To:
All participants of Venloop 2014
Venray, March 2014
Dear runners,
The 9th edition of the Weir minerals Venloop is about to commence. On 29th March the walkers will hear the
starting signal on their 25 or 40 km walk and there is a race for those in wheelchairs of 6.5 and 10.5 km
respectively. On 30 March the runners will embark on distances varying from 500m for the Bambino run and
Child run to the ½-Marathon.
The risk of injuries or other medical problems is always higher during races than at normal running practice. As
medical partner of Venloop, Sport Medisch Adviescentrum Vitaal gives a number of tips and interesting facts
below in order to be properly prepared for the start.
Weather
The weather conditions can have a major influence on the functioning of the body and therefore on the
performance of the participants. The outside temperature, the wind and humidity can have a major influence on
the performance. It is therefore important to keep an eye on the weather forecast and to respond accordingly.
The weather in the Netherlands is (generally) cool and wet at the end of March, but there is also a chance of
warm and sunny weather. The weather conditions can also change during the race. It is therefore important to
bear this in mind when choosing your running clothes. In addition, the amount of fluid required during the race
can vary greatly with the outside temperature and the wind. The effect of a warm sunny day is generally much
greater if the prior period (in which the training occurred) was significantly cooler.
Fluid
The water balance of endurance athletes is essential. During a half marathon the runner can sometimes lose
more than 3% of their body weight through sweat and urine production. From 2% of fluid loss (this is ‘only’ 1½
litre for the average runner) a demonstrably reduced performance is already present. In more extreme cases
(>6% of the body weight) there is a risk of exhaustion, unconsciousness and even coma. Each year runners and
other endurance athletes – primarily in the summer months – are hospitalised as the result of a shortage of fluid.
It is therefore important for endurance athletes to ensure the intake of adequate amounts of fluid during the
race.
Too much fluid, especially excessive amounts of normal water, can also cause problems during a half marathon!
Excessive amounts of only water can result in a relative salt shortage in the blood. A salt shortage (too little
Sodium) will also reduce the performance and can pose a (serious) health risk. It is therefore of major
importance during the race to not only being aware of the correct amount, but also the correct composition, of
the drinks.
What is the correct amount? In general it can be stated that drinking when you are thirsty will not lead to serious
dehydration or a shortage of salt. However it is true that thirst only occurs when there is already a shortage of
water. This shortage of fluid can result in a reduced performance. When running for longer than one hour and an
outside temperature in excess of 15 degrees Celsius it is – certainly for the less well-trained runners – advisable
to drink despite not feeling thirsty. The average fluid requirement during intensive endurance sport can vary
wildly from individual to individual and is between 500 and 1000 ml per hour.
There are a number of notes concerning this.
 Warm weather with a high level of humidity results in a higher loss of fluids and the chance of
dehydration is greater.
 Slower runners, who are underway for a long time and drink a lot of water, run a higher risk of a relative
salt shortage (hyponatremia).
 Also when it is cold – and even when frosty – there is still a loss of fluid which needs to be suppleted.
 Sweating in an important bodily mechanism to keep the core temperature low. It is not advised to block
the evaporation of sweat with clothes that are (too) heavy or waterproof. Under moderate conditions (15
degrees Celsius) it is also possible that the bodily temperature during a half marathon rises to 39
degrees Celsius. This can easily rise even higher when you are wearing too many clothes or clothes
that block the evaporation of sweat.
 On the other hand a sweaty runner can quickly cool off if the running is interrupted by periods of walking
and/or standing still for any reason.
During the Venloop there are drinking stations every 5 km to give the participants the opportunity to keep
sufficiently hydrated. It is very unwise – and rather unnecessary in view of the distance between the drinking
stations – to accept drinks from others without knowing for certain what it is.
In terms of the composition it is best to opt for a combination of normal water and thirst-quenching sports drinks
(also refer to the Food section below).
Many runners who drink while running suffer from an annoying bloated feeling in the stomach. Research has
shown that this generally occurs when small sips are taken. The stomach is the not given an adequate signal to
empty itself. It is recommended to drink an amount of 200-250 ml in one go at the drinking stations.
It is good to drink a little extra prior to the start, but in sufficient time before the race (approximately half an hour)
and not excessive amounts (approximately 250-300 ml)
Food
Food is as crucial when running an endurance race. The most important fuel during intense physical activity is
the store of carbohydrates which are already in the body. Carbohydrates are stored in the liver and in the
muscles. This store is (on average) adequate for approximately 15-20 km regardless of the speed of the runner.
For a maximum store of carbohydrates, people can eat slightly more carbohydrates in the days before the
marathon (grain products, pasta, rice, sweets) and at the same time limit the duration of the training.
Carbohydrates are absorbed best into the body when they are consumed with protein (dairy products, meat,
fish, nuts, etc.). The training in this period cannot be exhausting anymore. It makes no sense to eat a large
amount of carbohydrates (pastas) the night before the race. This often causes gastrointestinal problems on the
day of the race.
