answers Feel ready to take your first steps into a darker world? Register Here

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