Marathon Management

 

by Rebecca Lee - 24.04.09

Putting the body through a gruelling 26 miles can have a number of impacts on the body, which need to be prepared for and managed.

With the London Marathon seeing thousands take up the challenge this Sunday, EIS Physiologist Charlie Pedlar talks eis2win.co.uk through some of the key factors runners will face.

Keeping your cool: from the onset of running body temperature rises and it’s crucial in a marathon that a thermal balance is reached , ie heat production must be less than or equal to heat loss. This will be impacted by environmental conditions, fitness of the athlete and the clothing selected. At the start of the race there is a 18-20 minute window at the start of the race when the body is cool so has a greater heat storage capacity.

Fuelling: at any point in the marathon there’s a combination of fuels being used by the body – carbohydrate is the main one (around 700g burned over a marathon), although some fat (around 300g) is burned and some people are greater ‘fat burners’ than others, depending on the training status of the individual. Protein catabolism occurs in long distance races, amounting to between 5 and 10% of the total energy production, some from the diet, some from body stores. Elite athletes will not take on much fuel during the race due to experience and the training they undergo, however for the majority of runners they will definitely need to fuel as they go.

Thirsty Work: during the marathon the body loses fluid through both sweating and breathing. The amount depends on the individual but runners should consume more fluids than they have lost during the race.  And it’s not just water lost through perspiration. Sweat also contains salt which helps the body to absorb and retain water. Again, elite athletes will have less fluid they need to replace as will be experienced in endurance training but for most runners, stopping at every drink station to replace lost fluids is advisable.

Hitting the Wall: when the body is running on empty the term ‘hitting the wall’ is used and is a problem that affects marathon runners. Around the 18 mile mark, the body’s glycogen stores are depleted and it’s necessary to draw on ‘survival’ energy, eating away at your body’s protein and fat. The best way to restore glycogen levels is to take on water and energy drinks. This however, only has a partial effect as the body doesn’t absorb fluids as effectively fluids during exercise. Appetite is therefore suppressed during exercise and often afterwards for a period, however taking on water and sports drinks/gels can help the body recover quicker.

Muscle Management: The constant pounding of exercise causes tiny micro-damage and undetectable  tears in muscle tissue and bone damage. Cramps are likely to occur, causing an involuntary spasm of the muscles. Whilst it is not fully understood what causes cramp, fatigue and dehydration can affect them so taking on fluids and gentle stretching can help runners overcome them. The body will try to support its tissues and prevent further damage which can lead to a small amount of swelling.

Think Joints:  every step has the equivalent force of 2-3 bodyweights and it’s estimated that an athlete will finish the race two centimetres shorter than they were when they began due to joints being compressed. This is however a reversible effect and lying down and sleeping will allow the body to return back to normal. In addition the more fatigued an athlete gets during the run, the more the stride will become less efficient and the foot spends more time absorbing the force on the ground.

For recovery advice check eis2win.co.uk after the race

Photography © Getty Images