It is important to also replenish the energy stocks during the race. Try to do this with carbohydrate-rich food
products such as energy bars and bananas. Use the guideline of approximately 1 gram of carbohydrates per
kg of body weight per hour. For a runner of 80 kg this amounts to 80 grams of carbohydrates per hour. More
than 60-80 grams of carbohydrates per hour cannot be absorbed by the body. The absorption of food during
(intense) physical exercise is very limited. The intake of extra solid carbohydrates is only worthwhile in the first
half of the race.
Sports drinks (energy drinks) that are too concentrated retain fluid in the stomach and intestines. This can result
in nausea and diarrhoea and blocks a rapid uptake of fluid from the intestines.
Research has shown that liquid carbohydrates have a better uptake than solid carbohydrates. The average
commercial thirst-quencher (sports drink) contains precisely 60-80 grams of carbohydrates per litre, which can
be absorbed by the body during the exertion. It is not good to consume energy drinks during the exertion,
because its carbohydrate (sugar) concentration is too high. Often this results in the drink remaining in the
stomach or the intestines for a long time, causing nausea and/or diarrhoea. Because fluid and carbohydrates
require some time to be absorbed by the body from the stomach and the intestines and to become available to
be burnt in the muscles, the intake of fluid and energy is far more important at the start of the race than at the
end.
Injuries / sickness
Injuries occur in every sport and running is unfortunately no exception. Many injuries or problems during the
race however can be prevented by taking simple preventative measures.
The most common problems are listed below.
 Skin problems
One of the most frequently occurring problems during a marathon is blisters and/or scrapes. The strain from
running can cause the foot to chafe along the shoes resulting in blisters and scrapes. Places where the skin
comes into contact with the shoes or clothes (for example the heel, the nipples (men), the groin, the anal seam,
the front of the armpits can be protected against chaffing with Vaseline or are plaster (nipples). This can often
make running more comfortable. If possible wear running socks without irritating seams and preferably no cotton
socks which absorb much water.
Wear sufficient sunblock in sunny weather. Preferably do not opt for greasy creams or oil.
 Muscle and tendon complaints
Muscle and tendon complaints also occur frequently. This can vary from a strained or pulled muscle to straining
the Achilles tendon, for example. Generally with tendon issues this concerns a recurrence / worsening of an
existing complaint. If you experience an injury during a race it is not advisable to continue. You will run the risk
of making the injury worse, to such an extent that you will be injured for a longer period of time.
 Muscle cramps
Muscle cramps occur primarily after completion of the race or in the final part of the race and are often a sign of
exhaustion and/or lack of fluids.
 Recent sickness
A recent period of sickness – certainly if it concerns fever – can have a major effect on one’s condition. Often a
period of 2 weeks is required to get back to the old level following a period of fever. If training in the weekend
prior to Venloop can be resumed without issues then participation is fine. It is extremely unwise to participate in
a race if the symptoms are not fully gone, or have gone only a few days ago. In case of doubt please consult
your GP for advice.
It is advisable to consult a sports doctor, GP or physiotherapist in case of injuries that have occurred just prior to
the race.
Sudden cardiac death
Thankfully heart complaints and sudden cardiac death do not occur very frequently with athletes! The chance
that you experience (unexpected) heart problems during a race are therefore small. Despite this, every year
there are a number of runners who experience heart problems in the Netherlands when running. If you
experience one or more of the below symptoms during or after the race, it is advisable to request medical
support.
The symptoms are:
shortness of breath (other than due to poor condition),
chest pain, sometimes radiating to the arm, throat or jaw
heart palpitations, irregular heart beat
dizziness / feeling faint.
In the case of injuries and other medical problems during the race, the medical personnel present will advise
you whether it is possible to continue the race with the problem that has occurred. In some cases the medical
assistance can issue non-negotiable advice to the organisation to remove a runner from the race. This only
occurs in case of problems which would pose a serious risk for the runner.
Contact details and medical data
If you have known medical problems and/or use medication, it is essential that you carry something with you
with information about the present sickness or the medicines you use during the race to allow adequate care to
be provided.
All runners are advised to write their contact details (name, address and telephone number of a contact person)
on the back of their starting number in order that medical assistance knows who they should contact or where to
find additional information in the case of an emergency.
For additional questions or for the assessment of injuries in the final preparation period or injuries as a result of
participating in the Venloop, please contact SMA-Vitaal on +31 (0)478-522777, info@viecurivitaal.nl, Twitter
@Sportvitaal and www.smavitaal.nl.
We hope that you will enjoy a wonderful 9th Venloop and we wish you a pleasant race!
Rob Eijkelenboom, SMA-Vitaal sports doctor
Medical Team VieCuriVitaal