Last Updated: February 6th, 2021

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Have you ever experienced the difference between running early in the morning and at noon?  I am sure most of you would prefer a morning run. Ever thought why…well, you feel more relaxed and comfortable in the morning. Why are you so uncomfortable at noon? Any guesses? is the heat…

How does heat impact the running pace?

Heat reduces your average running pace as your heart rate increases by 10 bpm for each degree rise in temperature. Now you have to put in extra effort to run at your average speed when your heart rate is higher than usual. So, it becomes extremely difficult to maintain the speed, and hence you are forced to slow down. However, the reduction in pace varies from runner to runner.

This is in a nutshell of how heat impacts your running…for more…read below…


Is it bad to run in the heat?

No, it’s not at all bad to run in the heat, however, you need to be more careful when you are running in a hot climate.

You may have to take some precautions.

Most often in the tropical region along with heat, a lot of humidity is there.

The presence of humidity is like adding fuel to fire, this makes your run even more challenging.

Running under hot conditions may not be suitable for children, elderly people, diabetics, and pregnant women.

There is an increase in the heart rate in hot weather as compared to cooler conditions.

This impacts your pace and you would be running slow.

Apart from this running in hot weather may lead to other health issues like:

  • Dehydration
  • Excessive sweating
  • Muscle cramp
  • Dizziness
  • Exhaustion
  • Heatstroke
  • Sunburn

When you run, the body temperature goes up and you start sweating in order to lower your body’s temperature.

If you are running where the temperature is hot outside, the core temperature of the body goes up even higher.

You sweat profusely to bring your body’s temperature down to 37 degrees.

You tend to lose a lot of body salt and mineral because of this and will cause you dehydration, muscle cramp, dizziness, and exhaustion.

Dehydration may also cause the blood sugar level to rise.

If you are diabetic and more importantly if you are on insulin, you must check with your doctor before embarking on this adventure.

Apart from the above problems, running in hot may also lead to:

  • Sunburn
  • Skin related problems like dry and itchy skin and in extreme cases skin cancer.
  • Chaffing

Chaffing is very common among runners who run during the afternoon or in high heat.

This is caused by the rubbing of your clothes seams on your damp skin.

They are red in appearance and can be very painful. Also, they may keep you sore for days.

So, if you are someone who sweats a lot, it’s better to use an anti-chaff cream like this one.

These types of creams are sweat-resistant and the above one is non-greasy. So, it will keep your skin protected and you will not feel greasy.

How does heat impact running pace69

Does running in the heat make you faster?

No, running in the heat make you slower.

If you are running in the hot weather, you will possibly be running slower than your average pace.


With every one degree increase in your body temperature, your heart rate goes up by 10 bpm.

When you are running on a hot day, due to the increased heart rate, you will struggle to maintain your average speed.

However hard you strive, after a point, it’s not very comfortable to continue with your usual pace.

This makes you drop your pace.

Even if your pace is decreased, your heart rate is still high.

You continue to work out at a higher heart rate.

If this is continued over a period of time, your body will be conditioned to strenuous workouts in extreme weather conditions.

In a way, you get trained to run at high heat with an increased heart rate.

If you are running in a moderate climate, this conditioning does help you.

You will feel your pace is a bit faster in cooler weather.

This, however, requires a good amount of practice at a higher temperature.

How does running in heat impacts your performance? If you are unsure of your performance during summer, then here are some useful tips to keep your running pace going.

How does running in heat impacts your performance? If you are unsure of your performance during summer, then here are some useful tips to keep your running pace going.

Why is running in heat so hard?

When the climate is hot, and your body is not used to running in heat, the pace decreases.

Your heart rate climbs up or down depending on the intensity of the exercise you are performing.

Let’s say your average running speed is 7 mph and you have a heart rate of 130 bpm.

So when you workout in summer, with every one-degree increase in your core body temperature your heart rate increases by approximately 10 bpm.

With heat as you are running this causes your heart rate to go up by 20 bpm thereby making you slow down.

As a runner, you do not want to compromise on your speed.

You push yourself hard and continue to run at a higher heart rate.

You are exerting too much this way.

This indeed is tedious and it’s difficult to keep going like this for long.

Other challenges that you feel is increased perspiration, thirst, exhaustion, and fatigue.

