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Behobia / San Sebastián official website - 58 Edition

58 Behobia - San Sebastián 2023

BSS Salud


To demonstrate the influence of heat on performance we compared the times in 2014 when the temperature was 13º-14º and the humidity 68% with the times in 2015 when the temperature was 27º-29º and the humidity 40%.

Comparing the average time of all the participants in 2015 with those in 2014 you can see that in the 2015 edition it took an average of 8 minutes and 27 seconds more to complete the race than in 2014.  If we analyse this time loss at each timing point, we see that the loss in time was not constant.  In the stretch Start-km 5 only 45 seconds were lost , in km 5-10 one minute and fifty-eight seconds were lost, in km 10-15 two minutes and twelve seconds were lost and in the km 15-Finish the time lost was 3 minutes and 32 seconds, nearly 5 times more than in the first stretch.  


The conclusions drawn from this data is that the participants in general started out with the idea of fulfilling their objectives, straining themselves to do so without bearing in mind the effects of heat on the organism.  For this reason in the first 5 km only 45 seconds on average were lost, representing 9 seconds per km.  In the next 5 km, 23.6 seconds were lost per km, as the pace stabilised, increasing slightly to 26.4 seconds per km from the timing points km10-15 and finally faltering due to the initial effort and losing up to 42.4 seconds per km, nearly 5 times more than in the first stretch. 

Bearing in mind that the average loss of time at the Finish was 8 minutes and 27 seconds and bearing in mind that the ideal would be to maintain as steady a rhythm as possible, the loss per km would be 25.35 seconds.  So, from the data it can be deduced that participants in the last stretch paid for the efforts made in the first leg of the race.


Heat can be one of the greatest dangers for any athlete, especially if they exercise intensely.  In the last few years of the Behobia-San Sebastian race, we have observed a considerable increase in the number of participants when the ambient temperature is above 20 ºC.


Heat can affect the organism at different levels of severity.  If during the race you notice malaise, cramps or dizziness, stop running, ask for help.  Do not insist on continuing, this will only worsen the situation.   There is a health unit that will come to your aid quickly, but the best measure is prevention.  Below is a brief summary of the effects of heat on the organism.

Muscle cramps.

These are muscle contractures due to excessive loss of water and salts, and an increase in temperature.  They could be the first symptom of a more serious problem.  Please stop and ask for help.

Heat syncope.

This is the loss of consciousness (fainting) that you regain quickly by lying on the ground.  On occasions you don't lose consciousness completely, but you notice malaise, dizziness or instability.  It means that the loss of liquids or salts is more serious, and the effect of the temperature is greater on the organism.  You should cease the activity immediately and ask for help. 

Heat exhaustion.

Incapacity to continue running, together with dizziness, malaise, nausea and vomiting.  You should stop immediately and request medical assistance.

Heat stroke.

This is the most serious scenario within the possible effects of heat on the organism.  There may be cerebral, renal, muscular and liver  dysfunction,  and this calls for immediate attention to avoid serious injury or even death.  During the Behobia race last year, the most serious calls were for Heat Stroke.  Heat Stroke is related to the ambient temperature, the degree of humidity and the pace of the race, and not directly with the physical condition of the person, with cardiovascular problems, or with the level of hydration.

Our organism has the capacity to eliminate heat from the body. To do so, it has four mechanisms: evaporation of sweat (primarily during exercise), heat irradiation, conduction and convection (the latter two influenced by wearing non-breathable clothing). If the ambient temperature is high, the basic mechanism is sweat, and the capacity to eliminate heat is limited.  It is, therefore, important to know the factors that influence the effect of heat:


1. Personal propensity. Some people are more susceptible to suffering from heat during exercise.  If a person has had similar problems before, they should be studied in depth before doing physical exercise.

2. Lack of rest.  You should not undertake a race like the Behobia-San Sebastian without having slept a minimum of 7 hours the night before.

3. Concurrent illnesses: colds, gastroenteritis, etc.  Suffering from any of these increases the risk of having a serious problem due to heat if you do physical exercise. 

4. Obesity.

5. Little training.

6. Lack of acclimatisation.

7. Dehydration.


1. High ambient temperature.

2. High air-humidity.

The organisation will give news of the ambient conditions prior to the start.  A hot humid day is not a day to improve results.  Run at a slower pace and avoid unnecessary risks.  Do not look at your watch.  Avoid overexertion.  Use a heart rate monitor.

Taking drugs and/or medication.

Taking drugs and/or pharmaceutical drugs may increase the risk of suffering a health problem due to heat.  You should avoid alcohol, amphetamines or other drugs, and if you take diuretics, beta blockers or other cardiovascular drugs do not run in the race.  If you are taking any other drugs, consult beforehand.

Preventive measures.

Before the race.

Find out about the weather forecast for the day of the race. The organisation will also give this information.   If high temperatures are expected, get prepared mentally to maintain a slower pace.

Rest properly and sleep seven hours minimum the night before the race.  Avoid alcohol and other drugs.

Do not race if you have a cold, gastroenteritis or other illnesses.

During the race.

Hydrate adequately (neither too much nor too little, what your body demands) at the stands located for this purpose.

Do not become obsessed about keeping up a running speed or improving your time.  If the temperature is high, this could lead to serious problems.  If you notice you are exerting yourself, slow down the pace of the race.  A forced rhythm over various kilometres  could lead to serious consequences.

If you notice cramps, dizziness, malaise or headaches, stop and ask for help.  There is a health attendance service that will come to your aid quickly.  The race will still be there next year.  

Signs and symptoms questionnaire

Corazón hecho con cordones de zapatillas deportivas

Acceso al cuestionario


Sportsmen and sportswomen are the healthiest members of our society and have a much lower risk of contracting cardiovascular diseases, some cancers, diabetes and dementia than people of the same age who do not sport. This is due to the fact that frequent physical exercise reduces considerably the risk of contracting many diseases among old people such as heart attacks, angina, heart failure, strokes, high blood pressure, obesity, type II diabetes, osteoporosis, arthrosis, and rheumatoid arthritis, several types of cancer, depression, dementia, fibromyalgia and dependency.

Moreover, physical exercise is a very good tool, sometimes the best, to treat all these diseases, once they have been diagnosed. For this reason, many Scientific Associations and Public Institutions recommend and promote physical exercise among people of all ages.

Deshidratación y deporte


La deshidratación es un trastorno que ocurre cuando una persona pierde más líquidos (por ejemplo, en forma de orina o sudor) que los que ingiere. Cuando una persona se deshidrata, significa que la cantidad de agua que contiene su cuerpo ha descendido por debajo del nivel adecuado (nuestro cuerpo contiene aproximadamente dos tercios de agua). Las pequeñas pérdidas de líquidos no representan ningún problema y en la mayoría de los casos pasan completamente desapercibidas.


Pío Baroja, 47 - 20008 Donostia / San Sebastián (Gipuzkoa)
T. 943 314 859

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Luanvi TotalEnergies Rural Kutxa
Kaiku Forum Sport Campos Quironsalud Policl�nica Gipuzkoa

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