Training in the heat, what should you think about?

A few days a week I go for long walks here in Pattaya, just to get in shape. Others visit the numerous gyms, jog on Pratumnak Hill or in a park and still others play badminton or other sports. Sports in the tropics require some precautions to prevent unpleasant consequences.

There are numerous websites that provide information about the precautions to be taken, but those websites are mainly aimed at competitive runners such as a (half) Marathon. Yet I also learned something for us, simple athletes in Thailand. Below are a number of tips that appeal to me personally.

General

Preferably train in the morning or evening and try to avoid the hot afternoon. Wear airy clothing that allows evaporation of sweat to cool the skin. The color of the clothing is also important. Light colors will reflect the sun's rays and therefore absorb less heat. Dark colors, on the other hand, absorb the sun's rays, which means they absorb heat.

In heat, run at a slower pace than you are used to and run fewer miles. This is especially important when you are not very well trained. Walk on forest floor or grass. This is considerably cooler than walking on asphalt where the heat is reflected back.

In hot weather, take frequent drinking breaks, even when you are not thirsty. Thirst only occurs when your body has already lost (too) much fluid. Being thirsty or not is therefore a poor indicator.

The heartbeat

In warm weather, the individual heart rate zones are higher than normal. This effect is not only temperature dependent, but also dependent on the humidity. The higher the humidity, the greater the increasing effect on the heart rate.

Due to the higher body temperature, the blood vessels in the arms and legs open more. As a result, part of the total blood volume moves to the extremities. This results in a reduced filling of the heart, so that less blood is pumped around per heartbeat. To compensate for this, the heart rate increases so that the amount of blood that is pumped around remains the same.

In addition, dehydration occurs more quickly in hot weather because a lot of moisture is lost through increased sweat production. This causes the blood volume to drop, which also increases the heart rate.

The effect of the heat on the heart rate is not equally strong for everyone. Some runners will barely notice a difference, while others will have a 10-15 beats higher heart rate zone.

Possible consequences of training in hot weather

Kramp
Painful contractions of the skeletal muscles cause cramping, usually in the calf muscle. This is the result of extreme fluid loss, which disrupts the balance between the salts in the body cells (sodium, potassium, calcium).

Collapse
A temporary, partial (fainting) or total loss of consciousness (collapse) is caused by the accumulation of blood in the lower extremities. This causes blood pressure to drop and loss of consciousness to follow. Persons who remain immobile for extended periods of time in the heat, such as line judges and spectators, are at risk for this condition

Sunstroke
Symptoms of heat stroke (heat exhaustion) are severe fatigue, dizziness, headache and skin that is soaking wet with sweat. Heart and circulation have a hard time. This is because skin circulation is increased to dissipate heat, while circulating volume is reduced due to moisture loss through sweating.

hyperthermia
Hyperthermia (heat stroke) is a life-threatening condition. When the heat stays on and the loss of moisture, the skin circulation decreases in favor of the central circulation. The body temperature can then rise extremely. Symptoms include hot, dry skin, rapid pulse, and irrational behavior. Sometimes it can even lead to convulsions and fatal damage to the nervous system and internal organs.

Tips to prevent conditions in extremely hot weather

1. Sweat must evaporate

Sweat can easily evaporate if the clothing is made of light, breathable and loosely woven material, such as cotton. Change shirts regularly, so that you do not have to work out in soaked clothing. Wristbands are useful for keeping the palms dry and a headband can keep the sweat out of your eyes.

2. Protect from the sun

Ultraviolet rays (UV), both UV-A and UV-B, can damage the eyes and cause skin cancer. A cap keeps the head cool and protects the face and neck from burning. Against the bright glare of the sun, sunglasses or dark contact lenses are not a superfluous luxury. In the longer term, this is also better for the eyes. The skin can best be protected with a sunscreen with a good protection factor (BF) or Sun Protection Factor (SPF). It is recommended to use a minimum factor of 10 to 12 in the Netherlands. Clothing is preferable to sunscreen. In the summer, the sun is highest between 12 and 3 am and there is more UV radiation. It is therefore best to exercise in the morning or in the evening. 

3. Sufficient moisture

Make sure to drink enough. During short-term efforts, for example an hour-long workout, drinking water is a good way to replenish fluid loss

5. No salt tablets

In the past, salt tablets were sometimes recommended on warm, hot competition days. However, don't do this. While it is true that sweat contains salt, using salt tablets is similar to drinking sea water when you are thirsty. It only exacerbates the problem. Drink plenty of fluids and supplement the loss of salts with the natural salt of your diet.

6. Take a break

During training sessions in the heat, ample use of breaks (thirty minutes of play, twenty minutes of rest) is recommended. Cool the face with cold water. The body also cools down from a wet towel on the neck.

7. Chance of recurrence

People who have had problems with the heat in the past are at a higher risk of a recurrence and would be wise to keep exercising in the sun to a minimum. Children, the elderly, the sick and less fit people are at greater risk of heat disorders. It is better for them to avoid situations of extreme and prolonged heat.

Finally

I think it is useful advice that is written for athletes, but people who work outside for a long time, for example in the rice fields or doing jobs outside the home, can also benefit from it.

Source: RP© ProRun