Running in the sun may cause skin burn and irritation and headache as well.

Another problem that such high perspiration may cause is chaffing.

This is one of the biggest mistakes that marathoners make among the other 26.2.

Chaffing can be extremely painful and you may remain sore for days.

So, it’s advisable that you always use an anti-chaff cream before you head out for running in the heat. 

How do I cope with running in the heat?

Heat makes it difficult for you to run.

The best way is to prepare yourself for running in hot and humid conditions.

I am sharing some tips which may help you to run in the heat:

Adjust to the heat – Our body adapts to heat gradually. So during the initial days of the onset of summer, keep your running minimum. Gradually try and build up your mileage and pace. Your body needs time to adapt to the weather condition and respond accordingly, so be patient with it.

Workout time –  During summers, the sun is harsh and scorching mostly during the daytime. It is better to avoid the midday sun. Try to go for an early morning or late evening run when the heat is relatively less.

Stay hydrated – The sweating that occurs while running on a hot day as compared to a cooler day is much more. So it is necessary for you to keep yourself well hydrated before the run.  Even while running, take small breaks and drink either water or fluid enriched with electrolytes to compensate for the sodium and other mineral loss. Make sure you carry plain or mineral water with you while running. Also, drink plenty of fluids during the day.

Diet – You must not neglect your diet if you plan to run in the heat. You must have a cool breakfast before running. Include some fruits with high water content like melon, watermelon, grapes, peach. You can eat a banana before running as it contains a high amount of magnesium. Include coconut water, avocado, blueberries, spinach post-run. It is better if you carry a workout bar with you and in case if you feel fatigued or dizzy.

Outfit –  Select your workout outfit appropriately. Wear loose fit moisture-wicking apparel. Avoid cotton clothing as much as possible as cotton retains moisture for a long time. Select a lighter color clothing as they reflect heat. Also, wear UV protective sunglasses.

Skincare –  Summer sun is very harsh on the skin. You must invest in a good quality waterproof sunscreen. Apply the sunscreen generously 15 min before going out on all the exposed skin.  If you feel the need you can apply intermittently.

Also, use an anti-chafe cream, if you are planning to work out for more than 30 min in the sun.

Running outdoor vs Treadmill –  As was explained in this article, running outdoor can be more tedious than running on a treadmill. If the temperature is too high it is better for you to run on a treadmill instead. If you are not feeling well or your body is not allowing more, listen to your body and cut down on your run for that day.

Related Questions

Is it better to run in the cold or in the heat?

We have seen the effect of heat on our run.

Running is comparatively easier when you are running in a cold climate.

The stress is lesser on the body in cold conditions.

You sweat less and hence chances of dehydration are less.

The only problem in winter is the less temperature and the chill wind.

Running under freezing cold temperatures may not be a very good choice as it may lead to lung burn. 

If you want to start running, cold weather is better as there is less stress on your body.

In a hot climate, you push your limits and in this way, you condition your body.

So there is no generic answer to which is the better climate to run.

It depends on your perspective and preferences and needs.

Should I wear a hat when in the heat?

This again is your choice.

Wearing a hat or a lightweight cap protects you from the harsh sun.

The downside is that it prevents body heat from escaping.

With the hat on, you will trap the heat.

Try to get a light cap with sufficient air-vents that has a sweatband and preferably light color.

This may reduce sun exposure and keeps the heat-dissipating. 

Summer running has a definite impact on your running. It will impact everything from how you run and what you wear and your performance. Here is an exact guide of what summer running can do to you and how to survive it.

Summer running has a definite impact on your running. It will impact everything from how you run and what you wear and your performance. Here is an exact guide of what summer running can do to you and how to survive it.

Madhusree Basu

Madhusree Basu

Author, Admin

Blogger and a fitness enthusiast. She loves running and Yoga and everything in between. She started running to manage her weight and to eat to her heart’s content. A true foodie at heart she shares whatever knowledge she has gained throughout the years about weight management and fitness.


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Sessions, J., Bourbeau, K., Rosinski, M., Szczygiel, T., Nelson, R., Sharma, N. and Zuhl, M., 2016. Carbohydrate gel ingestion during running in the heat on markers of gastrointestinal distress. European journal of sport science, 16(8), pp.1064-1072.

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