What do you notice happening to your body when you exercise? The list would probably go something like this:

• Your heart beats faster
• You breathe more deeply and more frequently
• You sweat and feel hotter
• You feel thirsty
• You change "colour" - your skin becoming "flushed"
• You can feel your pulse beating
• Your muscles may begin to ache
• You may feel light headed and not as mentally alert

Obviously the body is trying to tell you something. There has to be a purpose to these changes or else the body would not bother. It is saying "If you are going to be doing this, I need extra resources". Let's take a look at some of the clues.

Fact - Your heart is a muscle and its function is to pump blood around your body. Blood is the transport system for your body and carries the fuel and nutrients your body requires. Your heart is approximately the size of a clenched fist and weighs about 300g. It also holds about 70ml of blood (4.5 tablespoons) or about 1ml for every kilogram of your body weight. At rest your heart rate averages about 72 beats per minute so the amount of blood being pumped around your body each minute is 70 x 72 = 5 litres.

Fact - During moderate exercise, such as steady running during a game, your heart will respond to the increased demands for resources by slightly enlarging, thus allowing more blood to enter your heart, and by increasing the number of beats per minute. This allows more blood to be pumped around your body i.e. 80 x 130 = 10.4 litres. As the intensity of your exercise increases e.g. you have to sprint, heart rate increases still further so more blood can be circulated e.g. 80 x 170 = 13.6 litres.

Reason - Your body is asking for deliveries to be increased to meet the new demands. With nearly three times the volume of blood flowing around your body it cannot be surprising that awareness of your pulse beating is also enhanced. Because of the greater volume and the increase in the speed at which your blood is flowing, your heart would have to pump harder, and your blood vessels expand, to meet the demand. Your heart is beating more strongly so you feel the blood pulsating.

Thought - An Olympic athlete can reach a level of 40 litres per minute!

The message here is quite simple. Your body is asking for more oxygen to cope with the demand for a greater fuel supply to your working muscles.

Fact - The oxygen you require is breathed in through your nose and mouth and passes down your bronchial tubes and into your lungs which are made up of over 300 million tiny air sacs called Alveoli. It is here the oxygen transfers itself to your blood to be transported around your body.

Thought - If you were to flatten out the surface of your lungs it would cover an area of between 150-300 square metres.

Bearing in mind only 80ml of blood is circulated per beat of your heart during exercise, that is a lot of surface area over which to spread such a small amount of blood. It means the blood can be spread very thinly and this speeds up the transfer of oxygen.

Thought - Put another way, one person getting onto a tube is quicker than 30 people trying to get aboard during rush hour!

Fact - When resting you usually breathe in about 500ml per breath and you do this 12 times per minute. This would give you 6 litres of air. When you are exercising it is quite reasonable to take in 2300ml per breath and your breathing rate could increase 2 or 3 times.

Thought - This means you would be taking in up to 80 litres of air.

How you breathe is also very important to you. Is it better to take slower deeper breaths or faster shallower breaths? The answer lies in understanding the mechanics of breathing.

Fact - When air is taken in, a small amount (150ml) remains in your air passages and never reaches your lungs. This is known as the 'Dead Air Space'.

Say, in slow deep breathing you were to breathe in l000ml of air, the amount of air reaching your lungs would be 1000 - 150 850ml. If the number of breaths per minute is 16, the total air breathed in for one minute is 1000 x 16 = 16 litres. The total air reaching your lungs, however, is 850 x 16 = 13.6 litres.

By halving the amount of air breathed in and doubling the number of breaths per minute as in faster shallower breathing, the total amount of air taken in remains the same i.e. 500 x 32 = 16 litres.

However, the amount of air reaching your lungs is greatly reduced. 500 - 150 = 350 x 32 = 11.2 litres (instead of 13.6 litres).

Advice - Slow deep breathing is more efficient than rapid shallow breathing in increasing air flow to your lungs.

Fact - When you exercise the muscles are used more and as a result produce heat. This heat needs to be dissipated and your body loses heat in two principal ways. Firstly, your sweat glands are stimulated to secrete fluid, which then evaporates on the surface of your body to produce a cooling effect. Secondly, your small blood vessels near to the surface of your skin enlarge to allow more blood to flow closer to the surface where cooling can take place. This is what makes you feel "flushed". Your body is telling you it wants to cool down so you should help it.

Thought - The mere process of sweating is not in itself a cooling process. The liquid sweat must be allowed to evaporate before any heat loss occurs.

Advice - On a hot day you should try and wear a short-sleeved shirt, or at least have the sleeves rolled up, to allow more skin surface to be exposed to the air.

Fact - Exercise will increase the temperature of your body and your body will try to reduce the temperature by secreting fluids. These fluids come from the reservoir of fluids contained in your body. lithe fluids are not replaced the level in the reservoir will go down and eventually this will trigger a feeling of thirst.

Thought - Thirst is a poor indicator of fluid needs as by the time the feeling of thirst has been registered the level of your reservoir is already quite low. Prolonged periods of intensive exercise can result in fluid losses of up to 2-3 litres. This results in dehydration which will not only adversely affect performance but can also be dangerous.

