Running in the Heat PART 2

Before you get dressed for your hot weather run, weigh yourself (no clothes).  Make a note of it. Then, when you return from your run and strip down, you know that the bulk of weight loss is due to sweat loss and that “water weight” needs to be recovered. You then hydrate frequently till your weight returns to pre-run weight. It’s a simple way to know when you’ve restocked your hydration.

One note: It usually takes a few hours to get your weight back, so have a daily hydration strategy that takes into consideration the depletion from your run.

Heat acclimation

While the body/mind cannot completely acclimate to heat, some adaptations take place that help you deal with it. 

The changes take about 10 days, which is why the first hot days are really tough on you, but over time, the same heat doesn’t seem to affect you as much.

Adaptation number one is sweating earlier in runs. The body is trying to get ahead of the heat gain, so it starts sweating earlier. More blood is shifted to the skin, so it can evaporate the sweat taking heat with it. 

Second, your sweat is more dilute. You essentially ration electrolytes, which are critical for muscle contractions that are lost during periods of heavy sweating.

Because you sweat earlier in runs, your body increases its plasma volume. More plasma volume means you have more fluid available for sweating. 

Lastly, your brain gets used to the feeling of running in hot conditions. Your first runs in hot conditions are tough mentally, but over time, the same run doesn’t cause as many complaints from the brain as before. 

Pre-Heat Prep

If upcoming training or racing are likely to be in hot conditions, you can trigger the heat acclimation by running in extra clothes or indoors in a heated room. Overdressing (wear extra clothes) causes an increase in your core temperature, and the body reacts by starting the acclimation process.

Sitting in a sauna can trigger the same adaptations. The bottom line is that raising your core temperature initiates the adaptations, so you can plan ahead if you’ll be training or racing in hot conditions.

I use this a lot with my runners who train in the winter for a spring race. A few sessions of pre-heat training does wonders in case race day is hotter than they are used to.

During the Run

The Danger Zone

All runners should know the signs of heat illness.  Any hot run puts you at risk, so let’s walk through the signs of heat illness.

Heat exhaustion

Heat exhaustion is the first phase of heat illness. It is characterized by- 

• Heavy sweating

• Cold, pale, and clammy skin

• Fast, weak pulse

• Nausea or vomiting

• Muscle cramps

• Tiredness or weakness

• Dizziness

• Headache

• Fainting (passing out)

For many, dizziness and the sensation of feeling cold are the first signs they feel of heat exhaustion. These symptoms are warning signs, and you must obey them. If you experience these symptoms, slow down your running, take a walk break, seek shade and fluids. Cut your run short and get into a cool environment ASAP. 

Heat stroke

The next phase of heat illness is heat stroke, and this is a life-threatening situation. Heat stroke is characterized by

• High body temperature (103°F or higher)

• Hot, red, dry, or damp skin

• Fast, strong pulse

• Headache

• Dizziness

• Nausea

• Confusion

• Losing consciousness (passing out)

If you stop sweating, you are in trouble. Stop running immediately and seek help.  Get cool as quickly as possible. It seems easy to avoid heat stroke, but since confusion is one of the symptoms, a runner with heat stroke may not make the right decision to stop. That’s why it’s good to have a running buddy, tell others where you are running, and choose a safe route where help is nearby when you are running in the heat. 

Drink Up and Dowse Yourself! (Even on short runs)

Now that you’re knowledgeable about heat illness, let’s talk about ways to mitigate it while running. 

I mentioned it earlier, but on hot runs, no matter how short and easy, you should hydrate.  A few good swallows of a cold beverage every 10-15 minutes does wonders for keeping your core cool and staving off dehydration. 

Place your water bottle(s) in the fridge overnight and add ice to them before your run. Make this a habit for each and every run. Trust me. It will make a big difference during and after the run. 

Also when training in the heat, take every opportunity to dowse yourself with water. Cold water on hot skin takes heat away and makes the brain happier. Dump water on your head. Run through sprinklers. Any extra water on the skin assists the body in removing heat. And if you can, use ice in a bandana or stuff your hydration vest with ice. This works especially well in humid conditions where evaporative cooling is compromised.

NOTE: You may have noticed that some runners are genetically heavy sweaters. If that’s you, then it’s imperative that you focus on daily hydration as well as rehydration after running.