Adjusting Your Training for Running in Heat and Humidity

Adjusting Your Training for Running in Heat and Humidity

After months of cold weather running, the summer heat and humidity feel like a shock to the system. When you are out running, they literally are. Your cardiovascular system works harder to pump enough blood to the skin to keep you cool. Faster rates of fluid loss can affect muscle function. Overheating can send a signal to your brain to shut down the run. Each year, no matter how many years you have been running, you need to adjust your training for running in heat and humidity as part of the acclimatization process

Training adjustments to heat and humidity will vary widely based on the individual runner. Your current fitness, personal preference and tolerance for hot weather, and geographic location will all impact how much you need to adjust your training at the start of summer. High humidity also requires acclimation; if you live in a humid area, your training may require more adjustment than if you train in an arid region.  There is a reason many elites train in Flagstaff, not the Midwest! 

Some runners may barely need to adjust, especially if summer temperatures gradually increase. Others may need to allow longer to adjust, especially if the weather suddenly changes from 45-degree mornings to 70-degree mornings. 

Temporarily adjusting your training will not harm your fall racing goals. If anything, a focus on long-term, sustainable growth will only benefit you in fall races – and beyond. 

Adjusting Your Training for Running in Heat and Humidity

Always Hydrate!

Summer temperatures raise your core temperature, which results in sweating more than usual. The more you sweat, the more fluids you lose. Fluid loss impairs muscle function, raises your heart rate, and can be dangerous. Hydration becomes of the utmost importance during summer running. Always hydrate before and after runs and carry water even on short runs. Do not forget about electrolytes!

Treat the Heat and Humidity as a Training Stress

It is vital to understand heat and humidity as a type of training stress, just like mileage and intensity. Training does not take place within a vacuum. Heat and humidity make running objectively harder, particularly before you are acclimated for the season.

Too much stress hinders adaptation, increases injury risk, and multiples the likelihood of mental burnout. You do not want to increase multiple training stresses at the same time. Your long-term training will improve if you allow yourself time to adapt to the stress of the heat, before increasing mileage or intensity. 

As you acclimate to summer weather, consider keeping other aspects of your training load the same. The first few weeks of summer may not be the ideal time to increase mileage or start a speed segment. You may even choose to slightly decrease volume or intensity as you acclimate. 

Train for Time, Not Distance

Almost all runners will slow down during the acclimation period, if not during the entire summer. Any run will naturally take longer. If you are limited on time or tempted to push the effort to finish at your normal pace, consider running for time instead of distance. An hour easy run is an hour easy run, whether you run it at a 10:00 min/mile in 70-degree heat or a 9:00/mile in 40-degree temperatures.  

When in Doubt, Run Easy

Many runners possess a tendency to go too hard, too often. When heat and humidity spike, this tendency becomes even more detrimental to adaptation. Running too hard too often when unacclimated to the heat will apply too much training stress. Too much stress hinders adaptation and creates a vicious cycle of subpar runs and performance plateaus. 

An easy run is always beneficial, no matter what your goals are. Want to run faster? Easy runs will improve your running economy. Want to run farther? Easy runs build endurance. If you struggle with heat and humidity, just focus on easy mileage for a few weeks as you adapt. 

If you struggle with controlling your effort in the heat and humidity, consider training with heart rate. Heat and humidity will spike your heart rate, so you will likely run much slower to maintain an aerobic heart rate zone – but in summer, easier is better. 

Modify Your Quality Workouts

If you are well adapted to quality workouts such as tempo runs, intervals, and the like, you can likely continue them during summer. However, you may want to modify the format and scale the intensity as you acclimate. This post details exactly how to modify a speed workout for summer. Opt for shorter intervals and fartlek-style workouts, hill repeats, and leg speed development runs (such as these summer speed workouts). Take your focus completely off of pace, because your paces will be slower to reflect the higher energy demands of running hard in the heat. Your perceived effort is what matters! 

Know When to Bail a Run

There are circumstances that warrant quitting a run, especially in summer. Extreme heat and humidity can be dangerous, especially if you are not acclimated. If you stop sweating, experience lightheadedness or dizziness, or your form noticeably deteriorates, stop running. Those extra miles have no training benefit at that point and the risk of heat stroke or hyponatremia is high.

How do you adjust to summer running?

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7 Responses

  1. It became so hot and humid so quickly that it caught me by surprise. I really paid for that on Saturday’s long run–I was barely able to finish my 10 miler. Time to readjust the goals!

    I’ve utilized HR training to acclimate to the heat. It never fails to amaze me how high my heart rate gets with a very slow pace in the heat. For me, HR is a great objective measure of effort.

    Thanks for this–I am getting ready to embark on my training cycle for Ice Age and I definitely need to adjust!

  2. Thankfully the heat has finally arrived in NH. I love it even though it can make running harder. Definitely knowing to adjust your expectations about times in the heat is important.

  3. Every year the humidity knocks me off of my feet literally. Seems like we go straight from winter to summer. I need to get myself out there earlier this summer. I say that every year! Thanks for linking up

  4. Where I live, I’m pretty acclimated to the heat and humidity. That doesn’t make it any easier, but I am used to it. It’s winter and the cold month or so that we have to get used to.

  5. This is such a timely post for me! I did my first hot and humid run this morning, and it was shock. I dont know why I thought 65 degrees with 91% humidity would work for a virtual race after most of my runs have been in temps under 50. It is so humid here all summer long, thats the worst part for me.

  6. I’m fortunate that I usually don’t have to deal with humidity but the sudden jump in heat even early in the morning has been a challenge. I remind myself that this happens every year (and it’s the reason that I long ago decided not to train for fall races) and that I’ll come out stronger on the other end.

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