Advice - Fluid, especially water, should be regularly consumed before, during and after training or matches to continually top up your reservoir and prevent you feeling thirsty.

So far, the reason for all this activity by your body has been to ensure your muscles receive an adequate supply of fuel and nutrients to enable them to work and propel you around the field of play. One of the by-products of all this activity is heat, but there are other waste products as well to be dealt with.

Fact - In moderate exercise your body may be able to remove these waste materials as they are produced, but as the intensity or length of the activity increases, the build up of these waste products occurs faster than they can be removed. The waste materials occupy space previously available to the fuel and nutrients in your blood, so as they build up, your blood supply to carry them away decreases. Without oxygen and nutrients the efficiency of your muscles diminishes, waste products swell your muscle, and muscle soreness ensues. 

Reason - Your body is telling you it is getting tired and will soon need a rest. The fitter you are the longer you will be able to exercise before the waste products begin to swell your muscles.

Tip - When such soreness occurs, stretching the muscles involved will assist in reducing the pain and discomfort.

So far, you know the reason for all the changes occurring in your body are related to getting more fuel and nutrients to your working muscles. In most cases in life when demand increases, additional resources are sought and brought into play to meet the demand. Blood is your transport system but you cannot suddenly inject a few extra pints, you have to use what is already there.

Fact - When you are going about your everyday lives, blood is circulating to all parts of your body. When demand increases for more fuel to be taken to working muscles, your body responds by reducing your blood supply to some organs not immediately involved in the activity. It is then redistributed to the areas in need. This means that organs such as your liver and stomach will have their blood supply reduced so that more blood can be taken to your muscles.

Thought - It is unwise to eat a lot of food prior to exercising, as with a reduced blood supply the food cannot be broken down and carried away quickly. It remains in your stomach longer and can cause nausea and stomach cramps.

Fact - Your brain is another part of your body that finds itself having to deal with a reduced blood flow and the diminished oxygen supply may well make you feel light-headed and cause your concentration to lapse. In severe cases it could cause you to collapse.

Tip - The fitter you are the more efficiently the oxygen can be transferred to your muscles. As the oxygen flows to your muscles more easily they get all they want without having to call on all your extra supplies of blood. Oxygen reduction to your brain is, therefore, decreased.

No you don't, but at least you know what your body is trying to do to help you referee.

Thought - Why not support your body and make refereeing a joint effort. You will become a better referee if you and your body practise together. With practise your body will perform its tasks better, leaving you to concentrate on performing well as a referee.

Advice - Ignore these requests at your own peril.


WHAT DO YOU NEED TO PRACTISE?

Running - for sure.

Did You Know? - A referee covers between 6 and 12 kilometres during a game depending on the level of the competition.

Fact - Research carried out at Liverpool University in 1993 on 11 Football League Referees and 3 Contributory League Referees showed that they:

• Covered 9-10km during the match
• Had an average heart rate of 165 beats per minute
• Spent the major percentage of the time with heart rates above 85% of their maximum
• Varied their movements around the field to include 50% jogging, 20% walking, 20% reverse running and 10% sprinting.

Tip - This is valuable information and should be used to help you devise your training programmes.


(I) DISTANCE

There is nothing wrong with going for a run, but it is of little use if you do not run very far.

Tip - If you are expected to cover between 6 and 12 kilometres during a game then you should practise covering those distances during training.

(ii) INTENSITY

You are told that your heart rate is likely to rise to about 165 beats per minute and that for the major part of the game you will be working near to 85% of your maximum heart rate. To get benefit from this information you need to understand something about heart rates. What is your maximum heart rate, for example? Will your heart be able to cope with 165 beats per minute?

Fact - It is generally accepted that a person's maximum heart rate is equivalent to the formula 220 - Age = Maximum Heart Rate. So a young, healthy 20 year old referee could expect to have a maximum heart rate of 200 beats per minute. If this referee had a heart rate of 165 beats per minute during a game, then that would correspond to 82.5% of the maximum heart rate.

As you can see, a 55 year old referee working at 165 beats per minute would be working at or near the predicted maximum (220 - 55 = 165). The body would not be able to maintain this level for the duration of the game and so our referee would have to slow down to allow the heart rate to drop. Having said that, a referee who has trained hard over the years would have been able to slow down the rate of normal decline and even at the age of 55 years could still record a maximum heart rate well above the predicted value.

Thought - This may help to explain why some older referees are still fit enough to continue performing at the top.

Advice - During training you need to practise raising your heart rate to the level it is likely to go during a game. Jogging along slowly and steadily for 8 kilometres may cover an appropriate distance but not at the right intensity. You need to check your heart rate has increased to near match level by stopping every now and again to take your pulse. During training you should aim to increase your heart rate to between 70% and 90% of your maximum. (See Heart Rate chart below.) If your heart rate is below 70% you are not running hard enough but if it is over 90% you should ease off a little.

(iii) VARIATION

Refereeing is not just about running up and down. During a game you would be expected to move in a variety of ways including jogging, fast running, sprinting, sideways running, running backwards, walking and even standing still. If that is what is required then surely you must practise these movements.

Tip - Running is a good basic stamina builder but you need to include the other movements so your body gets used to it.