Running in the heat: PREPARE, ADAPT, AND SURVIVE
RUNNING IN THE HEAT: PREPARE, ADAPT AND SURVIVE
The summer months are approaching, and days when temperatures easily exceed 30 °C under a blazing sun are not uncommon. Heat exhaustion, heatstroke or other heat-related problems can occur quickly and may even become fatal. Your approach to training or competing in endurance sports such as trail running, marathons, triathlons, cycling, etc. must change to take into account the real dangers posed by the heat. Knowing how to prepare and adapt properly is vital knowledge for anyone who practices an endurance sport. It may even save your life.
Here is a general guide and some basic explanations of the best ways to prepare and adapt your training:
WHEN REHYDRATING IS THE MOST IMPORTANT FACTOR.
Before, during and after exercise, rehydration should be your main priority in order to maintain fluid balance, especially during the hot and humid summer months. Therefore, your best option would be a hydrating sports drink diluted with water. Because most sports drinks contain a high amount of sugar, the liquid is not easily absorbed into the bloodstream. Mixing water and a sports drink half and half provides your body with the best combination of electrolyte replacement and immediate absorption. Products are also available that contain pure electrolyte concentrations that you simply add to water, such as ZERO tablets from HIGH5, Regeneration sticks from STIMIUM or capsules from GU Nutrition.
BEFORE: Many runners think about rehydrating after their run, and some drink water or sports drinks during the run, but it is just as important to be well hydrated before running. As a general rule, drinking 500 ml of water two hours before your run will ensure good hydration levels and give the water time to pass through your system so you do not have to make pit stops during your run.
DURING: Hydration during your run depends on the temperature and the length of your run. Do not wait until you feel thirsty before drinking. If you are thirsty, it means you have already lost too much fluid. Also, as you get older, your thirst mechanism is not as effective, and your body may be in the early stages of dehydration without you even feeling thirsty.
For the first 45 to 60 minutes, water is sufficient. After 60 minutes, you should start using a sports drink or supplementing with a sports gel or salty food such as pretzels. After 60 minutes (and sometimes earlier if it is very hot and you are sweating heavily), you begin to deplete essential electrolytes (i.e., sodium, potassium, etc.). Sodium is necessary for your body to absorb the fluids you consume. Have you ever experienced a “sloshing effect” late in a race? This is probably because your body is depleted of sodium and can no longer absorb the fluids you drink. You take in fluids, they remain in your stomach, but you do not absorb them and they “slosh” around. Depleted potassium levels can also increase your chances of experiencing muscle cramps.
AFTER: after finishing your run, water or a diluted sports drink is not the best choice for your recovery needs. Water and diluted drinks do not contain enough sugar and electrolytes for your body to restore its balance. Furthermore, because water or very diluted drinks are absorbed so quickly, consuming large quantities leads to an increase in plasma volume (in non-technical terms, this means your body is now saturated with water or diluted). This rapid absorption causes further electrolyte imbalance and frequent bathroom stops, which will only increase fluid loss and reduce your desire to drink.
Your best course of action after training is a recovery drink containing a good amount of sugar and electrolytes that will speed up your recovery process and stay with you a little longer ;-).
KNOW THE WARNING SIGNS
Dehydration occurs when your body loses too much fluid. This can happen when you stop drinking water or lose large amounts of fluid through diarrhea, vomiting, sweating or exercise. Not drinking enough fluids can cause muscle cramps. When you are dehydrated, you may become weak, nauseous and/or vomit, experience heart palpitations and/or dizziness.
Runners, cyclists and other endurance athletes should also be aware of the signs of severe dehydration, such as heat exhaustion and heatstroke. This is not only for your own safety, but also so that you can identify the symptoms if another runner experiences heat-related problems.
Heat-related effects of exertion can take several forms.
What you should do depends on what you are experiencing:
Heat cramps
- Cause: dehydration causes an electrolyte imbalance
- Symptoms: severe muscle or abdominal cramps
- Treatment: restore salt with foods or drinks containing sodium
Heat fainting
- Cause: often caused by a sudden stop that interrupts blood flow from the legs to the brain
- Symptoms: fainting
- Treatment: after the fall, elevate the legs and pelvis to help restore blood flow to the brain
Heat exhaustion
- Cause: dehydration causes an electrolyte imbalance
- Symptoms: core body temperature of 38.5°C to 40°C, headache, fatigue, heavy sweating, nausea, clammy skin.
- Treatment: rest and apply a cold pack to the head/neck; also restore salt balance with foods and drinks containing sodium
Hyponatremia
- Cause: excessive water intake dilutes blood sodium levels; usually occurs after four hours or more of exertion.
- Symptoms: headache, disorientation, muscle twitching
- Treatment: emergency medical treatment is required; hydration in any form can be fatal
Heatstroke
- Cause: extreme exertion and dehydration impair your body’s ability to maintain an optimal temperature
- Symptoms: core body temperature of 40°C or higher, headache, nausea, vomiting, rapid pulse, disorientation
- Treatment: emergency medical treatment is required for immediate immersion in ice water and intravenous fluids.
SOME TIPS TO FOLLOW (IF POSSIBLE)
Cover your body: Wear lightweight clothing with ventilation. Consider wearing a cap, or better yet, sunglasses to reduce heat buildup in your head. Before setting out, apply a broad-spectrum, sweat-resistant sunscreen with SPF 30 or higher to all exposed skin.
Lower your expectations: accept that the run will probably be harder than expected. Start more slowly than planned and make sure you finish to achieve your main goal. Be guided by time and effort rather than distance and pace.
Cool yourself down: On a long, hot run, take a cup of water to drink at the aid stations and another to pour over your head. If necessary, slow down at the aid stations to make sure you have enough to drink. If possible, carry an extra bottle of water. Do not drink it. Instead, periodically pour some of the water over your head during the run.
Run early: there is no perfect time to run in the middle of summer. However, the early morning hours offer the lowest temperatures and the least intense sunshine (even though humidity will be at its highest).