Marathon Notebook - October 1984

For many people who complete a marathon it is the most meaninggful event in their lives. Successful completion of the 26-odd miles will be the result of months of hard, often lonely, endeavour. The run itself will bring enormous physioloogical and psychological stress that only the most completely prepared runners will overcome. Even after the months of preparation that have gone into training for the event the conditions and how the runner feels on the partiicular day will have a considerable bearing on how they perform. It is essential to be psychologically just as much as physically prepared for the event. Even the Olympic athletes admit to feeling an almost unbearable strain in the last few miles.
Marathon running is an aerobic activity, that is it depends on cardio-pulmonary efficiency. It relies on the amount of oxygen the runner can take up and use effectively. The hard training on the roads in the months leading up to a marathon are designed to increase this efficiency in the runner. The heart is muscle, and as with all muscles, can be enlarged. It acts as a pump, distributing oxygen to the muscles in the body, and the training increases the efficiency of the pumping mechanism. The fitter a person is the lower the heart-rate should be. If the training is working the heart rate should drop and it is advisable to check this regularly first thing in the morning on waking. Among the Olympic athletes in the Irish team at Los Angeles who were competing in aerobic sports like rowing, cycling and the marathon the average resting heart rate was about 40.

In the early stages of training the so-called LSD (long slow distance) is the means of improving the runner's ability to take up oxygen and distriibute it efficiently to the tissues. The term used for this is V02. The term V02 max is used to describe the maxiimum amount of oxygen the runner can deliver to the tissues per kilogram of body weight. The backbone of the training programme is the medium steady run. In order to gain the maxiimum benefit from training the runner should run at about 70% of his or her maximal efficiency. The length of time at which he or she can run at this level will increase gradually, and must do so. All progress in training must be a gradual process.

Energy for the muscles is produced by two substances, glycogen and free fatty acids. Although fat produces twice as much energy per gram in muscular activity it is less efficient than glycogen because it requires more oxygen for each calorie expended. In improving overall capability the glycoogen store is very important. During training it is important to train the body to efficiently metabolise both the sources, and to maintain a balance. Too high a dependence on either one of the energy sources will bring the exhaustion of the muscles about that much quicker.

Glycogen is produced from carboohydrates. The ideal diet for the average person is 55% carbohydrates, 30% fat and 15% protein with a minimum of 20 grams of fibre a day. The theory of glycogen loading has come into favour recently. This means that for a few days before the race, a runner's intake of carbohydrates increases to build up the glycogen levels. It is a commonly held view that for this to work best it is necessary to starve the body of carbohydrates for a week beforehand. This is not so. Merely increasing the intake of carbohydrates for a few days before running the marathon is usually sufficient. Carbohydrates are found in such food as wholemeal bread, potatoes and pasta. It would be difficult to sustain such a high proportion of the diet with such foodstuffs, so it is recommmended that a large amount of the daily intake should be through fruit drinks or fruit, both of which are rich in the necessary carbohydrates.

One of the dangers in training and in a properly balanced diet is that many runners tend to throw their diet out of synch by replacing the consiiderable amounts of energy they have lost with the wrong foods. It is common that runners will increase their intake of rich foods giving fat, which while it gives them energy, is not replacing the glycogen. This disturbance of the diet upsets the necessary balance beetween glycogen and free fatty acids on which optimum performance deepends.

A side-effect of the training is the so-called "runner's high".

This is an effect caused by the release of endorphins, naturally produced opiate-type substances in the blood. The effect, common with all activities of a rhythmic nature (for example, the chanting of mantras) usually occurs after about 35 minutes of steady, rhythmic running. It is a factor which could explain the popuularity of long distance running partiicularly in the case of those who are physiologically unsuited to it in the first place. It can also have rather disastrous consequences for those who become addicted to running. Witness the case of Dr Fixx, the father of jogging , who would appear from medical reports to have died from too much exercise when he had chest pains, a sign that the heart was not getting enough blood.

Although the term sounds as though it is a mental block, the causes are entirely physiological. At some point, usually about the twenty-mile mark in the marathon, most runners will experience the wall. The cause of this experience is that the muscles run out of glycogen, the essential fuel of the muscles. An end product of this breakkdown of glycogen is the production of lactic acid which brings on the pain and exhaustion.

In prescribing the diet for marathon trainers it is important to remem ber the fluid intake. 2% dehydration in the body causes a 20% loss of efficienncy. A high fluid intake is absolutely essential both during training and while running a marathon. It is posssible to lose 3 or 4 pounds in body fluid "during a marathon. On the day of the race itself the recommended intake is 600mls two hours beforehand and 400mls fifteen minutes before the race. It is vital that the liquid lost during the race be replenished so the runner should also take the proferred refreshment at every station on the route, taking small, regular sips from the drinks.

Even with all the physical preparaation and dietary controls, it is still likely that the average runner will come up against "the wall". In the January issue of The Runner magaazine, Professor William Morgan of the University of Wisconsin wrote of tests he had carried out concerning mental approaches to overcoming the phenoomenon. The attitude preferred by the professor and which he found was that preferred by most of the top class runners he had interviewed was that of association. This means that during the race the runner is totally aware of how his or her body is functioning and how it is reacting to the stresses placed on it. This consciousness allows runners to pick a pace which suits them and to increase or decrease the rate as his or her condition warrants. The problem for an inexperienced runner doing this, especially a runner who has never competed in a maraathon before, is that they cannot be so completely attuned to the working of the body nor able so accurately to assess the body's ability to overcome the stress the body is enduring. It also means, for a first time runner, that when the pain begins in the last few miles he or she will have no prior exxperience against which to gauge reacctions.

The alternative method used by runners interviewed by Professor Morrgan was dissociation. This method innvolves concentrating so intently on some external matter that the runner's consciousness is unaware of the strain and pain on the body. The dangers of this method are self-evident. In ignoring the signs of stress it is easy to ignore danger signals that signify disorders more dangerous than the simple effects of the wall. Dissociation is also less economical because the excess energy used in overcoming the strain through dissociation will have to be made up later.

It is important during training that the runners learn their best pace and the level of their endurance. Running within their capabilities is the best assurance a runner has of avoiding "the wall".

The only relevant piece of equipment is the pair of shoes you buy, and yet many people get it wrong. In choosing the shoes it is self evident that the important thing is that they fit properly. Because the foot swells in the course of the day it is advisable to buy the shoes at the end of the day so that the fitting will correspond to the shape of the foot during the run. The main points to look for in choossing the shoes are that they have good thick flexible soles; they have a good, stiff heel counter (the leather support for the heel) because if they are loose and do not sufficiently support the heel the fat under the heel can break up and cause a lot of pain; the tongue must be long and give adequate prootection to the foot because pressure from the laces can cause tendonitis.

The precautions to take in compeeting in a marathon are mainly selffevident. Do the hard work in training, and know before setting out what a realistic level of performance will be. Take sufficient liquid to prevent deehydration. Do not run on an empty stomach. Take a full meal five hours before and a light carbohydrate-based snack a couple of hours before the race. Don't take sugar shortly before the race. This causes insulin to circuulate in the blood which disturbs the metabolism of the free fatty acids which in turn depletes the energy reesources which will be used to the full in any event.

This article was prepared with the assistance of John Connolly, consulltant clinical psychologist, Dr Maura o 'Brien, the Royal College of Surgeons, and Mary McCreevy, dietician with the Irish Foundation for Human Developpment, all of whom worked with the Irish Olympic Council in preparing the Olympic team in Los Angeles.