Chapter 14 – Extreme Heat
This is the last chapter I’m reviewing in depth: Chapter 12 & 13 focused on multi-day and multi-leg events, and swimming and rowing respectively – not events I’m currently looking at right now. Chapter 15 deals with extreme cold, and Chapter 16 with altitude – I live in the flatlands of the prairies, and even though our winters are exceptionally cold – I’m an indoor runner all winter long for a reason!
Eberle notes that marathoners will usually add five minutes or more to their race as the temperature climbs above 80 degrees. Heat and humidity create special concerns when racing – dehydration is a big issue, and in humid weather your sweat will not evaporate, which can lead to overheating. (Sweat evaporation provides a cooling effect and temperature regulation).
If you will be racing in an unfamiliar environment, it can take a body 7 to 10 days of training to acclimatize to the conditions. Wearing light coloured, loose clothing, resting more, and a finding shady routes can help. Running early in the morning or late in the evening to avoid the high heat of day can also help.
Racers must be aware of the risks of dehydration, hyponatremia, and heat illnesses. Hot conditions can cause dehydration faster than normal, and increased fluid consumption is required. However, at the same time sodium consumption must be monitored closely for the effects of hyponatremia. Rehydrating with water alone increases this risk. Heat illnesses can include cramps, exhaustion, and in the worst case, heat stroke. Weakness, dizziness, chills, nausea and vomiting are all symptoms.
Strategies for Beating the Heat:
Know your sweat rate – calculate your hourly sweat rate, and replace fluids accordingly. To calculate the rate: Using your nude body weight, take:
Pre-exercise weight (convert to ounces) – post-exercise weight (ounces) + fluid intake (ounces) = individual hourly sweat rate
Practice drinking during training.
Consume additional salt. This will help you retain water, ensuring you begin the race well hydrated.
Experiment with salty foods and salt tablets.
Experiment with glycerol, a substance that acts like a sponge, holding extra water in the body.
During the event, have a drinking schedule, and follow it. Start early, and plan to drink every 15 to 20 minutes. Drink to match your fluid losses, based on your calculated sweat rate. Know where water and aid stations will be during the race, and carry extra if you determine you will need more.
After the event, continue rehydrating, and refuel quickly. Drink your recovery calories if food is not appealing.
Many events are held in hot, humid climates. Following some of these suggestions can help you finish a race strong and stay healthy.