The Surprising Benefits of Running in Heat

Studies find that heat training can improve VO2 max, resilience, and improved rate of perceived exertion and fatigue, and makes you mentally tougher. Still, running in the heat is hard! The below tips will make it more manageable.

Whitney Heins sweating in the heat in a sports bra and shorts.
Running in high humidity and heat is like altitude training. It’s hard but your body adapts and becomes stronger.

Don’t worry if you are riding this struggle bus this summer. It is HARD but running in heat will pay off when cooler temperatures come this fall. That’s because running in heat is like training at altitude. It is teaching your body to do more with less oxygen. 

This past week, I’ve run in the heart of Texas, back home in sweltering East Tennessee, and now in the low country of Charleston, South Carolina where the dewpoint makes the heat oppressive.

I am focusing mentally on the benefits of heat training rather than my splits because I know that running in the heat is hard for the body but is spurring physiological adaptations that may equal fast race times in a few months. 

So, let’s go!

How does hot weather affect running?

Running in heat makes you run slower.

Your blood volume is decreasing, supplying less oxygen to your working muscles, and giving you less energy.

This makes your heart and lungs work harder. You are sweating which is causing fluid loss which can impact performance by 4-6 percent for every 2 percent of body weight loss. Your heart rate is increasing  2-4 beats per minute in 60 yo 75-degree heat, and up to 10 beats in 75 to 90 degrees. 

What are the benefits of heat training?

As your body learns how to work hard in the heat, it creates adaptations that can make you run faster in cooler temperatures including:

  • lowered rate of perceived exertion
  • decrease in salt in sweat
  • higher blood plasma volume
  • reduced heart rate at a given pace, and
  • earlier sweating

How long does it take to see benefits from heat training?

It can take about one to two weeks to reap the benefits of running in the heat.

How much slower do you run in hot weather?

Therefore, if you are training in temperatures above 55 degrees, you need to adjust your paces.

According to Keith Hanson in the Hanson’s Marathon Method, you can add 5-8 seconds per mile when temperatures reach the 60s or higher.

Here’s the breakdown:

  • If it’s in the 60s, add 5 seconds per mile;
  • in the 70s, add 10 seconds per mile;
  • and in the 80s, add 15 seconds per mile.

Studies have shown that for every 10 degrees above 55 degrees, you can add 1.5-3 percent to your marathon time (e.g. an extra 3 to 6 minutes for a 3:30 marathon with every 10 degrees above 55).

You can adjust your paces using this heat calculator!

Related: How to Get Used to Running in the Heat

Does running in the heat make you a better runner?

running in hot weather tips
Pin these tips for running in heat for later!

Yes, running in heat can make you a better runner. You will run slower in hot weather because your body is working hard to keep itself cool. This work will make you a better runner in cooler weather.

This is because your body is undergoing physiological adaptations to work with less oxygen. Similar to altitude training where your body has less oxygen in the air to breathe in, heat training involves less oxygen to your working muscles to keep you cool. 

Heat training increases red blood plasma volume, offering more blood to carry oxygen to your muscles. Similarly, altitude forces the body to generate a higher number of red blood cells.

Studies find that heat training can improve VO2 max, resilience, and improved rate of perceived exertion and fatigue, and makes you mentally tougher.

All this can make you a better runner come fall. 

What about humidity? Is it bad to run in humidity?

If you are running in heat and humidity, you are a BEAST.

Actually, it is the dewpoint that can make running in heat and humidity oppressive. Dewpoint is when is the temperature when water condenses. If it is close to the air temperature, then running will feel challenging, if not downright oppressive. 

This is mainly because the sweat your body is producing to cool your body has nowhere to go. It cannot evaporate. This then leads to a high core body temperature, stressing your heart and lungs.

A dewpoint that is 70 or above is uncomfortable and approaching oppressive. 

Do you burn more calories running in hot weather?

Yes, you do burn more calories running in hot weather…to a point. Sports dietician Dana Eshelman explains, “Studies show that heat slightly increases your basal metabolic rate in an effort to keep the body cool. However, over time, the body learns to adjust to hotter temperatures.”

Should you fuel differently running in hot weather? 

Yes, you should intake more carbs running in hot weather. The reason is because your body is pumping more blood to your extremities than to your gut. Thus, your body needs fuel that is easy to digest otherwise you will have tummy troubles.
Dana explains, “The initial workouts in heat may feel more difficult than your workouts in cooler temps. There will be a higher heart rate and perceived rate of exertion which signals the body to use more carbs versus fat during your workout. At higher heart rates, the body is pumping blood to the muscles to provide oxygen and nutrients rather than aiding indigestion.”
Simple carbohydrates are quickly converted into energy for the muscles to use. Fat and protein take too much energy to digest. 
Some simple carbs include:
  • dried fruit
  • white bread
  • potato, and
  • sports supplements

Related: Hydration Guide for Summer Running

Is it bad to run in hot weather?

