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Running in High Heat and Humidity- Part 1

Now with the intense summer heat and humidity, running almost never feel easy. High heat and humidity have physical effects on our body, we need to run and train differently to be able to keep running without causing any physical issues.

What Happens to Our Body Temperature When We Run in the Heat?

Running makes our body temperature rise and increases our sweat level. Our body also sends more blood to our skin when it gets hot because the plasma in our blood also helps cool our body. While sending the plasma to our skin, our red blood cells come along as well. This process affects other parts of our body:

  • Our muscles need more oxygen-rich blood.

  • Less blood returns to our heart, making our heart work harder.

  • Our body has to decide if it should send more blood to our skin to cool it off or more blood to our muscles to give them fuel.

How Do Heat and Humidity Affect Our Body?

Our body knows how to regulate itself. But when heat and humidity levels rise, our body has to work harder to stay balanced. Humidity is the amount of water in the air. This moisture makes it more difficult for sweat to evaporate off our skin, so we don’t cool off. And here’s why it’s harder to run:

  • Our heart and lungs work harder to make up for less oxygen, leading to exhaustion.

  • When more blood goes to our skin, our muscles get less oxygen-filled blood. This leaves us with less energy to keep up our normal pace.

Prepare For the Humidity

It’s possible to continue to get effective runs during the hot summer months. Running at a slower pace or with lower expectations can be better for our training program than not running at all. We need to use these strategies to prepare physically and mentally for our runs:

  • We need to listen to our body and change our expectations. We can’t focus on how fast we’re running. We need to focus on the amount of effort we burn. If we’re breathing hard and pushing our limits, we’re getting an effective workout, regardless of our pace.

Our Body Will Adapt

The good news is our body will adapt to running in the heat and humidity after about 2-3 weeks. Our body can learn how to cool itself more efficiently and release fewer minerals in our sweat.

Tips to Train in the Heat

1. Run By Effort.

While proper pace is important, it’s time to ignore and run following our body, and how it feels when it’s hot. A heart-rate monitor, or heart rate data from our GPS watch, can be a useful tool to help us follow both easy efforts and workouts such as tempo runs, and it will also alert us if any cardiac intensity.

When running an easy run, we should ignore our pace and concentrate on our breathing and how we feel. Easy runs should feel easy, and in hot, humid conditions, this may mean that our pace decreases substantially. But it’s ok, the benefits will come as our body begins to adjust, and we’ll be surprised by our speed when cooler weather returns.

2. Plan Your Route.

Summer is a great time to get off the roads and run some nice local trails. No matter where we run, we should plan a route that is well-shaded, especially if we’re not running very early morning or night time. The road and concrete retain and generate a great deal of heat, so plan your route to minimize exposure to these surfaces if possible. That’s why trail running doesn’t feel as intense in the heat, and we have access to a bit of wind.

With intense heat and humidity, we have to carry enough hydration, or we can also plan our route near water sources that allow us to drink and refill our water bottle. Natural water sources like streams and ocean, reservoir or lakes also tend to provide a cooler running environment, and jumping in for a quick swim or soak can be incredibly refreshing on a hot day. Jumping in the water even helps to rehydrate our body.

3. Timing is Everything.

When it’s hot outside, timing our run appropriately can often mean the difference between a comfortably challenging workout and a crash. Early morning is the coolest time of the day, especially before the sunrise, later at night after the sunset. For runners who are training for a summer race, to perform one run each week during a hotter time of the day will help and increase the training. But make sure you hydrate appropriately, according to the heat and running distance.

4. Focus on Nutrition and Hydration.

While nutrition and hydration are always essential components of training and racing well, hot summer weather will cause more side effects, if we don’t fuel and refuel enough. We have to pay attention to our thirst and the colour of our urine. A pale lemon colour is ideal, dark urine may indicate inadequate hydration. If you carry some food, focus on foods that can tolerate high heat and humidity. Drinks with electrolytes will help maintain a proper balance of sodium and potassium relative to our water consumption. If we’re planning for a long-distance run, to consume a cold drink helps cool our internal body temperature and delay the inevitable rise as long as possible.

5. Stay Cool on the Run.

In order to stay cool on the run, start by dressing appropriately, wearing light colour tops and technical fabrics that will help wick sweat more effectively. To protect our eyes and face from the sun with a hat or visor or sunglasses is essential. Continuous access to cold fluids is ideal.

When we run long distances, we should plan a route with loops near our home or a convenience store with access to drinks. Splashing cold water on our head throughout the run can also be an effective cooling mechanism since it increases evaporation from our skin.

6. Mental Motivation

While running in the heat has many physical effects, it’s important to concentrate on a nice positive mental motivation as well. To pace ourself appropriately we might be surprised by our performance, especially after 2-3 weeks, to adapt to the heat and humidity. Another great option to stay motivated, happy, and to keep going in a nice pace, is to run in a running group or with some friendly runners.

Training and running in the heat has some benefits, our body does some amazing things to adapt. We will become more efficient at evaporating heat and regulating our core temperature. Over time, our sweat gets less salty to maintain a proper electrolyte balance, and our body learns to sweat at lower temperatures to jump-start the cooling process.

To Train Our Body And Brain In High Heat And Humidity, We Will Reach New PR’s In The Fall, Happy Run !


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