Hiking in warm conditions

1. Sweat needs to evaporate
Wear light, breathable clothing made of loosely woven material, so that sweat can evaporate easily. Black and dark clothing actually increase the risk of overheating. With a headband you can keep sweat out of your eyes.

2. Protect against the sun
UV rays can damage the eyes and cause skin cancer. With a cap you keep your head cool and protect your face and neck against sunburn. Sunglasses are useful in bright sun. Also do not go out without protecting your skin with a sunscreen with a good Sun Protection Factor (SPF).

3. Air temperature and WBGT
Maybe a light bulb doesn't go off here right away. The air temperature gives an indication of the 'heat stress' to which the body is exposed. The WBGT (Wet Bulb Globe Temperature) is an accurate method to measure this, because it also takes into account humidity, wind, and radiation from the sun. For sports associations, the WBGT is a good guideline to determine whether events can go ahead or whether extra measures need to be taken.

4. Drink enough, but in moderation!
Fluids and water are the most important points of attention at high temperatures. But only drinking water is not enough, because when you sweat you also lose salt. This can cause a deficiency of salt in the blood, which can lead to problems. Therefore, alternate water with sports drink: this actually contains salt.

The most convenient thing is to know about yourself approximately how much you sweat during walking; because this can be very different per person! But how do you find out how much you actually sweat? Then step on the scale occasionally before and after a training session. Try to drink enough so that you have not lost more than 2% of your body weight afterwards, but also not so much that you weigh more afterwards.

Now you also know approximately what you need in terms of water during the event. With the last meal – about 2 hours before the event – take two large glasses of water (500 ml). Now your body has the time to absorb it, but you can also still get rid of the excess water. Take some extra salty foods if it is really hot. People get into trouble sooner from overheating than from dehydration. But dehydration does make you overheat more quickly. So throw water on your body and sports drink in your mouth!

Below are some additional tips about fluid intake:

• Always drink large sips at a time, frequent small sips stimulate the stomach less well, making gastric emptying slower;

• Preferably bring water yourself as well;

• Do not drink alcohol before the run;

• In general: your urine production must be sufficient (at least 1.5 liters per day). By looking at the color of the urine, you can check if you have drunk enough. Before the event, the urine should preferably be light yellow. If the urine is dark yellow, you have drunk too little.

5. No salt tablets
In former years, salt tablets were sometimes recommended on hot event days, but we have left that time behind us. It is correct that sweat contains salt, but using salt tablets is comparable to drinking salt water: it only makes you thirstier. Drink plenty of fluids and replenish salt loss with the salt in your food.

6. Adjust your pace
You may have trained to walk at a brisk pace, but you would do well to adjust your pace in warm conditions. Start controlled and check your pace. Walk/cycle your own pace and avoid major pace changes during your participation.

7. Use a Red Cross post
On the route of the event you will find posts of the Red Cross. You can go here if you do not feel well or suffer from something else. Should you recognize one of the symptoms of heat stroke as described above in yourself, stop immediately and seek help at a Red Cross post. It is also possible that the athlete does not recognize the symptoms in themselves; so also take a look at your fellow athletes. Do you see them staggering? Bring them to the side and let them lie flat in the shade and ask for help.

8. Clothing
In order to be able to lose excess body heat properly, the right choice of clothing is of crucial importance. Therefore, make sure that you do not skimp on clothing, but make use of high-quality clothing. The following tips will come in handy here:

• Do not dress too warmly and choose clothing that limits the evaporation of sweat as little as possible. So use 'breathable' clothing;

• On the day of the event, do not expose yourself too much to heat, so no warm clothing; 

• White clothing has the best reflection of heat from the environment, in contrast to black clothing. White clothing is therefore preferred;

• Protect your head and neck when exposure to direct sunlight is unavoidable (breathable headgear); 

• Preferably use sunglasses to protect your eyes from bright sunlight.

Take off your sweaty clothes as soon as possible after your event and put on clean and dry clothes. This is important because the moisture in your sportswear cools down quickly and as a result your muscles can also cool down quickly.

9. Chance of recurrence
People who have had problems with the heat before have an increased risk of recurrence. If you are someone who has experienced that before, be extra careful with exercising on hot days. In general, children, the elderly, the sick and less fit people always have an increased risk of heat disorders. They had better avoid situations of intense and prolonged exertion in the heat.

10. Acclimatization
Try to do a training session on a hot day in preparation for a walking event in spring or summer. This can help you learn how your body reacts to the heat and what signals it gives. It also allows you to let your body get used to exercising in warm conditions (acclimatization) so that it is better prepared for potential heat during your walking event.

Tips from the Red Cross
The Red Cross conducted a survey among sporting Dutch people and the conclusion was that to possibly prevent overheating, signals from the body should not be ignored. Read here on their website some advice and results of this study.