No. Running in hot weather is not bad for you–if you are smart. In fact, running in the heat can be very beneficial to your training.

As noted, research shows that running in heat and humidity is the same as training at altitude. Running in hot weather puts stress on the cardiovascular system making your heart stronger. It also decreases blood flow to muscles because the blood is going to your skin instead, making training similar to that in high elevations.

What temperature is too hot for running in hot weather?

Your body operates best when it is at 98.6°F. Running in heat causes your core body temperature to rise which can lead to dehydration and overheating. Some symptoms of overheating include:

  • muscle cramps
  • excessive sweating
  • headaches
  • nausea
  • tiredness
  • and dizziness.
Running in heat
Running in hot weather can make you slower in the short term but faster in the long term because it is like altitude training.

In dire cases, running in hot weather can lead to heat exhaustion or heat stroke. But these can be avoided if you listen to your body and train smart. I’m here to help!

12 Smart tips for running in heat:


For part of your preparation for your run, race, or workout, pre-cool. Put ice in your sports bra and on your back. Drink more electrolytes, at least 400 mg of sodium before heading out the doot.

Forget about pace. 

Run by effort. Your body is working overtime to keep it cool which involves thicker blood, less oxygen to your working muscles, and an elevated heart rate. This will all slow you down. 

So, instead of running by pace and focusing on your splits, run by effort or rate of perceived exertion. 

Related: What is RPE in Running?

Be an early bird.

Need the motivation to wake up early? Picture yourself trying to do your run or workout in blistering heat, gasping for air, and yearning for water. Think how good it would feel to run in the cool morning hours and get it out of the way.

Alternatively, you can run later in the evening—perhaps after the kids have gone to bed, or your darling husband is getting them ready for bed (because he already ran or had his “me time” for the day).

Related: Smart ways to stay motivated while running

Wear light clothing. 

Duh. Dress for the weather. Here are some of our favorite sun-protective gear: Naute sport sunglasses and Goodr shades for their lightweight feel. The Oiselle flyout tank, Oiselle Mac Roga shorts, and Rabbit Catch Me If You Can shorts for their breathability. Oiselle’s trucker hat for its style and comfort. And Balega running socks for their comfort, breathability and resistance to blisters.

Don’t forget the sunscreen.

My dermatologist Mother Runner friend loves Blue Lizard sunscreen because it’s sweat-resistant, lasts long, and is ultra-protective. Mother Runner Lindsay loves Elta MD sport sunscreen face because it’s the only one she’s found that doesn’t make her melasma worse—a condition she picked up after having her second son.

Related: The Mother Runners Training Plans

Hydrate, hydrate, hydrate.

Remember when Zoolander said, “Water is the essence of moisture?” He was right, go figure! Drink water all day long! And bring this The Nathan insulated water bottle full of icy water with you on your run. Pour it on your head throughout the workout.

Also, drink an electrolyte drink like Nuun or Sword, before, after, and even during your workout to replenish electrolytes and glucose. Remember, too, that sweating makes you lose iron, so be sure to get getting enough! (Get tips here).

Related: Tips for running in cold weather

Benefits of a long run
Run early to beat the heat.

Seek shade.

Head to the path with the most trees to shelter yourself from the sun. If this happens to be a road less traveled by you, check out this gear that holds your phone for safety and run with your RoadID.

Take breaks.

It’s okay to take breaks along your run to drink water, cool off, or just catch your breath. It’s also okay to move a workout to another day when it won’t be so hot, or you know you can head out early or late. You can always adjust your schedule accordingly.

Stop the stink.

Sweaty feet can lead to stinky shoes. Save them (and those within nose-shot) by rinsing them out after a hot run. Then take the insoles out, stuff with paper towels or newspapers, and let them sit in the sun to dry.

Lube up.

Speaking of feet–slather vaseline or Body glide all over your feet to prevent blisters. Also apply to places where any seams touch to prevent chaffing.

Work on your turnover.

One downside of running in hot weather and running slower is that your body doesn’t learn how to run fast. Dedicate one morning a week to running fast repeats such as 200s, 400s, or hills.

Get salty.

What’s the best thing to eat post-hot-run? Salt! Replenish the sodium you lost and get your body temps down with some salty tortilla chips, a popsicle, an electrolyte drink, and a rest. You earned it, mama!

If you want a custom plan to fit your marathon goals with your busy schedule, check out my run coaching services. Also, be sure to check out my free training plans:

8 thoughts on “The Surprising Benefits of Running in Heat”

  1. Great tips. I just want to add that sweaty or wet feet in general can also lead to lots of friction and blisters. When it’s really hot out there, I either use a peppermint rinse or gum to have extra freshness.

  2. Dry max socks are amazing! Can slosh through puddles or a sprinkler and never get a blister.
    That’s so interesting that heat training is the same as altitude. No wonder why I feel like dying🤣


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