Running in the heat

April showers bring May flowers, higher temperatures, and generally increased humidity. Regardless of where you live, spring brings gradually warmer temperatures that allow you to ditch the leggings and gloves for the tanks and the sunglasses again. In Texas, this can be a wild ride of suddenly hot temperatures and suddenly cooler again temperatures for a few days. Running in the cooler air is not a problem at this point because you are coming off a few months of adjusting to this. It’s your body’s default right now. What is foreign, for now, is the random hot weather you may find yourself running in. In order to continue running your best as the thermometer climbs, there are some things that you need to consider and ways you can set yourself up for success. 

I have done runs in the spring where it was 30 degrees in the morning and when I ran the next afternoon it was over 80. That’s a 50 degree temperature swing. The first and most obvious thing to do in the spring is check the weather every day. Thanks to technology, my phone prompts me to do this every morning. It can literally be any temperature, any weather condition, and can change as you run, so look at the hourly forecast as well the current conditions so that you have an idea of what may happen after you leave home. One idea I employ with days like these is to run with layers and go by my house or car to drop layers or add layers if needed.

Once the calendar turns towards summer, the dress code for running becomes more predictable. My summer runs typically have shoes, socks, shorts, a hat/visor, and maybe a shirt or tank top. It’s not as hard to guess as winter. We know that the goal is to wear as thin and light of clothing as we can get away with… decently. There are a million different “tech” fabrics now and brands that make different workout clothes. If you still choose to run in heavy cotton t-shirts, I frankly do not understand you, but you do you. The benefit of moisture wicking clothes is that they help get the sweat off the skin which helps with the cooling process. They also shade the body from the blazing hot sun and keep your skin safer. As long as you properly apply sunscreen, you can still get some good healthy vitamin D as well. See? Running has lots of benefits! 

Along with knowing what the weather is going to do, you need to be running outside in the weather as much as you can to allow your body to adjust. Your body is awesome. It adapts and changes to the environment around you. When it is hot, the body “learns” to start sweating faster and to shunt blood to the skin to improve your cooling capacity. This is not an immediate change. It is a learned response, but if you do not expose it to increasing temperatures you will miss out on the benefits and adaptations initially. This will make running in the heat even more difficult.

Now, the kicker with how your body adapts to the heat is that it makes your heart work harder to get the blood to the muscles you are using. Remember that blood that gets shunted towards the skin to help cool you and that increased sweat rate? Both of those adaptations make it harder for your heart to supply the needed oxygen to your active muscles. Anyone who has looked at their heart rate data in the summer can confirm this. “So, what does that actually mean for me?” It means you will almost certainly need to slow down a little bit in the hotter weather or you will be working at a harder relative intensity for any given speed on your run. Where your 8:30 pace may have been at 140 beats per minute for heart rate, it may now be 145 or 150 beats per minute (strictly using those numbers for example, real results may vary). 

We covered how you will sweat more and it will affect your heart rate numbers or running intensity, but the other side of that coin is what you will need to do about the water loss. Well. You need to replace it. The bummer with hydration is that you can’t “water load” like we might try with carbs. Once your body is hydrated it regulates the amount of water in the system by excreting the excess, which is a good thing because too much water can actually kill you. Going into a run, make sure you are hydrated. If you ran the night before and are turning around to run the next morning, push fluids before bed and when you wake up. A common tool runners use in the summer is to weigh themselves before and after a hot run (typically for longer runs, but it can be good practice anytime). Sorry to burst your bubble, but those number swings are going to be from water loss in the short term and not a bunch of fat burn. Weighing before and after a hot run can help you gauge how much water you need to replace. A rough rule of thumb is to aim for 20-24 ounces of water per pound lost through sweat. 

The other rule you should keep in mind is to aim for, at minimum, half your body weight in ounces of water each day. As an active individual in the heat, that number will be significantly higher. There are nutritionists out there who can do sweat studies and tell you exactly how to rehydrate optimally with sweat studies. This is something to consider for those who regularly are exercising multiple hours a week in the heat and humidity. In the middle of the summer I more diligently track what fluids I take in. While not required, I typically drink some sort of electrolyte drink immediately after my runs in the summer because I know I am a heavy and salty sweater. This helps get me tracking back in the right direction with my hydration after depleting myself during my run. 

The one pitfall some experience is drinking too many sugary drinks over the summer. We get this idea that “I have to replace my salts!”, so people buy cases of Gatorade or Body Armor and throw them back like it’s a frat party. The problem is that you quietly increase your calorie intake by doing that and that excess sugar is not really necessary after regular training runs. Moderation is key. Please drink responsibly. Along those lines, if you consume alcohol make sure you increase the water intake on the backside of that as well. 

There are several ways to gauge your hydration status and some are more practical than others. Most of us do not have the means to measure the specific gravity of our urine or plasma osmolality, so I do not recommend those even though they give good information. A lot of people use the color of their urine as a gauge of hydration, but that can be misleading at times. What you ate, drank, and even medications can affect the color of your urine and give you false or altered perceptions. Thirst is another means of gauging hydration. If you are thirsty, your body wants water. Mind blowing, I know. We already discussed using your weight to gauge water loss and needs. The best practice is to use at least 2 different measures to keep tabs on your hydration. Thirst and urine color combined will be more telling than either by itself. Those are the two I look at the most during hot summer runs. 

It is hard to run in the summer in College Station. Heat and humidity can make it feel like a dog is panting in your face as you run, but those slogs of runs in July build efficiency in your body and strengthen your cardiovascular system. When that first morning in the 60s hits randomly in September you feel like a superhero running out there because you gutted it out through the difficult months. Be smart. Know your limits and have water easily accessible. It can be very dangerous running in the heat, but if you are smart and diligent you can come out stronger in the fall ready to race!